Wireless Magazine 1933 08
Wireless Magazine 1933 08
Wireless Magazine 1933 08
::
-4911111111.11
[Wireless Magazine.
August. 1933
GARARD
QUALITY PRODUCTS
Garrard Record -
Universal
Electric Radio Gram.
Unit, manufactured
completely universal
on all usual current
supplies
6 Bs. 6d.
GARRARD ENGINEERING
WILTS.
Garrard No. 30
or
17
n
Editor
Wireless Magazine
BERNARD E. JONES
Technical Editor
D. SISSON RELPH
J. H. REYNER,
Vol. XVII
(Hons.), A.M.I.E.E.
B.Sc.
Assistant Editor:
AUGUST,
Research Consultant:
No.
1933 :
W. JAMES
103
From Sound to
we learnt about heat, light and sound;
it now seems that in radio the order will be
reversed.
We learnt first how to handle sound,
and now we are learning how to transmit and work with
light by radio; in a few years we may be dealing with
AT school
W. Harris,
M.Inst.Rad.E..
By Percy
25
IRON-CORE THREE.
By Paul D. Tyers
THE SELF-CONTAINED FOUR-WITH IRON CORE COIL AND CLASS -B OUTPUT.
By trL
..
..
..
30
54
56
68
SCOPHONY
ITS
BASIC
Special Correspondent
..
PRINCIPLES.
TONE CONTROL
NEW A.C.-D.C. MAINS VALVES
HOW TO DESIGN A D.C. SET. By
HOW TO GET REAL QUALITY.
ADVANTAGES OF
Bonavia-Hunt, M.A.
WATCHING
Tyers
..
..
..
..
G. S. Scott
By Noel
..
..
By Paul D.
..
..
16
23
32
37
42
46
53
CATHODE-RAY
..
..
OVER
..
..
..
..
..
..
63
69
73
74
..
..
.
By
74
75
75
76
76
79
81
. .
82
86
..
..
..
60
62
GENERAL ARTICLES
GUIDE TO THE WORLD'S BROADCASTERS.
Jay Coote
By
..
H.
Short Story by J.
COUNTER.
man
THE
Godchaux Abrahams
SET AT WORK.
..
..
..
By
TECHNICAL FEATURES
VALVES TO USE IN YOUR SET
Contents
CONTROL OF VOLUME
WE TEST BEFORE You
Radio
THE "
"Light"
El
6
8
12
15
By Whitaker -
Wilson
..
SUMMER RECEPTION.
Harris, M.Inst.Rad.E.
..
By Percy W.
Henn ..
..
By Kenneth
ELECTRONIC MUSIC
.
ON THE CREST OF THE WAVES. By Jay Coote
CHARGING WITHOUT MAINS ..
..
..
Noms AND NEWS
..
BLUEPRINT AND INFORMATION COUPONS
..
INDEX TO ADVERTISERS
..
..
..
51
52
53
62
65
70
77
78
81
86
88
94
94
96
96
GRAMOPHONE FEATURES
GRAMOPHONE -MOTOR HINTS.
By P. Wilson,
29
CHOOSING YOUR
By Whitaker -
33
18
41
59
By T. F.
..
..
..
SETS THAT CHANGE THEIR HABITS. By Percy
W. Harris, M.Inst.Rad.E...
..
..
RADIO MEDLEY. By BM/PRESS
..
THE WIRELESS Loo : THE STICKER. Verse ..
Jowers
40
M.A.. .
RECORDS.
..
..
45
72
92
VISIT US AT OLYMPIA
STAND 10
Registered at the General Post Office for transmission by Canadian Magazine Post
AUGUST 15 to 24
Postage on this issue,
Wireless Magazine.
August. 1933
ESTOUSEINYOUR
.te
14
u 1I 11
__
Make
.-
Type
`xa
..
..
Osram
Six -Sixty
Listen
21ORC
..
..
H210
210RC
H2
H2
PMIA
H2
H2
Six-Sixty
..
Osram
Mallard
..
..
..
..
..
2101-1F
..
..
Mazda
..
..
Mallard
Marconi
Osram
Cossor
Lissen
Mazda
Marconi
..
..
Mallard
..
Six -Sixty
Mazda
..
..
..
Marconi
Osram
HL210
40
35
50
50
45,000
50
.1
41,600
35.000
35,000
50
35
.2
33
25.000
19
3.0
32
.5
1.5
24
23
.2
.4
2.0
13
26
.4
.4
2.0
27
.5
27
.5
.5
1.0
1.0
8,000
8,000
6,000
5,800
3,000
2IOLF
2,500
PMILF
L210
2,000
2,000
Marconi
..
L2I0
..
..
2,000
Mallard
Six-Sixty
Cossor
Lissen
Mazda
Marconi
Osram
PM2DX
210D
210LF
L2
L2
P2I5
P215
220P
P215
PM2
P220
220P
Lissen
Cossor
..
Cossor
..
215P
Cossor
..
220PA
Mazda
Mallard
Lissen
Marconi
Six -Sixty
Mallard
Mollard
Six -Sixty
Mazda
Listen
Lissen
Listen
Mazda
Mazda
Six -Sixty
Mazda
.92
2.0
2,000
0.00(1
1.5
1.6
0,000
4
0,000 20
0,000 19
5,000
7
5,000
7
4,800
7.2
4,400
7.5
4,400
7.5
4,0001 7
4,000
9
.4
2.0
2.0
3A
3.0
3.0
6.0
6.0
.5
5:0
1.4
2.0
.9
.4
.7
.75
5,0
5.0
.7
Listen
..
Micromesh
Mollard
Mallard
Osramxt
Mazda
Mallard
..
Cossor
..
..
Osram
Listen
Six -Sixty
Mallard
..
..
..
..
..
..
Lissen
Marconi
Osram
Cossor
..
..
..
..
..
Mallard
Six -Sixty
Cossor
Lissen
..
Marconi
..
..
..
5.0
3,900
3.85
6.0
3,900
3.85
6.0
..
P220
3,700
2.5
3.4
5.0
Marconi
..
..
..
..
220PA
PM2A
3,700
3.5
3.5
3,500
2,150
2.5
2.0
6.0
6.5
9.0
Osram
Six -Sixty
Cossor
Mallard
Lisses
Marconi
Mallard
Six -Sixty
Marconi
Osram
Cossor
Listen
Cossor
Osram
Cossor
..
..
LP2
P2
3,600'
..
..
..
..
..
..
3.5
3.5
2.0
3.4
3.5
3.5
P2
2,150
220SP
PM202
PM252
240SP
P220A
P220A
2,060
2,000
1,900
1,900
1,850
1,700
PX240
1,500
4.5
230XP
1,500
4.5
6.6
6.5
3.7
3.5
3.5
3.5
3.0
3.0
..
..
DG2
DG2
210DG
PMIDG
2IODG
3,750
3,750
--
3,400
4.5
4.5
2.7
--
1.2
1.2
.8
.8
.8
..
..
..
..
..
..
Osram
Marconi
Marconi
Osram
Six -Sixty
..
..
..
..
..
..
S215A
SG215
218SG
S215B
800
1.1
500
500
700
I.1
500
1.5
PM12A
215SG
S215
727,000
455,000
357,000
334.000
333,000
330,000
300,000
300,000
500
330
1.5
I80
0.6
22CSG
200,000
320
.6
522
S22
200,000
200,000
200,000
200,000
190,000
180.000
350
350
.75
.75
5B1
S21
S21
215SG
PM12
1.4
2.1
1.1
220
220
200
.1
.1
.05
200
.1
..
SG2V
S215VM
220VSG
VS2
350,000
350,000
110,000
600
1.7
700
2.0
--
1.6
1.25
0.0
4.0
4.0
4.0
1.0
2.0
2.0
8.0
---
.8
1.6
1.0
.5
1.25
1.5
3.0
2.5
3.0
3.0
2.0
---
7. 0
Mallard
Six -Sixty
Mallard
1.25
10.0
Six -Sixty
2.3
2.5
2.5
12.5
13.5
Mallard
Listen
Listen
Cossor
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
4 -volt
..
..
..
Mallard
Six -Sixty
Marconi
Osram
Marconi
Osram
Marconi
Osram
Listen
Six -Sixty
Osram
Cossor
Mazda
Mallard
Six-Sixty
Six -Sixty
..
..
..
..
..
..
.
..
..
..
2.5
2.5
5.0
60,000
60,000
58,000
55,000
50,000
21,000
20,800
20,800
20,000
40
.66
40
37
38
.66
.66
.64
.66
40
.8
25
25
25
.2
.2
22
.1
14
.05
13.5
17
.I
40
.35
I.'
.55
.3
.6
2.5
1.25
1.25
1.0
.2
Cossor
Mallard
Marconi
..
..
..
..
..
Six -Sixty
Cossor
..
..
8
8
2.25
..
P6I0
610P
P610
625P
2,500
P625
P625
P625
3.5
Marconi
Osmm
3.0
Six -Sixty
L410
8,500
Lisse
7,500
.77
2.0
3.0
PM4DX
15
15
Cossor
410D
7,250
14.5
2.0
2.0
4.0
P410
5,000
7.5
1.5
P410
410P
410P
PM4
P410
P425
PM254
5,000
4,100
4,000
7.5
1.5
1.9
4,000
7.8
8
8
8
2.0
420SP
P4I5
P4I5
425XP
P425
1,500
4.5
3.0
415XP
PX25
4XP
1,500
1,265
1.260
4.5
9.5
4.8
3.0
10.0
14.0
14.0
13.0
14.0
15.0
7.5
4.0
18.0
2.0
3.0
2.4
2.4
3.5
120
.9
PMI4
80J,000
230,000
800
200
1.0
.87
4075SG
220,000
190
5410
5410
200,000
200,000
180
200
50,000
42,000
42,000
28,000
41513-1727000
100
120
120
1.0
2.85
--
3.0
3.5
13.5
8.0
8.0
---
70 2.5
60 12.2
100 l 4.0
15.0
2.5
12.0
14.0
16.0
-- --- -- -
25,000
.871
.9
2.0
2.0
2.85
2.4
1.75
3.0
2.0
60,000
60,000
60,000
40
40
40
58000
42
40
50,000
49,000
30,000
40
30
.66
.66
.66
.7
.8
.85
1.0
..
..
..
7.8
8
2.5
8.0
6.0
2.8
13.0
2,500
2,400
7.5
6
3.0
2.5
2,400
2.5
610XP
PM256
625SP
2,000
25
1,850
1,780
5.8
3.25
3.25
P625A
1,600
3.7
P625A
P625A
1,600
2.3
3.7
2.3
1,500
4.5
3.0
12.0
625SPA
l'N1256A
1,500
1,400
1,300
3.9
3.6
3.5
2.6
2.6
20.0
20.0
20.0
P650
15.0
1.0
.35
35
5
.75
.5
1.0
2.7
..
..
..
610SG
PMI6
S6(0
S610
210,000
200,000
200,000
200,00(1
200,000
190
.9
200
200
1.0
1.0
1.05
210
210 11.05
8.0
11.0
11.0
15.0
8.0
8.0
20.0
16.0
--
4.0
4.0
..
..
,.
Mollard
PT625
PT625
SS617PP
PT6S
Make
143,000
80
1,85
0.0
43,000
28,500
80
54
1.85
0.0
1.9
5.0
24,000
GO
2.5
4.0
7.0
5.0
6(5P1'
PM26
- -
Type
88
ao
5`
I4 0
1.95
9.0
..
3.4
3.0
3.0
7.0
8.0
6.0
6.0
2.28
2.28
2.28
2.3
1.5
8.0
75
7.0
2.0
3.0
6.5
5.0
..
6.0
6.0
4,600
2.300
2,150
2,150
2,080
2,080
2,000
4.5
6.5
..
..
Mallard
Osram
Marconi
.77
2.0
Mallard
Mazda
.8
HL610
2.0
Six -Sixty
.7
H610
H610
H610
6075RC
6IORC
PM5B
7,500
3,550
3,500
3,500
3,500
3,400
3,200
..
Osram
Lissen
15
Listen
Marconi
Osram
Six -Sixty
7,500
..
..
Marconi
15
PM24
4Pen.M
4Pen.SP
L610
L610
PM6
610P
P610
..
Lissen
Marconi
Osram
Cossor
Mollard
Six -Sixty
8,500
8,500
41OPT
2.0
2.0
2.0
2.0
2.0
2.0
2.0
..
..
12.0
L410
L410
Pen.425
L610
610LF
8
6
..
1.3
410LF
PT25
8.5
9,000
8.000
7,500
Cossor
2.5
2.0
3.0
2.5
PT425
PT4
PT4
PT425
9,250
..
1.6
610D
PM6D
Osram
Mallard
Cossor
Marconi
Osram
Six-Sixty
Listen
13,000
12.500
10,000
SG410
410SG
2.0
8.5
240B
40751-1F
IA
.I
1.8
2.5
PM2B
HLD410
HL410
HL410
410HF
PM3
.3
Cossor
5.0
4.5
4.0
I.0
2.5
1.75
.2
Marconi
5.0
20
26
7.5
6.5
10.0
6101-1F
Cm
.0
,2
.0
30
25
10.0
60,000
15,200
14,700
2.0
14.0
30,000
21,000
20,000
O
9
S y.
20,000
64
2.5
2.5
2.5
2.5
HL610
HLD610
'
PM5D
607HF
PM5X
28,000
FD22O
H410
H410
4075RC
PM3A
410RC
..
..
,.
..
64,000
Pen.220A
Pen.220
Pen BI
PM22A
PM22
H410
..
1.4
Osram
Listen
Cossor
100
80
PT2
Osram
Mallard
Six -Sixty
7.5
7.5
---
I.4
230PT
23011PT
.___
<m
.7
220Pen.
4.0
35
.r
1.25
PT2A
PT2
Marconi
Mazda
Mazda
Cossor
Listen
Mazda
Cossor
Osram
.92
Cossor
4,000
Osram..
Mallard
2.6
2.0
Tre
Make
-- --- --..
-- --- -..
..
- ..
-Sixty:
- -2 -volt Class -B Valves
..
-- -- --- --.
PBI
LP2
LP2
Micromesh ..
Mulla d
..
Cossor
2 5
.9
PT240
220PT
220HPT
5.0
5.5
..
Marconi
Osram
Cossor
Mallard
Six -Sixty
.85
230PP
6.0
..
Cossor
2.5
..
2.25
4.0
..
Osram
2.2
71,000
Cossor
Cossor
Six
PMI2V
2I5VSG
SS218VS6
PT225
2.25
..
Six -Sixty
,5
.15
5
0.6
2.0
-w
>
VS2
9
6
..
Osram
24
24
1.2
1.0
=Q
- ..
2 -volt Pentode Valves
4,000
4,000
Micromesh ..
Marconi
Cossor
.6
..
..
..
I.0
.87
.8
,.
.,
..
Six-Sixty
.75
.1
8,590
Lissen
.0
24
35
2IOHL
HL2 I0
HL2
HL2
HLBI
Marconi
Mullard
Six -Sixty
Six-Sixty
Listen
22,000
21.000
20,000
20,000
20,000
..
..
..
.6
22,000
PMIHL
Type
l3
.75
1.0
1.0
.0
HL2
HL2
HL2I0
Mollard
Osram
Six -Sixty
2.0
210HL
2lODet
Mazda
Mollard
.7
.1
1.5
1.0
1.5
21014F
..
..
..
.1
20
Six -Sixty
..
.5
1.0
23,000
22,500
Cossor
..
..
.8
0.7
PMIHF
Micromesh ..
Cossor
..
..
50,000
50,000
45,400
45,000
18
Make
r C'
Cossor
Ei
2.0
2.0
Mc
2:1
c2
S
a
,eN
05
Mallard
Cossor
..
Cossor
Cossor
Six -Sixty
..
Mallard
Listen
Mazda
Cossor
..
..
..
..
..
..
Marconi
..
Osrarp
..
Micrrmesh ..
Six -Sixty
..
Mazda
Marconi ..
Osram
,
Cossor
Six -Sixty
Mallard
Six -Sixty
Mallard
Osram
Marconi
Mollard
Listen
Mazda
Cossor
Mallard
Cossor
Mazda
Mazda
Six-Sixty
Marconi
Osrain
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
4DX.AC
36,000
7.5
2.1
904V
34,000
9,500
8,000
4,800
2,000
2,000
75
3.0
AC/HL
AC(HL
41MHL
AC2HL
MH4
MH4
1,700
1,700
1,500
36
36
35
35
52
2.2
2.6
4.0
2.8
3.0
3.0
3.0
3.0
4.5
1,500
75
6.5
1,100
1.100
40
3.5
HLAI
4H LAC
80
25
20
20
4.75
4.75
4L.AC
10000
9,500
8,000
8,000
7,900
5,000
3.6
3.6
8.0
2.65
2.5
2.5
164V
4.850
SS4PAC
3.3
3,170
8.5
3,000
11.0
ML4
ML4
ACI04
AC/P
AC/P
41MP
2
2
3.8
104V
2,860
2,860
2,850
2,860
2,650
2,500
2,000
4.0
17.0
4.2
4.2
25.0
25.0
4IMRC
4IMH
4IMHF
4GP.AC
354V
MHL4
MI -1L4
4IMLF
AC064
4IMXP
PP5/400
AC/PI
1.500
1,500
1,450
1,450
HV4/1
1,265
PX25
PX25
1,265
Continued on page 4
50
72
41
40
1.9
16.0
2.0
2
0
0
0
18.7
6
2.0
3.0
4.0
4.0
6.0
3.0
4.0
6.0
10.0
10,0
9.0
8.0
3.5
11.0
3.6
20.0
3.75
7.5
9.0
5.4
6.3
3.0
7.5
6.0
3.7
3.0
9.5
9.5
7.5
7.5
11.2
1.8
2.7
13.0
24.0
200
30.0
26.0
20.0
18.0
--
Wireless Magazine.
August, 1933
ACCURACY
immediate
3,,
de-
livery.
By plac-
ing their
orders direct
proachable
35/
Telephone :
Temple Bar 8620.
Adel. of
The City Office and Works : 7 Angel Court,
Aecumu.
173, Strand, London, W.C.2.
tato. Cv.
Ltd.
Telegrams :
Microscopic examination
ensures absolute perfection for all Radiophone
products.
RADIOPHONE
Products
THE LONDON
ELECTRIC
"
Wireless Magazine
3
"
advertisements
Wireless Magazine.
-VALVES
TO
E
Make
Type
August. 1933
USE
m1=
.T.
rio
830
830
6.0
6.0
5
5
35.0
35.0
NI1-14
.
MH4
A.C.
Osram
40
40
--
3.6
3.6
-..
A.C. Pentode
VMS4
VMS4
Marconi
Osram
2.6
12.6
Valves
MFT4
<.0,000
MFT4 100.0001
Marconi
Osram
--
3.0
120
12013.0
Cossor
7.01 .1
.25
70,0001
40,000
IG
Six -Sixty
Mallard
Mazda
Cossor
Marconi
Micromesh
Osram
S;x-Sixty
Mallard
Cossor
Mazda
..
..
..
..
..
..
..
..
..
cr
3.2
3.2
4.0
900 3.0
750 2.5
750 3.75
3.5
3.5
1.0
1.5
1.1
5.0
2.0
..
..
..
..
..
Mallard
Cossor
Six -Sixty
MS4B
MS4B
AC/SG
4YSGAC
S4VB
350,000
350,000
340,000
300,000
257,000
200,000
MSGLA
4.5
3.5
8.0
9.5
5.2
1.1
Micromesh
Mallard
Mallard
Osram
Six -Sixty
Six -Sixty
Osram
2.5
3.0
3.0
4.0
..
..
..
..
VSGAI
MM4V
VM4V
VMS4
4MM.4C
4VMAC
VMS4B
..
Mazda
..
Micromesh
PT4
PT4
MPT4
MPT4
MS.Pen.A
MP.Pn.
..
Micromesh .
Mallard
..
Mallard
Mallard
.
Mullard
..
3.0
6.5
3.0
1.2
5.5
10.0
8.2
2.4
3.0
1.1
3.0
8.0
42,000
42,000
120
120
2.85
2.85
32.0
32.0
33,000
33,000
100
100
3.0
3.0
32.0
32.0
4.0
4.0
9.0
30.0
30.0
40.0
------
AC/Pen.
7A2
PT41
PT4IB
PenAl
PM24A
PM24B
PM24C
PM24M
2.5
3.1
3.0
3.0
--
2.6
30.0
3.0
30.0
2.25 30.0
30.0
3.0
2.0 20.0
meee
d'
Filament Current
Mazda
Mazda
2.1
3.0
3.0
30.0
30.0
30.0
DC3HL
DC2P
.1
Ampere
11,700
35
3.0
10
3.75
2.5
15.0
2,6501
..
..
..
Marconi
Ostern
Marconi
Osn.m
DH
DH
DL
DL
40
12
3.7
3.7
4.5
25.0
2,660
12
4.5
25.0
2.7
14.5
15.0
40
..
6.0
10,800
10,800
2,660
Mazda
Mazda
2,2201
DS.1P
10
6.0
3.0
14.0
-------
.. SS4Pen.AC
..
Pen.4V
.. AC/PT
Mullard
-7 8
Pentode Valves
A C.
Marconi
Osram
Marconi
Osram
Cossor
Cossor
Linsen
Cossor
Cossor
4.5
..
2.el
2.4
-----
.. AC'SI.VM
Six -Sixty
2.0
..
Mazda
Mazda
2.1
3.3
AC!SGV 300,000
MVSG
200,000
VMS4
-__.. ACfSG.VM
Cossor
Marconi
24'
13
-- --_
----_
--
..
..
Linsen
'g,
1,120
1,120
1,100
-:-900
4YSGAC
Type
Cm
2.5
4.0
2.5
5.8
2.5
1.1
!flake
page 2
from
`El
a
ca
PX4
PX4
Type
Ostar....
Make
cox
N YOUR SET-Continued
Filament Current
- Ampere
.1
.. DC2SG
11,200 12.2
Filament Current :2 Ampere
.. ID:2ISGVMI
1,200 2.2
Filament Current .25 Ampere
Mazda
Mazda
..
Osram
Marconi
Osram
,.
Marcos;
500
500
1,120
L1
1.1
2.5
540,000
350,000
3.2
3.5
350,000
1,120
3.2
3.5
..
2.4
..
'IDS
Filament Current .5 Ampere
..
DC/SG
1,00012.75
Marconi
Osram
4.0
550000
DS
DS
DSB
D56
..
4.5
2.5
VDSCossor
Mazda
4.0
Mazda
DPT
Marconi
Osram
13.0
30,000
90
3.0
140.0
..
DPT
30,0001 90 13.0 140.0
Filament Current .5 Ampere
3.0
I3.5
.. DC/Pen.
1
Mazda
- -
Dario..
Tungsram
Tungsram
Triotron
Triotron
Triotron
Tungsram
Tungsram
Dario
Dario..
Triotron
Triotron
Triotron
Tungsram
Dario..
..
..
.
..
..
..
..
..
Dario..
35
25
25
25
32
32
L210
16,000
16
LD2I0
HD2
14,000
12.500
11,000
7,500
10,000
10,000
SD2
..
..
TD2
LG2I0
0.7
.6
18
15
2.0
1.8
209
.8
2.5
.2
.0
3.0
2.5
2.5
9
10
17
..
Sup. Det.
8,000
7,500
10
15
YD2
ZD2
E235
P215
Sup.power
UD2
LP220
SP230
Hyp. Pwr.
E235
SP2
3,600
4,200
3,500
3,500
3,000
2,800
2,600
2,500
2.400
2,600
2,000
2.5
1.2
3.5
..
'Cungsram
Friotron
1.5
1.5
.6
.0
1.25
.2
..
..
1.0
1.0
1.0
1.5
.0
.0
.0
PD220
Un. Bi v.
Tungsram
Tungsram
WD2
Detector
H210
HR210
Sup. H.F.
50,000
25.000
25,000
25.000
20,000
20,000
R208
12.5
5
6
5
7.8
5
7
9
3
..
5,0001
5,0001
DG210
DG2I0/0
..
0210
5
10
.7
1.25
2.5
3.0
2.0
8.0
7.0
9.0
8.0
9.0
8.0
6.0
1.5
2.0
1.8
3.0
2.0
3.0
3.5
15.0
12.0
12.0
12.0
1.5
1.0
1.0
11.5
Tungsram
Triotron
Dario..
333,000
200.000
400
200
1.0
3.0
200,000
200
1.0
2.0
1.5
Tungsram
"lrotron
SV20
S208
2 -volt
Tungsram
Dario
Triotron
Tungsram
..
..
11.51
6 -volt
..
Tungsram
10
12.0
Pentode Valve
PP6I0
40,0001
60
1.5
..
..
Tungsram
Triotron
Dario..
AR4101
13,300
40
A430N
7,000
7,500
6,250
4,800
3,000
3,000
2,500
1,000
1,000
1,000
24
24
24
.. SuperDet.
..
AG495
YN4
..
.. Sup. Pow.
Tungsram
Triotron
Dario
Triotron
Tungsram
Triotron
Triotron
Triotron
..
..
..
.
Tungsram
Triotron
..
..1
Tungsram
Dario
Tungsram
Triotron
Triotron
Dario..
3_0
0.8
3.0
E430N
AP495
--
K435/l0
3.0
3.5
3.2
4.0
2.5
3.0
3.0
4.0
3.5
12
9
9
10
3.5
3.0
5.0
..
..
..
5,000
DG4100
D410N
Triotron
Tungsram
..
.5
3.0
3.5
2.0
6.0
6.0
5.0
8.0
14.0
10.0
15.0
35.0
65.0
100.0
LOI 3A
I.0
..
AS494
SG
AS495
5412N
667,000
600,000
428,000
584.000
1,000
700
1,500
700
..
S410N
400,000
400
Super SG 300,000
S430N
300,000
AS4100
180,000
250
..
..
..
..
Tungsram
PP200
150,000
300
2.5
Poly
P215
40,000
37,500
33,000
60
60
1.5
6.0
125
11.5
8.0
50
1.5
10.0
Dario
Tungsram
Triotron
Triotron
..
..
..
AS4I04
VMSG
1.1
1.5
1.5
1.0
1.2
1.0
1.5
4.0
900
3.0
3.0
900
3.0
1.5
3.0
AS4105
S431N
S415N
300
250
- -
P440
25,000
24.0
24.0
32.0
20.0
30.0
3.5
3.5
3.0
3.0
175
175
100
60
3.5
4.0
75
100
45.0
Triotron
Tungsram
Dario
..
..
Tungsram
Triotron
Tungsram
..
..
..
Dario..
14,500
13,300
11,000
38
G2018
E2020N
7,000
25
6
P2018
Sup. Pwr.
2,800
2,400
A2030N
R2018
Sup. Det.
2.6
3.0
3.5
40
33
3,000
4.0
2.0
6.0
3.5
4.0
2.0
2.5
2.5
10.0
1.1
4.0
20.0
15,0
Dario
Tungsram
..
..
..
Triotron
Triotron
360,000
333,000
400,000
300,000
SG
S2108
52010N
52030N
400
400
400
900
1.2
1.0
1.5
4.0
3.0
3.0
..I
5E2018 1360,000
52012N
500
I
1.4
11.0
3.0
I
550
400,000
300,000
208,000
P430
50.000
50,000
33.000
20,000
22.000
P440N
Poly.
AFP4I20
APP4I00
1.5
3.5
Pentode Valves
PP230
SP614
..
..
..
..
3.0
8.0
8.0
Triotron
Dario..
Tungsram
Tungsram
Triotron
Triotron
1.0
I
12.0
..
..
2.0
3.0
2.6
6.6
3,300
3,300
2,300
P610
P615
A C. Pentode Valves
1.5
1.5
Tungsram
Tungsram
Tungsram
Tungsram
Tungsram
1.3
1.0
1.2
3.0
1.5
4.0
6.0
3.5
--
..
..
..
P2020N
PP2018
D.C.Poly
40,0001
31,250
80
80
30,000
75
It
2.5
2.5
20.0
20.0
..
..
..
..
..
..
5E2018
S2018
R2018
G2018
P2018
PP2018
360,000 500
333,000 400
13,000
40
6,500
25
2,800
7
80
31,250
1.4
1.2
3,0
3.0
3.5
2.5
2.5
2.0
4.0
20.0
25.0
1,5
Wireless Magazine,
'Co
TUNI
August, 19331
at
last
E
UNIVERSAL
NC
COILS
VALVES
ONE VALVE
FOR BOTH
owner."-SUNDAY
May
B.P. 30.
or Tuned
Aerial
Grid with reaction
B. P.31. H.
Tr nsfornIntercahe
er win,
F.
Reactlw
10,6
17.
0/
"
quired."-WIRELESS WORLD,
33-
June 9.
Type
R 2018
G 2018
P
2018
PP 2018
S
2018
5E 2018
HP 2018
HPE 2018
V 2018
Use
mains consumption.
Full range available-Variable Mu, Screen grid, High slope Detector, L.F., Multi
40
25
G.P.-L.F.
Power
Screen grid
Vari-mu Screen grid
(Slope-I.2mA V)
H.F. Pentode
H.F. Pen. Vari -mu
Half-Wave Rectifier
F.
lmped.
400
5,000
2,000
2,000,000
1,000,000
80
Output
Price
0/6
13,000
7,000
2,500
30,000
333,000
10
Multigrid output
these
Ampl.
Detector
with
Universal
D. C. A.C. Valves.
All
valves, including rectifier, in-
.350
.750
0)6
1.400
7/4/6
4/6
---
70 mA
3/ -
4/6
416
0/6
21
built
blessing
t-
illustrated literature.
UNIVERSAL
TUNGSRAM
'PHONE: MUS.
FOREMOST AS PIONEERS
of Oliver
Control Ltd.,
Advt.
Pell
103
Kingsway. London,
W.C.2
"
saw
5
5053
VALVES
Wireless Magazine.
August, 1933
Metres: 30
Kilocycle
Metres : 31
9,672
Power :200 w. HEREDIA (T14NRH)
Kilocycles:
Co_
10,000
Spain
Mean Time.
Announcer
.Announcer : Man.
Call : "Aunt Madrid Radio difusion Ibero-Americana." Announcements are made in Spanish and English.
Time of Transmissions : B.S.-l'. 00.00-0.2.00 daily; special concert
for European listeners, 19.00-02.00 (Saturdays). Twice weekly the
station relays a programme from the Madrid (EAJ7) studio.
Power
: 1
kw.
POZNAN
(SRI)
Poland
Kilocycles
9,490
Man.
22.311
and 23.30.
`4983s
Power :
Announcer : `,1'otnan.
Call : "Hallo, hallo, Radio Poznanskie."
Interval Signal : Short carillon and metronome.
Call:
Metres
Power:
239
2 kw.
NRNBERG
Metres: 518.1
Kilocycles:
Power
1,256
Germany
Call
1,145
15
Kilocycles:
Switzerland
VIENNA
rlsl ri tl
Kilocych
579
100 kw.
Power.
.4
Metres:
6,02-
Illinois, U.S.A.
I kw.
728 miles.
TI4N-
Call.
Times of Transmission
Closes down with good -night greetings in Spanish and English followed
by the Spanish Republican National Anthem, Himno de Riego.
Metres: 31.6
ta Rica
by JAY COOTE
Metres: 1,200
262
Power : 6 kw.
ISTANBUL
Turkey
Kilocycl
250
Announcer
Man.
"l%Iy fi
simply
the per
Columbia, Ph:
phone, H.M
mention only a
fit Exide Batte;
Batteries for H.
Wireless Magazine.
August. 1933
simply amazed at
the performance"
(Sgd.) C.J.D., Weaste
Ortecx
be ecie
DRY BATTERIES
FOR WIRELESS
for H.T.
efflrkarlikfrerre Exide Service Stations and all reputable dealers. Exide Service Stations give service on every make of battery
Exide Batteries, Exide Works, Clifton Junction, nr. Manchester. Branches: London, Manchester, Birmingham, Bristol,
Dx zoi
G1asnow, Dublin and Belfast.
Better service results from mentioning
"
Wireless Magazine
7
"
when
writing to advertisers
Wireless Magazine,
August. 1933
VAWORLDS BROADCAST
W"-
Wavelength
13.93
13.95
14.47
14.87
14.97
15.576
15.81
15.625
15.82
15.86
15.93
16.10
16.26
16.3
16.36
16:38
16.39
16.56
16.57
16.68
18.72
16.76
16.81
16.85
18.878
1686
16.89
17.38
17.44
17.51
18.37
18.4
18.44
19t3
19.36
19.58
19.61
19.64
19.87
19.68
19.72
19.8
19.737
19.815
19.84
20.0
20.13
20.3
20.49
20.5
20.7
20.97
21.53
21.62
21.83
21.93
22.26
22.4
22.58
23.28
23.7
24.41
24.9
25.20
25.24
25.27
25.284
25.34
25.38
25.4
25.42
25.45
25.51
25.532
25.57
. 5 6 fl
26.39
25.72
28.83
27.5
27.65
`28.28
28.5
28.83
28.98
29.04
29.13
29.58
30.0
30.0
WAVELENGTH'
BritishI '
'
Dial
Name of Station
Readings
...
...
...
...
...
...
...
...
...
-_
...
...
...
...
...
...
...
...
United
United
United
United
..
Java
NS W
Java
United States
Belgian Congo
Japan
United States
Bolivia
United States
United States
France
United States
Wavelength
j
81'
t
31.297
31.31
31.35
31.38
31.48
31.545
31.55
31.58
31.6
31.7
31.71
31.88
32.28
32.71
32.93
33.59
34.68
35.55
36.92
37.80
38.07
38.476
38.65
39.58
39.74
40.5
40.54
41.1
41.6
...
...
...
...
...
_-
_-
45
45.31
45.38
45.5
46.67
46.69
46.7
46.73
Mexico
United States
------ --
W9XAO
Wayne W2XE
...
Rome 2RO
Bowmanville VE9GW
Boston WIXAL
...
Zeesen DJD
(I11.)
Italy
----
...
...
...
...
Constantine FM8KR
Rio Samba PRADO
Moscow REN
..
Bucharest
London (Ont.) VE9BY
Boundbrook \V3XL ...
Newark W2XA1
...
Minsk RW62 ...
...
...
...
Casablanca CNBMC
50.28
51
52.7
54.52
56.9
57.03
58.3
58.31
60.3
Java
Germany
Japan
Switzerland
Holland
China
Canada
United States
United States
_--
---
Canary Isles
Sts. Settlements
United States
United States
United States
Germany
Spain
Tunis
Ecuador
...
...
...
...
...
...
...
...
...
...
..
United States
Argentine
United States
United States
Argentine
...
49.96
Morocco
......
Canada
Great Britain
Holland
France
United States
United States
Great Britain
United States
United States
Java
48.35
48.54
48.8
48.88
48.9
48.92
48.95
48.98
49.0
49.02
49.08
49.1
49.18
49.22
49.3
49.34
49.4
49.43
Morocco
United States
United States
Great Britain
Costa Rica
Portugal
United States
New South Wales
Great Britain
Switzerland
United States
Germany
United States
Great Britain
Victoria
Brazil
Poland
Brazil
United States
Country
Congo
Kootwijk PDM
Shanghai XGD
Calgary (Alb.) CKS ,.
New Brunswick WEN
New York WEM
Amateur Band
..
Las Palmas EAR58 ...
48
United States
United States
Canada
Hungary
United States
United States
Canada
Canada
United States
Germany
Great Britain
Holland
France
Canada
Uruguay
Brazil
Madeira
Holland
Germany
United States
New South Wales
Madeira
Argentine
Belgium
Argentine Repub.
Congo
Argentine Repub.
Spain
Leopoldville ...
Lawrenceville (N.J.) WQN ...
Lawrenceville WOF ...
Rugby GCA
...
Heredia T14NRH
Lisbon CTIAA
Philadelphia W3XAU
Sydney VK2ME
43.11
44.51
44.61
44.91
Germany
'_____- Great Britain
Italy
Canada
Philippine I.
United States
United States
Dial
Readings
Name of Station
30.2
30.4
30.77
30.89
31.0
31.25
USSR
States
States
States
States
Holland
United States
Holland
Great Britain
Germany
Germany
Venezuela
Hungary
...
...
Amateur Band
...
Rocky Point (N.J.) WIK
Rocky Point (N.Y.) WIY
Drummondville CGA
Szekesfehervar HAT...
...
Rocky Point WMA ...
...
Rocky Point WMA ...
...
Drummondville CGA
...
Radio Maroc (Rabat)
Drummondville VE9AP
Rugby GBV ...
...
...
Kootwijk PDV
...
...
Pontoise FYA
...
..
Chicago W9XF
East Pittsburgh (Pa) \VISX 1:
Chicago
Java
Java
...
CGA
Manila KAY
Rocky Point-WQV
Deal (N.J.) WND
Chapultepec XDA
Rocky Point WKJ
United States
Belgium
Argentine
United States
Great Britain
Columbia
Holland
United States
Great Britain
Venezuela
...
...
Lawrenceville WLO-WLK .
Leopoldville ...
...
...
Kemikawoa (Tokio) JIAA ...
Schenectady W2XAD
...
Drummondville
United States
United States
Argentine
United States
Belgian Congo
Brazil
...
...
...
...
...
Boundbrook WIXAL
...
Eindhoven PHI
...
Daventry Empire GSG
...
Knigswusterhausen DJE ...
Norddeich DAN
...
...
Maracay YVG
...
...
Budapest HAT
...
...
Sydney VLR ...
...
...
Kootwijk PCL
..
Country
U S S R.
Roumania
Canada
United States
United States
USSR
Morocco
Colombia
China
Canada
United States
F.M.S.
United States
Venezuela
Canada
Sth. Africa
United States
Venezuela
Br India
United States
Canada
Bolivia
United States
Denmark
British Columbia
United States
Cuba
United States
Kenya Colony
Great Britain
Nova Scotia
Austria
United States
United States
United States
Germany
Canada
S S.R.
._U
DJC
Drummondville VE9DR
Moscow RV59
Rome (Vatican) HVJ
St. Denis
...
...
Tananarive FIQA ...
New York W2XBH ...
Knigswusterhausen DTG ...
Rocky Point WQN
Bandoeng PMY
Prague
Long Island (N.J.) W2XV
Italy.
Reunion
Madagascar
United States
Germany
United States
Java
Czechoslovakia
United States
Continued on page (0
Wireless Magazine.
August. 1933
N EW
"SENIOR" MODEL
LOUD SPEAKER
PARTRIDGE
of handling a large
input without distortion. Supplied
complete with Unit, base and
Ransformer,
giving
Ratios of 11.1 and 22.1.
It is capable
LONDON, W.C.I
PARK,
Mus. 5070
LEICESTER
PRICE
ON REQUEST
"PARMEKO" WORKS,
AYLESTONE
FREE
COLVERN
YOU SHOULD CHOOSE
FERROCART COILS
this Camco
COLVERN
.
Radio -Gram
always associated
CABINET
coils.
the outstanding
FERROCART Coils
are synonymous for
under
licence from
Made
the patentee,
Hans Vogt.
TYPES FI F2 F3
receivers
37/6
5O/-
per set.
C A R RI NG T O N
Manufacturing Co Ltd,
Showrooms : 24 Hatton..
Garden, London, E.C.1.,
Holborn 8202.
Works S. Croydon.
per set.
COLVERN LIMITED,
ROMFORD, ESSEX
Wholesale Depot,
London
150
of
-it's FREE.
Name
Address
12 W.M
"
Wireless Magazine
9
"
advertisements
Wireless Magazine.
August. 1933
length
62.56
66
67.65
70.17
70.2
79.5
84.5
92.31
208.3
Doeberitzr,
...
Liege (Wallonie)
r Magyarovar ...
Pecs
209.8 {
...
...
...
...
...
...
Miskolcz
211.3
Newcastle
...
214.3 { Warsaw (No. 2)
Aberdeen
214.9
Antwerp
...
...
215.6
Chatelineau ...
...
217
Knigsberg
218
Salzburg
...
...
218.5
Plymouth ...
...
220
Beziers
223.2
Swedish Relays
...
224
Cork ...
225.9
Fcamp
227.4
Flensburg
...
230.6
Malmd
281.3
Kiel ...
...
...
235
Lodz ...
...
...
235.5
Kristianssand...
236.2
Bordeaux-Sud-Ouest
257.9
Nimes ...
239
Nurnberg
240.1
Stavanger
242
Belfast
244.1
Basle ..
Linz
...
...
245.9
Berne
247.7
Trieste
...
...
249.5 { Juan-les-Pins
Prague (No. 2)
250
Radio Schaerbeeck
250.9
Barcelona EAJI5
...
253.1
Glelwltz
...
...
254.7
Toulouse PTT
256.7
Hdrby...
...
...
259.8
Frankfurt ...
...
2616
283.8
285.7
267.4
269.8
271.2
271.5
273.7
276.5
280
281
282.2
Dial
Name of Station
f London National
Morayska Ostrava
Lille ...
( Valencia
Bremen
l $art
Ceinte -Lige
Rennes
...
...
"
"
Lisbon CT1AA
Berlin ...
Ibur
}r
...
...
Canada
United States
Germany
...
...
...
...
___
_
...
United States
U.S.S.R.
South Africa
Germany
Germany
Belgium
Hungary
__Hungary
...
...
...
...
...
...
...
...
...
...
284.3
Radio Lyons ...
286
Montpellier ...
288.3 { Bournemouth...
Scottish National
291
Viipuri...
298
Kosice
...
293.7
Limoges PTT
298.1
Hilversum ...
298.8
Tallinn
...
301.5
North National
304.3
Bordeaux PTT
308.8
Zagreb...
...
307
Falun
308.5
Vitus-Paris
309.9
West Regional.
312.8
Cracow
313.9
Genoa ...
...
315
Marseilles
...
1.Naples
...
818.8
Sofia.
.
1
319.7
Dresden
...
321.9
Goteborg
325
Breslau
...
328.2
Poste Parisien
Milan
381.6
...
335
Poznan
338.2
Brussels (No. 2)
341.3
Brno ...
...
346.2
Strasbourg ...
348.2
Leningrad
...
348.8
Barcelona EAJ1
362.1
Graz ...
...
368
Tlraspool
..
355.9
London Regional
459
461.5
465.8
472.4
476
480
483
488.6
405.9
500.8
501.7
509
509.3
517
525
533
540.6
541.5
550
France
Czechoslovakia
Belgium
Spain
Germany
France
Sweden
Germany
Great Britain
Great Britain
Czechoslovakia
France
Spain
Germany
-- --_
...
...
...
''
Italy
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
..
...
.-.
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
..
...
...
...
...
...
...
...
...
...
...
...
..
..
Lvov .
...
Radio Toulouse
Statino...
...
Leipzig
...
...
Katowice
Athlone
...
...
Radio Maroc
Berlin
...
Madrid (Espana)
l Madrid EAJ7
Belgrade
..
f1 Makhatch-Kala
Stockholm ...
Rome ...
...
Parts PTT ...
Beromuenster
Archangel
...
Lyons PTT
Gorky
Astrakhan
Brussels No.
...
...
...
...
Palermo
Sundsvall
Budapest
...
( Tampere
Augsberg
Wilno
Hanover
Freiburg
Grenoble
Ljubljana
Czechoslovakia
Bulgaria
Germany
Sweden
Germany
France
Italy
Poland
Belgium
Czechoslovakia
France
U.S.S.R.
Spain
Austria
U.S.S.R.
Great Britain
2,850
10
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
_I
--____
I
__
France
Dantzig
Austria
U.S.S.R.
Norway
Italy
...
...
...
...
..
...
...
__
...
...
...
...
...
...
...
___
...
Ostersund
...
...
Petrozavodsk RV29 ...
Heston Airport
...
Budapest (2)
...
Leningrad
...
..Kharkov
...
...
Eiffel Tower
...
...
...
...
...
...
..
...
...
...
...
...
...
...
...
...
...
...
U.S.S.R.
U.S.S.R.
Belgium
Austria
Latvia
Germany
Italy
Poland
Germany
Germany
France
Yugoslavia
...
...
...
...
...
...
...
Italy
Hungary
Finland
Germany
Germany
..-
...
...
...
...
...
...
...
...
...
...
...
Spain
Switzerland
U.S.S.R.
France
Germany
U.S.S.R.
Great Britain
U.S.S.R.
Czechoslovakia
Norway
Sweden
LaMoscow
Geneva
Norway
Finland
U.S.S.R.
Spain
France
Germany
Great Britain
Poland
France
U.S.S.R.
Germany
Roumania
Great Britain
Switzerland
Poland
Irish Free State
North Africa
Germany
Spain
Spain
Yugoslavia
U.S.S.R.
Sweden
Italy
...
...
...
...
...
...
...
...
...
Italy
...
...
...
...
...
Country
Germany
North Africa
Norway
...
...
...
...
...
Italy
...
...
...
...
...
...
...
...
...
...
...
...
...
...
779.2
833
840
857.1
937.5
1,000
Moscow
1,060
Scheveningen -Haven
1,071
Tiflis ...
...
...
1,083
Oslo ...
...
...
1,107
Minsk ...
...
1,153.8
Kalundborg
...
1,140
Monte Ceneri (tests)
1,190
Luxemborg
...
Reykjavik
...
...
1 200
1 Istanbul
...
...
1,229
Boden ...
...
...
1,237
Vienna
...
1,304
Moscow
...
...
1,354
Motala
...
...
1,380
Novosibirsk ...
...
1,411.8
Warsaw
1,445.7
Paris (Eiffel Tower)
1,481
Moscow (RV1)
...
1,538
Ankara
...
...
1,554.4
Daventry National
1,634
Knigswusterbausen
1,725
Radio Paris
...
1,796
Lahti
...
...
1,876
Hufzen
...
...
1,910
Svendlovst ...
...
1,935
Karmas
...
...
2,825
Kbnigswusterhausen...
France
...
750
770
Italy
_____
...
Munich
Riga
Germany
France
France
Great Britain
Great Britain
-----
...
...
...
...
...
...
...
Vienna
563
566
669.2
569.7
574.7
Yugoslavia
Sweden
France
Great Britain
Poland
----
...
...
Germany
Czechoslovakia
Denmark
Portugal
Germany
__----_'
...
...
Langenberg
Simferopol
North Regional
Ivanovo-Vosnesensk...
Prague
...
...
Trondheim ...
...
Florence
...
559.7 {l Kaiserslautern
France
Holland
Fsthonia
Great Britain
France
_-__-
...
Belgium
France
Finland
!
..
Bucharest ..
..
Midland Regional ...
Sottens
...
...
Austriaerm680
720
Germany
...
...
...
...
...
...
Klagenfurt ...
Odessa...
453
{ Porsgrund ...
453.8
Milan Vigentino
456.6
San Sebastian
Italy
...
Magdeburg
Stettin
...
...
450.3
Italy
...
...
Helsinki
Kharkov
Seville
Radio LL
Frederikstaad
...
395.2
398.9
403.8
408.7
411
418
419.5
424.3
430.4
435.4
441.2
447.1
...
Hamburg
385
385
389.6
France
France
Germany
Norway
Ireland
Switzerland
Austria
Switzerland
..
...
...
Algiers
Bergen
Bolzano
NorwayDantzig
...
...
...
3681
Poland
Great Britain
Belgium
Belgium
Germany
Austria
Great Britain
Belgium
Sweden
Irish Free State
France
Germany
Sweden
Germany
Poland
.. .
Mnhlacker ...
((((
370.1
372.2
376.4
381.7
Dial
Readings
Name of Station
360.6
363.6
365.5
367.5
Hungary
Great Britain
-.
Turin
Heilsberg
Bratislava
Copenhagen...
283.6 {
...
:..
Wavelength
Country
Readings
Contougeed8from
U.S.
U.S.S.R.Swizerland
R.
_ __
---
Switzerland
Sweden
U.S.S.R.
Great Britain
Hungary
U.S.S.R.
U.S.S.R.
U.S.S.R.
Holland
U.S.S.R.
Norway
U.S.S.R.
Denmark
Italy
Luxemburg
Iceland
Turkey
Sweden
Austria
U.S.S.R.
Sweden
U.S.S.R.
Poland
France
U.S.S.R.
Turkey
Great Britain
Germany
France
Finland
Holland
U.S.S.R.
Lithuania
Germany
France
Wireless Magazine.
August. 1933
Radio's
Best,
for
F.17.6
Complete
Ml
SUNBEAM
See
(page 76).
MODEL
sf
37
6: 17: 6 Complete
The Sunbeam B.37 is only obtainable
the
..
tie
SEIFPAD
MEtAIi011
are
\I,
IA
t@N1NiW12em i'
11111l111111111! 1111
,vtiwiwehl
A "PRESENT" for
the "UTUR ."
82, YORK
SIGNAL CO.
LTD.,
"
Dubilier Condenser Co. (1925) Ltd., Ducon Works, Victoria Rd., North Acton, W.3
Wireless Magazine
advertisements
Wireless Magazine,
August.1933
1
ithw
of the Latest Catalogues
CATALOGUES!
:-
bearingen-
...
A FEW WORDS
!
HERE's a folder from Wilburn
and Co. They call it A Few
Words About Condensers.
Fairly
too, even if they are
more figures than words. It deals, of
course, with Peak condensers and is
just the sort of thing you'll like to
have by you when building or
renovating a set.
It's the very latest Peak production
and deals with the new type W
electrolytic condensers.
By the way, I wonder if you know
that Wilburn make some very useful
little 5-, 6-, and 10 -way connectors
of bakelite,
having
moulded in brass insets which are numbered.
These too, are described in A Few
Words.
331
332
have lists of
mains transformers and smoothing chokes by you in the wireless
den, but most thin paper charts get
torn all too easily. So Rawswood
deserve a note of congratulation
on their latest data sheet of mains
transformers and smoothing chokes.
It is a comprehensive folder, giving
practical and technical details, enclosed in a stout cardboard cover.
.
.
.
Rawswood make very good power
apparatus and this folder includes a
FULL O' POWER
description of three fine complete
seems to me that class B and
power packs, as well as details of
have given a new lease of
Q.P.P.
power transformers, filter chokes, and
life to the dry battery as a provider of
low -frequency transformers.
high tension. If you have a really
.
.
.
good battery you can, with a modern
ENTERPRISING IGRANIC
set, get amazingly economical runIGRANIC are catering for the up- ning and yet have an undistorted
to-date amateur in a very whole- power output of about 2 watts.
hearted fashion. Seems to me that
But you must have a good battery.
almost every other day I get a Ieaflet Siemens, as one of the oldest elecdescribing some new component trical firms in the industry, can
which Igranic have just put on the certainly claim to make good batmarket.
teries, and so I was particularly
For instance, here are the latest interested to get their latest folder
Igranic sheets before me as I write- and see how they have dealt with the
three of them. There is a new Igranic class -B question.
class -B driver transformer, costing
In the very wide range of types
only 1ls. 6d. It has a number of they make a triple -capacity power
terminals, so that the secondary is battery recommended for sets taking
tapped and two alternative ratios are 10-20 milliamperes for class -B
provided, 1 to 1 and 1.5 to 1.
receivers. There is a double -capacity
Then there is the CH4 choke, power battery also suitable if, on
which costs only 9s. 6d.
account of bulk and weight, the
The third Igranic folder is devoted triple -capacity type is unsuitable.
to something which will interest the
Anyway, if you get the new
keen experimenter-a buttonhole Siemens folder you will be able to
transverse -current microphone.
I see the voltage ranges, dimensions,
won't go into details as all techni- weights, types, and prices of all the
calities are given in the folder.
Siemens batteries.
335
IT
333
334
12
336
Tl
is
th
b
b
a<
ar
P'
ir
tl
d
s
a;
Wireless Magazine,
11.12
August. 1933
ONLY SPEAKER
Specifedfoihe
WIRELESS MAGAZINE
'AC/DC
THREE11
Only the best was good enough for a set like this. The best
speakers in the world are Blue Spot-and so 99 P.M. was
chosen by the designers to ensure perfect reproduction.
TECHNICAL DETAILS
QQPM
SQ'6
Catalogue W.M. 30.4. gluing Pell Blue Spot range .vent pent Ires on request
PURITY
DEPENDABILITY
ECONOMY
is
Unit
and
is practically
indestructible,
will give at least twenty years'
alkaline electrolyte.
It is
left faithful service. Five -year -old units
permanently coupled to the L.T. (some of the first made) are working
accumulator and recharges itself better to -day than when new.
from this automatically and without
Have done with replacement and
wasting a milli -watt of current, recharging expenses. Enjoy pure
merely by turning a switch. The reception for a lifetime.
Fit a
Unit is always on charge when the Milnes Unit and finish with H.T.
receiving set is not in use. Con- troubles for ever.
sequently it is always fully charged,
Ask your radio dealer, or send the
and equal to the demands of the coupon for Free descriptive book.
N GT. BRITAIN.
90 volt ... 3 3 0
ZOO volt
...
3 9 5
120 volt
4 2 3
...
150 volt
5
6
...
Hire Purchase terms available
PRICES
obligation.
Name
Address
V.I.
Keir Dawson-Bradford
"
saw
13
it in the
Wireless Magazine
'
"
Wireless Magazine.
August, 1933
Reg.
Trade Mark
IRON
Patents
pending
NUC L
er
31376/32,
15746/33,15747/33
31377/32,
are
CORE
COILS
for the
essential
REPORTS are to hand of the amazing performance of the " Tyers Iron -core Three." The
faith of the designer in the new Wearite Coils has
been amply justified.
Never before has such an
efficient combination of range, selectivity, and
perfect reproduction been attained.
Build this
wonderful set and realise what the combined
efforts of Mr. Paul Tyers and the Wearite manufacturing organisation have done for better radio-
for you!
BETTER
BAND
- -
SELECTIVITY
WIDER WAVERANGE
PERFECT MATCHING
Type B.P.I
Type B.P.2
Type T.G.
12/6
12/6
12/6
USED
FOUR
"
One Wearite T.21A Mains Transformer Price 25/ (Reg. Design 780272)
Price, each,
10/6
WEA
WRIGHT
&
Reg.
Trade Mark
"
Wireless Magazine
I1
"
'Phone
Tottenham 3847/8'9
Q 3233
Wireless Magazine,
GYL1HDtZ:cf:
SPHERICAL
LEN:u
August. 1933
STAGGEREj RIGHT
AH&LEO PRISM
(ELHELott Ct.vICE)
LEtt&
OBJECT
FIELD
LEtt
By means of a special
Negligible Power
He has done away with the
unwieldy Nipkow disc and the
heavy mirror drum and substituted
a tiny thing which looks like a crystal
"Scophony."
In the following pages a special
correspondent discusses the basic
features of the Scophony television system and has something
to say about the possible form
the receiver will take.
1933
required for
other vi olds.
'
re
E
Ina
n
1
Fig. 2.-How the echelon device staggers the horizontal strips into what
amounts to a single straight line that can be easily scanned by an oscillating mirror
mechanically
moving parts,
and therefore
no inertia, so
that when used
for scanning it
is free from
the narrower
Any imag
seen in t\
instance, tl
But if the F
optical gr:
each of
marked a
be displa
they fall
line, as sh
By A Special Correspondent
second gives
vision.
No Moving Parts
This is done without the use of any
moving parts or mechanism. Once the
Sin
In othe
picture h
formed
speaking
this born
complet(
lateral
as the sc
The
division
course,
desired
suitabl:
" steps
The
resole
more
the t
passe;
centra
If
line,
point
th
al
tl
Wireless Magazine.
August. 1933
required for " living " pictures; in representative of the whole picture. axis under the control of a chronoother words, fifteen cycles per
In Scophony television, therefore, meter spring S.
second gives complete persistence of there is no necessity for using the
The " drive " control, for synvision.
comparatively large rotating disc chronising and for limiting the
Any image or picture is naturally typical of ordinary systems. In fact, amplitude of swing to a steady value,
seen in two dimensions, as, for the moving parts of the apparatus is applied through a cross -pivoted
instance, the area shown in Fig. 1. can, as Capt. Robinson points out, rocker R, which is coupled to a shaft
But if the picture is reflected from an be carried without
optical grating or echelon mirror, discomfort in one's
each of the horizontal sections pocket.
marked ab, cd, ef, and gh, will
In transmission
be displaced relatively, so that the picture, after
they fall more or less into a single being converted into
line, as shown in Fig. 2.
its " line " equivalent, is scanned by
Single-line Equivalent
the vibrating mirror
In other words, a two -dimensioned which throws the
picture has been automatically trans- consecutive light formed into what is, practically and -shade values in A
speaking, a single -line equivalent. In sequence across a
this form the complete picture can be photoelectric cell or
completely explored by a single
eye," so as to
lateral movement of a mirror used transform them into
as the scanning device.
corresponding elecThe number of horizontal sub- tric currents. After
divisions ab, cd, etc. (Fig. 1) can, of suitable amplificacourse, be increased to give any tion, these are used
desired degree of definition by to modulate the outsuitably increasing the number of going carrier wave
" steps " on the reflecting mirror.
from a transmitter.
In reception, the
Fig. 4.-A device developed by G. W. Walton for driving
Average Centre
and synchronising his vibrating mirror. It is likely that
process is reversed.
such a mirror could be used instead of a rotating drum
The actual appearance of the The light from a
or disc in picture reproduction
resolved picture " line " is perhaps lamp is swept by
more clearly shown in Fig. 3, where a vibrating mirror
the track of the scanning mirror across the face of a stationary T connected to the armature of a
passes diagonally across the average "stepped" mirror, which automatic- synchronous motor M.
centre, as shown by the lines ss.
The resultant motion of the mirror
ally restores the picture into its
If one considers a typical vertical original two-dimensional form.
may be adjusted so as to compensate
line, such as xx, in Figs. 2 and 3, any
One method described by Mr. for the brighter edges of the " line "
point along that line will represent Walton for driving and synchronising picture so as to ensure a uniform
illumination.
The drive may be arranged so as to
give a " saw -tooth " wave motion to
a spot of light reflected by it from the
X
lamp, thereby adapting the instrument to receive the standard type of
picture transmission.
The necessary phase -control reB
A
quired for perfect synchronisation is
obtained by rotating the platform r
C
D
X
carrying the stator of the motor M.
E
Receiver Possibilities
It is not at present certain how far
Fig.
3.-Appearance of the resolved picture " line." Compare with the staggered strips
of Fig. 2. The track ss represents the ""average" centre of all the lines
Wireless Magazine,
August, 1933
BERLIN
FRANKFURT
SWIRERIND
OWlfI1 I
AffecYVo
ALAN HUNTER
Every listener has heard
of the
Three Groups
Three kinds of wavelengths figure
under the Lucerne Plan; Exclusive,
National Common, and International
Common, the last category being
further sub -divided into Types One
and Two according to the power.
By these various means it has
been found possible to find room for
no less than 232 stations, which will
Wireless Magazine.
work on 130 channels, only 55 of
which are exclusive. Fortunately,
most of the worth -hearing foreigners
are among these exclusives, so there
will be plenty of programmes clear
of mush-if the rest of the plan
works out, anyway !
Power of transmission has been
an important factor in the new
wavelength distribution. Medium wave stations are limited to 100
kilowatts, except where stations of
120 kilowatts already exist or are in
process of being built, such as
Prague, Vienna, Budapest, Leipzig,
Rennes PTT, Toulouse PTT.
On the long waves power is
limited to 150 kilowatts, exception
being made for Moscow No. 1,
which, for some extraordinary reason,
insists on having 500 kilowattsperhaps to tell us how the second
Five Year Plan is getting along ?
Modulation Question
Wrapt up in this power limitation
is the question of modulation, of
course. In the past we have suffered
a great deal from stations of high
power over -modulating, particularly
on speech, producing that all-too familiar whispering sound known as
" sideband splash."
High power is not in itself impossible to cope with at the receiving
end, but over -modulation of high power stations presents insuperable
difficulties, even for a super -selective
super -het.
It is therefore a good thing
that under the Lucerne Plan
modulation must also be restricted-or the International
Broadcasting Union " policemen " will tell the offending
countries all about their evil
deeds
National Common wavelengths must be limited to 5
kilowatts and International
Common wavelengths to 2
kilowatts for Type 1 and .2
kilowatt for Type 2.
The success of the new
}dan depends to a very large
degree on the strict observance of wavelength allocations.
Tolerances allowed by Lucerne
are much more severe than in
the past. For example, stations
on exclusives may vary only
50 cycles one way or the other,
while stations on shared wavelengths must keep within plus
or minus 10 cycles!
Looking through the official
!
:-
August, 1933
:-
Effect of Droitwich
This list reveals the true import
of Droitwich, the coming of, which
will close down London, North and
West Nationals, redundant with the
high -power long -wave National signal covering the whole of the
country.
It also shows three new stations:
North-eastern Regional, which is
designed to serve the populous
Tyneside districts not adequately
covered by North Regional:
then there is North Scottish
Regional, to placate
the
unceasing agitators of the
North of Scotland, who
have rightly complained of
bad service from Scottish
Regional; and lastly there is
North Ireland Regional, which
will be the high -power successor to Belfast.
Plymouth, by the way, will
go up to 5 kilowatts and will
serve the west in parts not
well reached by West Regional.
Within the next year or
thereabouts, then, we are in
for two ether upheavals; firstly,
the general re -shuffle with the
rest of Europe next January,
and secondly, in about a
year's time, another
rearrangement to meet the
changed conditions brought
about by the opening of
TAKING A RESPITE IN THE LOUNGE
Droitwich.
Two of the British representatives taking a rest from the
conference in the lounge of the HotelNatlonale at Lucerne.
A full calendar for ether
They are Admiral Sir Charles Carpendale (in the background) and Noel Ashbridge
searchers !
19
Wireless Magazine.
71/
August. 1933
'ell
AC
12 EIE
(16
Lf'
(11049
Designed by the "Wireless Magazine
IN
proposition.
When the
change -over
is
made there
will he no need
to make drastic
alterations in
the design of
the set, which
gives the same
results whether
run from A.C.
or D.C.
"
Technical Staff
that will work from all kinds of mains; knowing that the
need existed " Wireless Magazine " has taken the first
opportunity of designing a really satisfactory receiver
for the job.
By means of a compromise it has been possible to
make A.C.-D.C. sets for some time past, but we have
waited until a proper range of A.C.-D.C. valves became
available. The valves actually used in our original set
are foreign; an announcement of the production of
British A.C.-D.C. valves appears on page 32.
Then there
large num-
is a
ber of people
who, for one
reason or
are
another,
constantly
20
Wireless Magazine.
August. 1933
1.D0Ctl
Spiro
5.0000
EACH
IMFO
so.000n
RFC.
X.F.C.
!I
RECT.
Lh
'0003
0003
3g
OI
.000t
0005
0005
6B
2exD.
1r
a
INED
ar
5.000
GANGED
IpOa
POWER
TYPE H.F(;
^o
50.000
ooQ7oe
200/250K
RE515t
RCDRAL
LAMY
Oa
5vF0
Pll
20E0.
Mains Smoothing
50000
condenser. Reaction is controlled by a .0005 -micro farad variable condenser and a fixed condenser of
.0003 microfarad is used across the anode and cathode
to improve the detector efficiency.
Between the detector and the power valve is the
usual low-frequency transformer coupling, the primary
21
T
Wireless Magazine.
August. 1933
th.
83
br;
sh,
ba
th(
al'
CE
t4
bl
pi
tri
gz
w
WITH THE VALVES IN POSITION
U:
C(
o
a
ri
(t
r
w
ri
e,
si
value.
lE
Mains Interference
Accessible Components
The actual construction of the set
is not at all difficult, although at
first the layout may appear to be
In point of
somewhat cramped.
fact, however, it will be found that
the parts are all quite accessible.
Although a quarter -scale layout and
wiring diagram appears alongside.,
many readers will prefer to work
from a full-size blueprint. One of
these is obtainable for half price,
that is 6d., post paid, if the coupon
ki
tl
t:
0
t
r
r
Wireless Magazine.
that tl e connections numbered 81,
83 and 85 are made with metal braided flex. The metal braiding
should in each case be turned well
back from the actual wire and should
then be earthed.
There are five control knobs in
all on the front of the set, that in the
centre being the dual knob of the
two -gang condenser.
Fine-tuning Device
The main part of this knob adjusts
both sets of vanes, but the smaller
projection in front actuates only the
trimmer, so that the . set can be
ganged up on any particular station
without any trouble.
The front
knob, in other words, is simply
used as a fine-tuning device.
On the left of the main tuning
control, arranged one above the
other, are the volume control (top)
and wave -change switch. On the
right are the reaction condenser
(top) and the gramo -radio switch.
Nobody will have any difficulty about
working these controls to get the best
results from the receiver.
Console or Radiogram
It will be noticed from the photographs that the set lends itself
equally well for construction as a
simple table model with built-in
loud -speaker or as a complete radio
gramophone with a universal motor
that works from A.C. or D.C. mains.
There may still be some readers
who do not appreciate the fact that
this set can be used on either A.C.
or D.C. mains without ar_y alteration
whatsoever, provided that the voltage
is between 200 and 250 volts.
As long as that condition is met
there will be no trouble and the
receiver will give perfect hum -free
reception wherever it is used.
August, 1933\
(or
... 1
...
...
CHOKE, LOW-FREQUENCY
I
-Parmeko,
type A40/51)
Davenset, Wearite)
...
COILS
s. d.
... 0
...
...
CONDENSERS, FIXED
1-T.C.C..0001-microfarad, type 34
(or Graham-Farish, Telsen)
1-T.C.C..0003-microfarad, type 34
(or Graham-Farish, Telsen)
..
1-T.C.C. .003-microfarad, 1,000
D.C. test (or Dubilier)
..
1-T.C.C..000-microfarad, type 34
1-T.0 C
.01-microfarad, type 40
(or Dubilier)
..
1-T.C.C. 05-microfarad, type 40
(or Dubilier)
...
...
...
1-T.C.0 .01-microfarad, 1,000 volt test (or Dubilier)
..
2-Peak 1-microfarad, type A4
(or Lissen, Telsen)
..
2-Peak 2-microfarad, type A4
(or Lissen, Telsen)
...
...
1-T.C.C. 2-microfarad electrolytic,
200 -volt, type 561
...
...
2-Peak 8-microfarad electrolytic,
type W, with holders (or T.C.C.,
Dubilier)
..
..
..
1-T.C.C. l0-microfarad electrolytic, 50-volt, type 521 ...
...
010
CONDENSERS, VARIABLE
1-Polar
0 19
0 10
Pick-up (2),
Clix, Eelex)
L.S}, L.S....
...
(or
... 0
Advantages
of
IT
according
to
whether speech or
music is being transmitted. The chief
thing with speech
is to have it as
clear as possible.
But with music, all
I can say is that
some people seem to
like a lot of bass and
SPACE FOR STORING GRAMOPHONE RECORDS
Here Is the set assembled as a complete radio gramophone. Note others want a fair
at
each
end
of
the
motorboard
there
slots
that
are
for storing
amount of treble.
records
23
d.
8
...
RESISTANCES, FIXED
10-Erie, 1 -watt type, values 760,
RESISTANCES, VARIABLE
1-Preh 5,000 -ohm potentiometer,
standard type with knob (or
Lewcos, Watmel)
,,,
...
SUNDRIES
SWITCHES
1--S8B6ulgin
1
1
TRANSFORMER, LOW-FREQUECY
0 11
2 10
ACCESSORIES
'CABINET
1-Osborn table model, type 300...
LOUD -SPEAKER
1-Blue Spot permanent -magnet
19
14
10
10
6
6
0
6
17
...
Tone Control
When a tone control is fitted, the
user has the means for best adapting
the output to suit his conditions.
The bass can be strengthened or
speech can be made more clear,
perhaps, by strengthening the treble
notes and so on.
Not many sets have a useful
The
tone -control arrangement.
general idea of connecting condensers across a loud -speaker is
not very satisfactory, and is rather
wasteful.
It is much better to include
immediately after the detector a
device by means of which the tone
may be adjusted, and in this
connection a proper transformer and
tone -control potentiometer (such as
may now be obtained) is of
considerable value.
The position in which a tone
control is connected is obviously a
matter of some importance, as it is
wasteful to amplify notes which are
afterwards reduced in strength.
W. James.
Wireless Magazine,
August. 1933
,
,
24
Wireless Magazine.
WITH
television,
the
tele-
and use.
Last month we discussed the
general principles of photoelectric
devices and some of their characteristics. This month I want to
describe to you some practical
experiments of an interesting nature
which you can perform with apparatus well within the reach of the
average amateur.
Electric Variations
It will have been gathered from
last month's article that, no matter
what form the photoelectric cell may
take, its purpose is to provide, in a
suitable circuit connected with it,
variations of voltage and current.
Most of the photoelectric cells in
use are not self -generating; that is to
say, they need some voltage source
connected to them. The action of
light on the cell controls the flow of
electrons across the space between
the two electrodes and thus causes
the cell to act as if it were a variable
resistance controlled by the light.
It is interesting in this connecton
to refer to Fig. 1, which shows how a
photoelectric cell can be connected
to the grid of a valve for magnifica-
tion purposes.
The anode of the cell is
connected to a tapping on the
high-tension battery and the resultant
electronic flow passes through the
August. 1933
NIGH
RESISTANCE
25
Wireless Magazine.
August. 1933
most interesting and practical experimental board consisting of their
photronic cell, a special sensitive
relay operated directly from the
current generated by the cell, and a
still larger relay operated by the
small one so as to bring into operation any apparatus desired (Fig. 2).
Small Battery
PNOTQonic CELL
SENSITIVE RELAY
Fig. 2.-Connections of the Weston photronic system. The photronic cell is of the left,
t he sensitive relay in the centre, and the power relay on the right
INPUT
(TRANSFORMER
Photronic Cell
For those who want comparatively
simple apparatus of the above type
for general photoelectric experimentation I can strongly recgmmend the
Weston photronic cell made by the
Weston Electrical Instrument Co.,
Ltd., whose meters are so well known
to all experimenters. There is a
very important difference between
26
Wireless Magazine.
August, 19331
i--ii
Cost of Cells
BAbeldete
Ati
Wireless Magazine.
August, 19331
CONDENSERS, FIXED
1-.0003-microfarad, upright.
2-.01-microfarad, upright.
2-2-microfarad.
HOLDERS, GRID -LEAK
RESISTANCES, FIXED
2-20,000 -ohm spaghetti.
1-50,000-ohm
spaghetti.
25-megohm grid leak.
1-.1-megohm grid leak.
1-2-megohm grid leak.
1-
3-Baseboard holders.
SUNDRIES
HOLDERS, VALVE
2-Four-pin.
1-Five-pin.
1-American type.
PLUGS AND SOCKETS
4-Wander plugs, marked:
G.B.+, G.B.-1, G.B.-2.
2-Spade terminals.
S-Large insulated terminals.
4-Terminal blocks.
H.T.+,
SWITCH
flash ceases.
The voltage then rises again and
Intervalve.
the occurrence is repeated. Directly
the flashing point is reached you
with a gramophone pick-up to see should withdraw the plug and reduce
that it works satisfactorily. This is the voltage so as to keep it below the
done by connecting two leads from flash point.
the pick-up to the same positions
As an example, with the potassium
as the secondary of the transformer cell referred to, the intermittent
is
pickin
input
f
labor;
ment
on a
or
simil
for y
in yl
1-Rotary on -off.
TRANSFORMER, LOW-FREQUENCY
1 -Standard
Y
wor:
kinc
cOv1
witl
the
whii
be e
A
livil
cur
ma
bri
of
gel
sh
Weston Experiments
You may also care to experiment
with the Weston photronic cell using
this amplifier.
In such a case,
T 1 PI CAL PHOTOCELLS
however, the connections will be
.l1 kinds of photoelectric cells
are
now available for experisomewhat different, although you
mental purposes, the prices
will use the American valve holder.
ranging from about 15s. upwards.
A large stock of cells of all kinds
The Weston cell, as previously
is kept by Electradix Radios, of
218
Upper Thames Street,
explained, has two pins, one thin
London, E.C.4
and one thick, which fit into a pair
of the holes in the American holder.
The Weston cell, as we have seen joined to the high-tension wander - glow started at about 170 volts and
above, is self-generating and of plug. Then, with light switched on with the R.C.A. caesium cell the
comparatively low resistance. For to the photocell, try various positions voltage was considerably above this.
this reason the two connections (one of the wander plug, starting at a
Cells usually have the most sensigoes to the plate pin and the other fairly low voltage, until you reach a tive point just below the flash point,
to the filament pin)
but it is not necessary
from the American
to get near to this figure
valve holder should be
in order to get very
taken to the primary
interesting experimenwinding of an ordinary
tal results. An ordinary
intervalve transformer,
125 - 150 volt battery
the secondary of which
will be found quite
should be connected to
suitable in the great
low-tension negative on
majority of cases.
one side and to the
When ordinary daylower input terminal
light is falling upon a
(that connected to the
photoelectric cell you
.01 - microfarad conwill probably hear
denser) on the other.
nothing at all unless
The wander plug for
you arrange some form
joining the high-tension
of interrupter to interbattery will not be
rupt the light reaching
used in such a case.
the photoelectric cell at
Before experimenting
an audible frequency.
with any of the photoEXP ERIIIENT.4L AMPLIFIER FOR PHOTO Cr.LL
This is as it should be,
This photograph shows the amplifier suggested by Percy W. Harris for
electric cells you can
and if the amplifier
simple pho toelectric experiments, which open up art entirely new field
test out the amplifier
for the amateur
hums, buzzes or howls
28
pl.
be
pl
w
Cl
lc
fi
t1
c
v
1
Wireless Magazine.
it is either unstable or you are experiments
picking up stray voltages on the which can be
input leHds.
done with it.
find it advisable in my own
T
If you want
laboratory always to carry out experi- an absolutely
ments of this kind with the baseboard steady source of
on a sheet of metal which is earthed bright light and
or else on a sheet of Konductite you are in a
similarly earthed, but you must find house with an
for yourself whether this is necessary
in your case.
current supplyin fact, wherever
Baseboard Covering
you are-an autoYou can do no harm whatever by mobile headworking on an earth plate of this lamp bulb or a
kind, and you can very conveniently motor -cycle headlamp complete
cover the underside of the baseboard with reflector will be found most
with copper foil, bringing it out to useful, as this can be run from an
the low-tension negative terminal, accumulator which will be comwhich, as I have said above, should pletely free from the slightest
be earthed.
fluctuation.
After dark, however, if you are
living in a house with an alternatingcurrent supply, you will have ample
material for experiment
Stand a
bright metal -filament lamp in front
of the photoelectric cell and you will
MANY people with battery sets
get a loud 100 -cycle hum, which
will be wanting to convert
should stop dead immediately you their output stage to class B in
place your hand or any opaque object readiness for the winter months.
between the source of light and the One of the best designed class -B
photocell.
converter units we have yet handled
Even flicking your
across it is that made by the Multitone
will be audible in the telephone Electric Co., Ltd., of 93/98 White
connected to the output or in the Lion Street, London, N.1.
By
loud -speaker if you are giving means of this unit, which can be
alternating
August. 1933
VERY SENSITIVE
PHOTOCELL
most sensitive of the
standard commercial cells is the
Weston photronic arrangement, seen
here complete with relays for controlling o power circuit
By far the
further amplification.
The next thing you may care to
try is a simple light box, which can
consist of any convenient tin which
will hold an electric lamp, and a
hole in one side of the box allowing
for the release of a beam of light
whenever desired.
Wireless Magazine.
August. 1933
may ten
at the
last month.
OW
COMPLETE SET
The Tyers Iron -core Three completely assembled in its C.A.C.
cabinet
designer, the
task of building and
successfully adjusting so
simple a set as a three valve receiver seems al- 7/
most child's play. This
is because one lives in a 100 per
cent. technical atmosphere all day
O a
band.
Mucl
depend
of the
lar, the
accoun
high;
suitabl
Shi
hatte.
60-vc
c.onn
thro
valu
find
are
Mu
Th
me
abl
ser
co
ae
w
tY
le
long.
Resistances, condensers, coils, and
valves literally surround one in
hundreds, and one grows accustomed
to handling them with just as little
apparent care as the window cleaner
runs up his ladder, or the bank
clerk counts his pile of silver.
receiver
r
t'
Wireless Magazine,
August. 1933
medium wave-
band.
Dropping Resistance
Should you by any chance use a
battery which is not provided with a
60 -volt tapping, the lead may be
connected to a higher voltage tapping
through a fixed resistance.
The
value you will, of course, have to
find by trial until the loudest signals
are obtained.
No doubt many of you will have a
Mullard PM12A of the plain type.
This may be used in place of. the
metallised type, and you will probably find that you will obtain greater
sensitivity but a little less selectivity.
The loss of selectivity can be
compensated for by using a lower
aerial tapping. In fact, to the reader
who lives very much in the heart of
the country, where selectivity is of
less importance, I would almost
recommend the use of the clear
type PM12A.
FINE RESULTS
Tests prove that the Tyers Iron core Three does everything that
a set with iron -core coils can be
expected to do
s.
0 8
d.
0
COILS
CONDENSERS, FIXED
3-T.C.C..0003-microfarad, type 34
1-T.C.C. .001-microfarad, type 34
1-T.C.C..002-microfarad, type 34
1-T.C.C. .02-microfarad, non -inductive type
...
...
0
0
3
1
... 0
0 1
0 10
0 7
9
6
6
9
8
0
0
in. panel
...
8 in.
...
by
... 0
9
0
6
0 10!
...
...
...
0 12
ACCESSORIES
BATTERIES
1-Ever Ready
1-Ever Ready
HOLDERS, VALVE
CABINET
Aerial 1, Aerial 2
2-Belling-Lee spade
SUNDRIES
t4
of 8-B.A.T., 1 -watt
type, consisting of two 500 -ohm,
two 5,000 -ohm, one 20,000-ohm,
SWITCH
EBONITE
1-Peto-Scott 13% in. by
s. d.
1-Packet
1-Set
RESISTANCES, FIXED
...
... 0
terminals,
... 0 0
marked: L.T.+, L.T.... 0 0
1-Belling-Lee banana plug
1-Set Belling-Lee eight -way bat-
4
2
... 0
...
15
LOUD -SPEAKER
1-Rota permanent-magnet moving -coil, type F5PM-PDT
...
12
... 0 16
... 0 16
... 0 17
6
6
6
VALVES
1-Osram S22
...
...
1-Mullard PM12A melallised
1-Osram PT2
...
...
tremendously marked.
Finally, make quite sure that your
set is really in gang. A set which is
not in gang will give you bad reaction overlap, bad quality, and it may
reduce the number of stations which
you can receive to about half. Ganging is perfectly easy if you follow the
suggested method.
31
T
Wireless Magazine,
August. 1933
the current all the time, not rectifying it as with A.C., but acting simply
as a conductor.
As yet, the British valve makers
have not come to any agreement over
the ratings of universal mains valves.
So far none have been produced in
this country, but we now have some
advance information of the Mullard
D.C. valves, and we understand
Cossor D.C. valves will be available
before the Radio Show.
These valves have 20- and 16 -volt
heaters respectively, so they can be
used in the same way as the Tungsram valves but there is the snag that
no rectifier has been produced.
Wireless Magazine,
' 's
!;.
'
'
,,,
"-:
August. 1933-1
,,
33
Wireless Magazine,
He
August. 1933
sat be
his bac
resting
grave,
expres
point.
Ir
the
proba
what
is a m
art. l
persoi
matte:
Ani
his se
me ui
in twi
turne
hope,
yet a'
WI
o;th
College
country
34
e
c
i
toc
Wa
of
to
he
ne
sh
hc
ai
si
rl
tl
c
y
Wireless Magazine,
He looked down at me where I
sat beside the students' work -table,
his back to one of the high windows,
August, 19331
35
Wireless Magazine,
August. 1933
Io
duction, I believe."
But this great little man, with his
smooth, pleasant face, lambent blue
eyes, and indomitable knack of
getting things carried out exactly
as he wants them, when these
things concern his work, would not
a-
..."
36
Wireless Magazine.
August. 1933 _I
mg
Ils,
en,
cal
lut
si-
so
1,
:r
ie
e
llowto Dcstju
A 1I1C.
CtI3ss..
71\
11111
37
Wireless Magazine.
August. 1933
touch.
This will normally include any
filament rheostat or switch and
the grid circuit, including its tuning
condenser. All of these have metal
parts which are liable to be touched
in the ordinary operation of the set.
Sets built on a metal chassis connected directly to a metal panel are
thus particularly dangerous, and
CC
D.G. MAIP15
it is.
Another Danger
If a second tuned stage coupled by
high -frequency transformer is used,
D.C.
MAIMS
danger.
Several precautions must therefore
be taken, both in the interests of the
set, the user, and the mains themselves.
Fortunately these precautions are all fairly simple, and
can easily be effected by any practical man, when the set can be made
perfectly safe.
First of all, the set should be
arranged with an automatic switch
which deadens all the interior when
the set is opened. This switch
should be of double -pole pattern to
ensure that the live main is broken
irrespective of any wall plug or
switching.
External operating switches should
be of insulated pattern so that no
live metal can be touched. Condenser spindles or any other control
spindles protruding through the
front of the set should be of minimum length and should have
insulated knobs of such size as to
make the spindles themselves inaccessible in operation.
Insulated Controls
METAL PANEL
Use of Condenser
Thus it is not permitted to earth
the neutral directly at the consumer's
wireless set, but since the " earthiness " that is required is only for
alternating currents, this is adequately provided by earthing the set
Wireless Magazine,
already stated, be directly earthed,
nor indeed must any part of the set
be earthed otherwise than via a
condenser as shown at c, in Fig. 2.
This diagram also shows the generic
arrangement of high-tension feed
and decoupling.
For reasons already given the
aerial should be completely isolated
from the rest of the set by the condenser c2i which should be of about
.1 microfarad capacity and should be
August, 1933
Wireless Magazine,
August. 1933
er the Counteal
In this short story J. GODCHAUX ABRAHAMS relates another
adventure
of Albert
" Portable
Goodger,
Wireless Expert
"
needed by a customer. His actual the pariahs of the radio world. But
stock is sadly depleted; in fact, if an according to his lights he is a wireless
inventory were deemed necessary all doctor and expert-and now you
that is needed is to count the few know him.
" Murder? " I inquired; I could
items of dust -covered wreckage
which he considers are attractive scent a story.
" Yes," he replied, as he gave a
features of his shop -window.
He is, by the way, a confirmed final twist to the last screw holding
pessimist. In his own words, Albert down the ebonite panel of one of his
Goodger is always " up against " sickly looking portables.
" Not but wot they could always
some knotty problem, and every set
which is brought in to him for guess that I 'adn't done nothing to
diagnosis and, possibly, subsequent their set," he continued, " but some
treatment, is always the worst he has of these folks are never satisfied.
Take, f'r instance, the case of the
ever handled.
For some reason-not far to seek, Elms. Why, that set of their's is a
in my opinion-his clients never regular come-back to me once a
entrust to his care any receivers of month regular. Sometimes hit's a
reputable make, but submit for valve wot's gone west; sometimes
repair, alteration, or completion hit's a knob wot's come off ; there's
weird contraptions built either to always something the matter with it.
" I'm sick of the very sight of it,
their own ideas or, if copied from
some blueprint, so far departing in but between you and me and the
form and character from the original gatepost, I wouldn't part with hit
"
that they would be unrecognised by for anything and
me so.
" But murder ? " I repeated.
Now and again, I have walked into their designers.
" Yes," he said, " that's hanother
Most of the instruments displayed
his shop in an attempt to buy some
(Although, figuratively,
oddment or other-not that I have on his work bench may be classed as story."
dropped aitches littered
often been successful;
the floor, he condescendin fact, as a rule, he
ed now and again to
has been " just out "
pick one up and use it in
of what I wanted. His
a word possessing no
stock of components
initial aspirate.)
reminds me of nothing
Fortunately, I was
less than a cemetery of
not pressed for time ;
shattered hopes.
the man interested me.
On his counter you
He was of a genus which
will see a motley colhad sprung up since the
lection of wireless re;f!
advent of broadcasting.
ceivers half - finished
I have since found that
which,
there are many Albert
started with a full
Goodgers in the wireless
meed of enthusiasm,
trade.
have been given up
He slammed down
in despair and, conthe lid of a portable
versely, finished reregardless of any ulceivers which, when put
terior effect upon the
to the final test, have
valves, and pushed it
sadly disappointed their
to one side. " It isn't
original constructors.
often," he began, " I
It is in this colsell a' nalmost noo wirelection of junk that
less set, but I got rid of
Albert Goodger delves
one for a friend of mine
when requested to pro"The old gal wasn't a bit surprised or taken aback like. 'My
at Easter. It was a fivea
component
duce
man,' she sez to me, ' hit's Playing all the wrong tunes "'
sets-sets
Wireless Magazine.
valver, you know ; one of those things
which they say can bring in anything
from
Mucklacker to Wheezing
[apparently Huizenl, not but wot the
old gal would 'ave understood anything of their outlandish lingo
when she got there but, it 'elps to
sez,
my programme, is supposed to be
doing a concert by the Wireless
Stories
August. 1933
of the Operas
'-I
41
Wireless Magazine.
August. 1933
(a)by
`
paraf
choke,
All
COMM(
possib'.
NOW TO GET
tory b
in wi
shows
90 cyc
EAL QUALITY
IN
Fig.
la.-A
Experimental Results
Nos. 1 and 2 fail in the treble,
No. 3 fails in the bass, while No. 4
fulfils all requirements provided a
small transformer is used with a
secondary winding of not more
than 6,000 ohms D.C. resistance.
Readers will, I hope, appreciate the
fact that in a short sentence I have
condensed the results of many
months of experimental work in this
connection.
The first low -frequency valve
should be of the type that is easily
loaded by signals impressed upon
its grid from a diode (with suitable
high -frequency amplification preceding it). A valve having an
amplification factor of 20 to 35 with
an impedance of between 8,000 to
12,000 ohms will be found to work
best in this position.
High -mu valves with an amplification factor of 70 to 80 are to be
avoided here until the manufacturers can produce one that amplifies
the higher frequencies uniformly
with the middle and lower.
Further Couplings
Now as to the next stage. Should
there be only one more stage ? That
depends on two things. First, the
Fig. Id. A coupling that fulfils all
average strength of rectified signals
requirements
impressed on the first low-frequency
valve and, secondly, the type of
Shall it be half- or full -wave recti- coupling used between the first
fication? The latter has its advan- low -frequency valve and the output
tages where sensitivity and automatic valve.
Assuming that the signal input is
volume control are required, but
from the point of view of high quality adequate and that the first low the half -wave rectifier is as good as frequency valve is well loaded, we
can easily load a super -power output
any other type.
How should the diode be coupled valve by using transformer coupling
to the first low -frequency valve ? between the first low -frequency and
One may have resistance, choke, output valve. Transformer coupling
or auto -transformer coupling. Four can be carried out in various ways :
2
Fig.
Ic.-A
42
be de
even
an in
henri
curvf
henr.
wou
secc
be
whi
To
sep
hig
im
qu
fre
an
th
is
st
rr
s
fi
v
c
Wireless Magazine,
(a) by transformer alone, (b) by
" parafeeding " with resistance or
Secondary Inductance
he
).
4
a
a
e
Fine Performance
What, then, is the best solution
for those who are unable to avail
themselves of the special de-luxe
Thus
Fig.
August. 1933
the complete
range from 23 to 8,000
cycles (at least) is
covered. Incidentally
it is possible to raise
the lower portion of the
curve for gramophone
amplification if required, and to control
the degree of curvature
very nicely, as I shall
show.
On coupler 3 we
depend for a good bass
register, rising below
90 cycles to 23 cycles,
43
valve.
No Errors in Wiring
The terminals of the transformer,
which may be of the AF3 type, are
marked in the diagram, so that there
should be no excuse for errors in
wiring. Any alteration in the connections here will spell certain failure.
A very wonderful tone control,
Wireless Magazine,
August. 1933
L34
e
ia
farad will be found to thereabouts. If this is done it is
G9
Cio
give the desired result. essential to use a separate choke
COIL
The condenser must and condenser circuit for each of the
R42
The combe of mica and capable valves thus paralleled.
000
of withstanding a high plete circuit diagram of the output
Rio
Re
An.r.r.Ann"
voltage peak, t h e stage is shown in Fig. 4.
working voltage being
G12
Common Output
v4b
equal to the maximum
EIEGTROSTATIG
Note that the common output is
employed for the last
MTstage.
taken from the middle point of the
Fig. 4.-Complete circuit diagram of the output stage,
In
the
grid
circuit
two filter condensers, c0 and c10f and
arranged to work into two loud -speakers
of the output valves we is connected to the primary of the
have a large auto -trans- matching transformer T4 (or direct
which enables the manipulator to former with a 2,000 -henry inductance to the speech coil if this happens
adapt the amplifier at this stage to winding. An AF5 will serve the pur- to be a high -resistance one) for the
the varying requirements of gramo- pose quite well.
purpose of transferring speech curphone reproduction and at the same
The tuned circuit of c, and this rents to a moving -coil reproducer;
time without upsetting radio repro- winding produces a resonance in while the same lead is also taken
duction, is shown in the diagram. the extreme bass. The shunting via another coupling condenser
This consists of a .02-microfarad condenser c8 must not be omitted. (c11) of .5 microfarad to the positive
condenser (c3) and a variable .25- The anode current passed through plate of an electrostatic loud -speaker,
megohm resistance in shunt across the potentiometer (n8) must not which is polarised in the special
the secondary winding of the auto - exceed 2 milliamperes. The chief manner shown in the diagram.
transformer.
value of the sliding control will be
With reference to the pick-up
seen when speech items are being connections for gramophone reBoosting the Bass
reproduced.
production, the circuit of Fig. 5 will
The grid -bias circuit for the last be found very satisfactory. PersonThe effect of this arrangement is
to boost the 50 to 100 cycle band, stage is not given, since the method ally I prefer a needle -armature type
while the high -note response is employed depends on the available of pick-up, with its minimum of
controlled by the variable
resonances, followed by a type
resistance (R4). If desired, a
J Novotone compensator.
Across the output of the
switch can be incorporated
latter is shunted a 500,000 for the purpose of removing
this control out of circuit.
ohm potentiometer for volume
The value of this special
control, while the variable
bass -boosting device is brillcondenser et is invaluable for
iantly demonstrated in the
controlling the intensity of the
reproduction of such a record
bass register. The capacity
as Bucalossi's "Grasshoppers'
of this condenser is decreased
Dance " (H.M.V. B39 70)
to reduce the bass, and vice
and also on Jessel's "Wedding
versa. A Formodensor type
TO Tl OF
COUPLER 1
of the Rose, " which is
H answers the purpose quite
FOR RADIO
recorded on the other side.
well.
for the use of a pick-up for reproducing
An even greater increase Fig. 5.-Arrangementgramophone
In conclusion, what are the
reccres
of bass is provided by
points of excellence which
substituting a .05-microfarad
this special amplifier is able
condenser for the .02-microfarad anode voltage. Automatic biasing to offer? The answer may be very
shown in the diagram, but the is not recommended unless the briefly given.
First, we have a
upper frequencies are not so well maximum anode voltage can be response curve that can be made
controlled in relation to the lower. maintained at 300 or more.
straight from 40 to 8,000 cycles, or
The small condenser shunted across
It is surely absurd to rob the all- modified at will to give a rising
the primary winding of the trans- important anode pressure supply characteristic.
former is optional.
for the sake of obtaining the correct
The actual response extends up as
The next stage is now given (see characteristic from the valve, when high as 10,000 cycles, as the elecFig. 3). Here we have in the anode far superior results can be secured trostatic loud -speaker will show.
circuit of the second low-frequency by using dry -battery bias or a second And the lowest frequency of 23
valve (which should be of the AC/P1 eliminator for the purpose. This, cycles is easily passed. The curve
class) a .25-megohm potentiometer, however, is a matter which must be is also peak-free.
with its centre terminal connected left to the good sense of the reader,
Secondly, there is sufficient control
to a coupling condenser for purposes who has hereby been duly warned
of tone and balance to satisfy the
of volume and tone control. The
We now come to the output stage most enthusiastic and fastidious
capacity of the condenser (c,) is by which the last valves are coupled connoisseur
HT+
'
w
4
f1
44
Wireless Magazine.
August, 1933
-and
of
Possible Cures
Here are a few notes on methods
of dealing with these types of
interference that have been found
to be successful from time to time.
They are not put down as universal
cures, but at any rate they are all
worth trying.
In this connection it may be said
for a start that A.C. induction and
synchronous motors, which have no
brushes, are much less liable as a
rule to cause trouble than D.C. or
A.C. commutator motors.
Practically all the electrostatic
(audio -frequency) and the radiofrequency interference come from
sparking brushes :
Magnetic (audio frequency).Complete screening of the motor in an
iron box below the motorboard is
the only sure cure; and the iron has
Oiling
to be fairly thick, say, } in. or more. since it may be dangerous for the
Sometimes, however, facing the inexperienced, the same rules apply
underside of the motorboard with both to spring motors and to
iron -sheet is sufficient.
electric motors. There is, however,
These are somewhat trouble- just this difference : an electric
some methods and before embark- motor runs warm and therefore
ing on them it is always well to try demands more frequent attention.
the effect of a different orientation
The parts to look to are the
of the motor in relation to the pick- following
up; that is, try turning the motor
(1) Spindle bearings : a single
frame round, the spindle being ball bearing, as a rule, at the foot of
kept in the same position; or, the spindle and a sleeve bearing at
alternatively, try mounting the the top where it goes through the
pick-up arm at different places at motor frame. Use light oil (say,
the same distance from the turn- Wakefield's Oilit) rather sparingly
table spindle.
(three or four drops a month).
The frame of the motor and the
(2) Drum bearings in spring
pick-up head and carrying arm motors : light oil-three or four
should always be " earthed." drops.
Sometimes " earthing" one or
(3) Armature bearings in electric
other of the two through a con- motors : light oil-one or two drops.
denser and the other directly
(4) Governor spindle bearings :
improves matters, but these occa- light oil-one or two drops.
sions are rare.
(5) Governor Worm : On no
Electrostatic (audio-frequency). account use liquid lubricant; it has
Here, again, complete metallic the knack of penetrating and
screening, with the screen and the distorting the fibre worm wheel.
pick-up head and carrying arm Non -gritty motor grease is best.
earthed, is the surest method. In
Free from Grit
the case of commutator motors,
however, the connection of a
(6) Governor brake pad. This is
2-microfarad condenser between the part most often ill-treated, yet
the frame and one of the brushes it is perhaps the most important.
often works wonders; which of the The pad and disc on which it
two brushes to connect to has to be operates should be kept scrupulousfound by trial.
ly free from grit.
In one instance (an expensive,
The pad should be soft and
yet deservedly popular motor) uniform, not shaggy, and should
wrapping the spindle with stamp occasionally be lubricated with light
paper, so as to insulate the turntable oil. Try to squeeze out any old
from it, was equally successful
oil before putting on the new and
Radio frequency. The methods clean the disc with soft rag.
described for electrostatic are apThe so-called " squaring " of
plicable, but not always successful. the governors is almost invariably
The best counsel of all is that due to a poor or dry governor pad.
you should choose a motor which In this case, the governor takes up
gives none of these troubles. Nowa- a set pattern and operates in noisy
jerks.
days there are many good ones.
:-
45
Wireless Magazine.
August. 1933
T
Wireless Magazine.
August, 1933
Fig.
by a
47
Wireless Magazine.
August. 1933
the current has a much smaller
value. Sometimes the current is
actually in advance of the voltage,
and sometimes it lags behind it.
Clearly, then, the peak values or
maximum values and the zero values
do not occur at the same instant,
and this is referred to as phase
displacement.
Out of Phase
Fig. 3 is an oscillogram which I
have specially arranged to illustrate
two waves which are out of phase.
Fig. s.-Oscillogram of current after full -wave rectification, as employed
Three Secondaries
This transformer has three
The first
secondary windings.
winding supplies current for the
heaters of the valves, the second
heats the filament of the rectifying
valve, and the third winding provides
the necessary high voltage for the
rectifier valve, from which we obtain
our finally smoothed or direct -current
output.
The voltage as supplied by these
three secondary windings has
exactly the same wave form as that
in Fig. 1 or Fig. 2.
You will notice that I have
mentioned both current and voltage.
Fig.
7.-Another example of a poorly smoothed mains supply, which will also cause hum.
This is from a full wave rectifier
Wireless Magazine,
August. 1933
After Rectification
Fig. 4 is an oscillogram of the
current after it has been rectified by
the valve. Here we see that we
have actually cut off all the peaks
on one side of our datum line.
This is known as half-wave rectifi-
Fig. 9.-Oscillations as received in the aerial circuit of a radio receiver. Note the
similarity to the low frequency wave forms
Tuning Receiver
Wireless Magazine,
August. 1933
spssrh or music. (This photograph was not taken with a cathode-ray tube, but by
another method explained in the article)
50
Ad,
mean
used
Adag
passa
Al
used
mov
thou
whit
ever
mea
quit
Hal
hov
spe
ho'
the
sot
re:
wl
hi:
ne
te
ci
o'.
it
0
I
Wireless Magazine.
August. 1933
voice.
find
information on musical
instruments, both singly and as
used in well-known groups
Celeste or Celesta-mustel
Wireless Magazine,
August. 1933
w!sea in
ponsored Programmes
Our special commissioner describes the latest
arrangements for broadcasting sponsored programmes from the Athlone station-the only
English-speaking station on this side of the Atlantic
giving programmes sponsored by advertisers
...
52
is misplaced in broadcasting,
and
all costs.
programmes
has
arranged
sixty-seven
high-class
concerts through Athlone. A group
of prominent British advertising
agents have prepared a report which
is favourable to sponsoring, and so
it is unlikely that there will be
shortage of material.
In brief, the men behind the
Athlone publicity scheme have had
experience
of broadcasting
in
Europe and Australia; and they are
out to give the best radio entertainment through Athlone-to make it as
widely known in the British Isles as
are the French stations through
which we already get sponsored
programmes.
Athlone's wavelength of 413 metres
has the advantage that it does not
Wireless Magazine,
necessitate switching to the long
waves.
It would be a big setback to the
sponsored programmes if there were
British Built
The Athlone transmitter is
British built by the Marconi
organisation. With its power of
60 kilowatts it is a strong signal in
this country. It is crystal -controlled
to ensure a constant wavelength, is
modulated up to 80 per cent. and
has a 300 -ft. high T -type aerial.
In general appearance the Athlone
broadcaster is exactly like one side
of a B.B.C. transmitter. There are
the six familiar units
aluminium
panels and glass fronts. There is a
control desk fitted with relays and
indicator lights.
It can work on any wavelength
between 300 and 550 metres, so that
there is plenty of room for modification under the new Lucerne
scheme. It works on 413 metres as
this was the wavelength formerly
used by the Dublin broadcasting
station.
The sponsored programmes, of
course, will be given in the English
language, but announcements will
undoubtedly be made from Athlone
in Gaelic. It is conceivable, therefore, that the sponsored programmes
will be a " bright spot " in the
evening broadcasts from Athlone and
will please Free State listeners as
much as the British listeners for
whom a large proportion of the
sponsored programmes will be
intended.
are often
puzzled to know why a particular set has a somewhat restricted
wavelength range; in extreme cases,
for instance, it may not go down
below 230 metres, and a large number
of stations below that wavelength
cannot be heard.
It is interesting, therefore, to
glance at some wavelength and
capacity figures supplied by Wilkins
and Wright, Ltd., for their types
W313 and W314 Utility gang condensers. These figures show how
important it is to choose a coil of the
right inductance; and how it is
equally important to keep down the
stray capacities in the circuit if a
good wavelength range is to be
covered.
With a medium-wave coil of 146
microhenries inductance, for instance, and a stray capacity of 30
micromicrofarads the condensers
referred to give a wavelength range
of 176 to 532 metres, that is a total
spread of 356 metres. 'With a stray
capacity of 40 micromicrofarads the
range is from 191 to 537, a spread of
only 346 metres ; while with 60
micromicrofarads the range is 216
to 547 metres, the spread being
reduced to 331 metres.
With a coil of 158 microhenries
inductance a capacity of 30 micromicrofarads gives a range of from
183 to 552 metres, a spread of 369
metres; 40 micromicrofarads gives
197 to 558 metres, a spread of 361;
and 60 micromicrofarads gives 225
to 566 metres, a spread of only 341
metres.
If the inductance of the coil is
The Wireless
Separate Company
Incidentally, the Athlone publicity
is
an
entirely
organisation
separate company having the whole
rights for the Athlone publicity
broadcasts and having no connection
with the publicity concern which
has run sponsored programmes
through Paris, Normandie and elsewhere.
August, 1933
LESLIE M. OYLER
53
Wireless Magazine,
August. 1933
9e SF[F{ONTAINED
FOUR
with Iron -core Coil
er Class -B Output
54
ceiver, we
great deal i
a second
these page.
Being
it is usefi
from one
all kinds
some mi
to listen
on the p
out," as
into an
different
happy.
The
though
parts
the unc
basebo
difficu''
As
cost of
this
heavy
can u
the sr
exper
lying
be a
for a
consi
mate
built
all
prit
58.
I
dial
be
sta
the
du
Li
a
ti
Wireless Magazine.
ceiver, we do suggest that there is a
great deal of fun to be obtained from
a second set of the sort shown in
these pages.
Of Great Utility
Being completely self-contained,
August. 1933
.1
55
Wireless Magazine.
August. 1933
boas
Economical Running
The total anode current when
batteries.
A word about the controls. I
found the set extremely simple to
handle. Except for the very weak
foreign stations there was no need
to use the reaction control-the
knob on the extreme right of the
panel. On London Regional the
best results were obtained with the
reaction control at zero and the
variable -mu potentiometer in
about the half -way position.
The frame aerial has very
marked directional properties, and
it was essential when receiving
foreign stations to turn the set
about until the best results were
obtained.
Increasing Selectivity
To get the best selectivity
when tuning in foreign stations,
mit
ri
ten
m
(wi
bat
hol
the
de
te
sp
ri]
in
ir.
ir
Z
b
c
c
Wireless Magazine.
board to the driver transformer and the two .002microarad condensers.
Three special points should be noted
(1) The loud -speaker transformer has three
terminals, two being connected to the anode terminals on the class -B valve holder and the third
(wire No. 67 on the layout) to the high-tension
battery. Connections Nos. 55 and 56, from the valve
holder, should be made with metal -covered flex,
the metal braiding being earthed.
M1.13.31
:-
4g
41006
`ON"'v
` ..n.
m.o.u,
ncuLobnu:$x5P4.
Y
5wnu
165.0
August. 1933
23rD
COM,_Wee
omE
6
65
r
om
fi
14%
Ev1lllllllllllll`
'
3''..1''''.-..":"i."..:-7.
.
6
kt
qTL` OV[6YL 6aL Or ,Mn[ Maanb Inns..M
r6 xlbb Y
dk
efficient.
that there are two high-tension tappings and two grid -bias
tappings (there is no bias on the class -B valve).
For the sake of convenience high-tension batteries
tapped at every 1.5 volts for the first 9 volts are used ;
in this way a separate grid-bias battery can be dispensed
with. The connections should therefore be made as
:-
follows
Place the G.B.-2 plug in the negative socket of the
first 60-volt battery; place the G.B.-1 plug in the
6 -volt socket; and the G.B.-1- plug in the 9 -volt socket.
Then connect the 60 -volt socket of the first battery to
the negative socket of the second battery. H.T. +1 is
57
Wireless Magazine.
August, 1933
0
0
s.
4
3
d.
0
12
(3
6
6
...
...
10
L.T.-
BATTERIES
2-Pertrix 60 -volt high-tension,
ultra-capacity type, model 237
CABINET
1-Cameo Carrier portable
LOUD -SPEAKER
0 16
... 1 15 0
0
0
ACCESSORIES
1-Exide 2-volt accumulator, type
1-0O3 (or Lissen, C.A.V.) ...
(or Clix,
0 10}
l0i
SWITCH
G.B.
50,000-
say...
-2, and 2
s.
SUNDRIES
CONDENSERS, VARIABLE
marked H.T.+2,
H.T.-, G.B.+, G.B.-1,
... 0
RESISTANCE, VARIABLE,
COMBINED WITH SWITCH
1-British Radiophone
VALVES
... 0 16 6
... 0 7 0
... 0 7
... 0 14 0
0 10i
The prices mentioned are those for the parts used in the original set; the prices of altern:dives
as indicated in the brackets may be either higher or lo;er
fi
11
conditions.
If the set is taken out in a car
outstanding results must not be
expected whilst the vehicle is in
motion. Unless a passenger is going
to sit by the set and turn it round so
that the frame aerial is always pointing in the right direction irrespective
of the curves of the road pronounced
fading must be expected.
Another trouble to be expected is
interference from the ignition system
on the car. This can be overcome,
however, by the simple expedient set
out in the article, " Motor -car
Radio," that appeared on page 574 of
the July issue of " Wireless Magazine."
Value of Turntable
Whether the set is to be used
indoors or out of doors, it will be found convenient
to screw a small turntable to the bottom of the
cabinet. Such a turntable can be obtained from most
radio dealers for a few shillings and will prove a real
boon. By swinging the set the selectivity can be
controlled within very fine limits.
When you have had the set in use for a reasonable
time, don't forget to let us know what results you
get-all such reports are very helpful.
then tapped at
about 9 volts on
the second battery and the
H.T.+2 plug is
placed in the
60 -volt socket.
The controls
of the set are
quite straightand
forward
can be mastered
in a few minutes.
The two controls on the left
are for frame tuning
aerial
three-point
nev
the mar
first set
Probabl;
why thi'.
they wt
what hs
Mayl
experte
inform
relatini
winter
cannot
Just
take a
say,
the f
evenil
a " S
night
of th
coup
ment
in
Sc
n
gene
that
"thi
rect
tim
W1I
wo
lig
da
th
(top) and
volume control.
With the latter
is incorporated
Tie
v
u
A HANDSOME SET
Housed in its Cameo cabinet, the Self-contained
Four looks all that a good portable should be
Wireless Magazine,
HIS article
Weak Foreigners
The locals seem to come in quite
well and no difference can usually
be detected, but all those foreigners
upon whom we used to rely for
variety when the local stations bored
us are either unobtainable or so weak
as to be scarcely worth listening to.
And then, in the last week or two,
the local has been varying strangely,
sometimes in jerks, going right off
for several minutes; at other times
giving long, very weak periods,
alternated with bursts of strength.
If it is a home -built set the user
quite likely thinks his valves are
wrong, that his battery wants charg-
August, 1933
that their direct waves are insufficiently powerful to reach us, and we
have to rely upon the indirect ray
or reflected wave, which is only
available after dark.
And that is why you notice such
a difference now that much of your
reception is done in daylight. Up
till quite recently all your listening
has been done after dark and you
were getting both direct and reflected
waves, and altogether quite a good
collection of programmes.
Now until darkness settles over us
you are getting only the direct waves
and your programmes are thereby
reduced in number. Do not blame
the set; it is a natural condition and
is nothing whatever to do with your
valves and batteries falling off.
When it is really dark the set will
work quite well.
Even the reception of the reflected
waves is generally poorer in summer
than in winter and the atmosphere
does not seem entirely to lose the
daylight opacity to these waves after
dark. Experienced listeners never
expect summer conditions to be as
good as winter and are, therefore, prepared for the changes which occur.
is
Wireless Magazine.
August. 1933
Cossor Cathode-ray
Tube
The Newlelevsion
by Cathode raylube
by MORTON BARR
Amazingly Clear
One remembers how amazingly
clear and distinct
the early broadcast
programmes were,
even on a simple
crystal set. The
B.B.C. came in
with a bang-one
might say,without
much advertisement-and almost
fully fledged from the start.
Ten years have naturally brought
some progress in their train, for
SIMPLE TUBE
instance, the super-het and other A cathode-ray
tube for
highly selective types of receiver, but perimenters developed
Manfred
von
Ardenne
the essentials of transmission and
Germany
60
ex-
by
in
Limited Subscribers
A wired relay service is not, of
course, an ideal solution for the
ordinary householder, but it is quite
Correct Alinement
The essential difference between
television and broadcasting lies in
the fact that " picture " signals have
not only to be received in a time
sequence, but must also be distributed in correct alinement, that is,
in proper space sequence on a viewing screen.
In broadcasting syllables and
words follow each other automatically from
the
loud -speaker. But
suppose one had
to spell each message out, letter
by letter, say, by
focusing a lamp,
from square to
square, on a screen
containing t h e
Wireless Magazine.
alphabet arranged in the usual order
from A to Z.
That would be a very different
matter, and broadcasting under such
conditions would probably still be
" in the doldrums," struggling along
with television, because it is just
such a problem that the latter has to
August. 1933
CONTROL GRID
ANODE
solve.
tP
FLORESCENT
SCREEN
/I
61
GR1'
Wireless Magazine,
August, 1933
Condenser
Confusion
HE average reader is very
THE
a condenser of
when
the non -inductive type is specially
mentioned for use in the high frequency side of any particular
circuit. The general idea is that a
condenser of a certain capacity
should be suitable for any circuit
providing the test voltage is high
enough.
Non-inductive Types
Operas and
Oratorio
WHAT should be done with opera
and oratorio ? Many listeners
like both. The length of either type of
work often spoils it for broadcasting.
The same thing applies to plays by
Shakespeare. In this case judicious
cutting has brought them down to
Wireless Magazine,
Cetti
By J.H.REYNER,
THE classB
August, 1933
valves
on the
market will all
give an output
of 1i to 2 watts
under suitable
now
conditions.
Some people
to 2jr
13
output required
in order to reproduce the peaks
without distortion would be
twenty or twenty-five times as
great, requiring
an output of 2
watts. In some
Modulation Percentage
Confirmation of these figures is
afforded by the modulation percentages of various transmitting stations.
In this country the average modulation depth is about 20 per cent, rising
on peaks to slightly over 80 per cent. ;
a change of 4 : 1 which involves a
power change of 16 : 1.
It is well known that the B.B.C.
engineers deliberately compress the
modulation, possibly in order to give
more pleasing reproduction on small
power sets which are incapable of
" stretching their shoulders " sufficiently.
Continental Practice
Many Continental transmissions,
on the other hand, do not adopt this
policy, in which case the average
depth of modulation is about 12 or
15 per cent., rising again to 80 per
cent. or even more, which gives a
change of over 6: 1.
The fact is that the output salve
requires elbow room. If it is allowed
freedom of movement the quality
sounds full and rich without by any
means being overpoweringly loud.
No one suggests that the average
power output should approach 2
watts. It is only on peak signals that
it is required.
On the other hand the small
power valve, such as we have been
Wireless Magazine,
August, 1933
Radol ym pa
-dated September-will
all over the
August 15.
sale
be on
country on
sets
overload a small-
'
Special Batteries
The figure is well within the
capabilities of the double -capacity
size, which indeed will do for five or even six-valve sets, while for
simple three-valve sets most of the
battery manufacturers are producing
special class -B batteries capable of
an economical discharge at about
10 milliamperes. Any doubt on the
score of battery life is thus
dispelled.
To sum up, your class -B valve
will give you depth of tone with full
volume when you want it, but its
average level need not-in fact,
should not-be much above that from
a normal power valve.
Effective Consumption
Under these conditions you may
The effective consumption is succession.
expect long life and good service
checked by using a device called a
The standing anode current with no from both valve and batteries.
silver voltameter. This consists of signal was 5i
two silver electrodes in a solution of milliamperes
silver nitrate and if current is passed for the driver
through it from one electrode to the and output
other the liquid is decomposed and valve combinsolid silver is deposited on one of the ed, and the
plates.
average curThe amount of silver deposited is rent for the
proportional to the current and, sametwovalves
therefore, by weighing the electrodes over the whole
before and after the experiment the programme
total quantity of current which has was 8.9 milliflowed can be estimated and this, amperes, an
divided by the time, gives the average increase of only
current in milliamperes.
62 per cent.
64
1
ter
br
tui
wi
da
cc
th
fa
ti
n
n
e
Wireless Magazine.
August, 1933
yitn NOTES
S
amtNEWS,
By T. F. Henn
Wireless Magazine,
August, 1933
Those readers who are interested
in his music should make a note that
H.M.V. have issued a special album
of six records consisting of tunes by
which Ellington has made his name.
None of the records have been
issued in this country before.
While on the subject of broadcast
1
are one of the few bands that keep
really good time. Although only a
small band, they have the happy
knack of varying their programmes.
Corelli
66
Wireless Magazine,
Alcock, the B.B.C.'s organ consul-
tant.
::
"
studio
"
broad-
August. 1933
Unique Harmonies
Martha,
developed
when they
and soon
All ready for a Cockney impersonationViolet Lorraine. She had a great success
in " Business As Usual"
67
Wireless Magazine.
August, 1933
opini
for
impr
My
ur
TeSt42I
strer
free
but
perf
usu<
fron
0INSON
tmtaCao.fo
dur
dur
FINE JOB
The construction of
the All -metal Four
was fully described
Th
an(
anc
bOL
tre
or
re
in
a
1
last month
I1
IRON-CORED
tuning coils I have
experimented with,
Good Quality
With regard to quality, I can only
say that I first noticed some very
good drums, without any overstressing of the bass, and then became
aware that all the higher frequencies
were there as well in something like
proper proportion.
Naturally enough, when you are
getting really good quality, such as
will appeal to the musician, you
cannot have so-called " knife-edge
selectivity." The two things do not
go together, even when iron -cored
COMPLETELY ASSEMBLED
Here is the All -metal Four completely housed in
its Camco cabinet. It is not difficult to build
Station
Eiffel Tower
Motala
Moscow WZSPS
Luxembourg
Daventry
Oslo (not identified)
Medium Waves (Full strength and uninterfered with)
Station
Degrees
Station
Munich
170
*London Regional
Vienna
156
Brussels No. 2.
*Brussels No. 1.
148
Milan
*North Regional
134
*Post Parisien
*Langeiberg
130
*West Regional
Beromuenster
121
North National
Rome
117
Scottish National
Stockholm
114
Heilsberg
Athlone
104
Bari
Katowitz
100
*London National
*Midland Regional
97
*Trieste
Toulouse
91
*Bordeaux
Scottish Regional
85
*Fcamp
*Received in daylight at good or full strength
Degrees
165
160
150
140
128
117
Degrees
104
83
75
60
30
Degrees
75
64
62
60
49
45
40
38
31
25
17
12
68
Wireless Magazine.
opinion 50 ft. of wire is quite enough
for this set and would greatly
improve the selectivity.
I had twenty-five stations at full
strength on the medium band quite
free from interference, and ten faint
but fairly good. On the long waves
performance is excellent, and all the
usual stations were received free
from one another.
Conditions were extremely difficult
during my tests, which took place
during the weekend of June 17-18.
Thunder storms were chasing one
another all round me for three days,
and the crashes and bangs in the
loud -speaker were more than distressing.
Roar of Statics
There was not a quiet period day
or night, and for hours on end the
s. d.
2
0
0
1 11
620
...
..
... 0 2 0
2-Dubilier .0002-microfarad, type
670
0 2
0
1-Dubilier .001-microfarad, type
820
0 2
0
1-Dubilier .01-microfarad, type
620
...
...
...
... 0 3 '0
1-Dubilier .2-microfarad centre tapped, type BE31L
... 0 s 0
2-Dubilier .25-microfarad, type
BB
4
1-Dubilier .5-microfarad, type BB 00 2 66
2-Dubilier 1-microfarad, type BB 0 5 0
4-Dubilier 2-microfarad, type BB 0 14 0
2-Dubilier 8-microfarad, electro-
CONDENSERS, VARIABLE
11
3-British
METAL CHASSIS
1-Magnum special metal chassis,
RESISTANCES, FIXED
1-Packet of 15 Erie 1 -watt type,
s.
consisting of 1- 850;
4- 500;
RESISTANCES, VARIABLE
1-Preh
August, 1933
0
0
6
SUNDRIES
SWITCH
2
0
0
1-R.I.
TRANSFORMER, MAINS
1-Wearite, type T21A ...
... 0
... 1
1 15
ACCESSORIES
CABINET
1-Camco Empire table model, in
2-Marconi
or
Osram
VMS4,
Catkin type
..
... 118 0
1-Marconi or Osram MS4B, Catkin
type
...
...
...
... 0 19 0
1-Marconi or Osram MPT4, Catkin
type
...
...
... 1
0 12
0
6
Control of Volume
THIS de-
pends very
largely upon the
type of set. What
we must do is to
avoid overloading.
In
simple
receiver we can
certainly control
the volume by
a
three-valve
connecting
suitable device to
the output of a
detector circuit,
but the result of adding this may well
be that on the local stations the detector valve would be grossly overloaded. In a set of this sort, therefore, we must put the control before
the detector.
If, now, we connect it to the input
of the detector, using, for example,
a potentiometer across the intervalve
coupling, we shall certainly avoid
member of the" W.M." staff trying out the All -metal Four,
which has two screen -grid stages
69
Wireless Magazine.
August, 1933
m
o!
NEWS
SFTWAVS
By KENNETH JOWERS
able constructor.
It is for this reason that, as
and when space permits, we
shall in these notes include
information about short-wave
transmitting gear.
bands.
Not Trustworthy
In my set, for example, when I
change this valve it alters the tuning
reading by 5 degrees at 15 metres I
Obviously, this sort of calibration is
not trustworthy, because it is below
20 metres that real accuracy is so
essential.
An absorption wavemeter is the
simplest type of wavelength check
you can have. It consists of a coil
tuned by a condenser, with a large
tuning scale calibrated inwavelengths.
All you do is to hold the coil reasonably close to the tuning coil of the
receiver and then, by tuning the
condenser of the meter, you can hear
a distinct click when you reach the
resonant point.
Here, again, below 20 metres the
70
Improved Signals
During the past two or three
months his signal strength has improved very much, although when he
re -appeared a month or so ago his
speech was much weaker than his
music.
>>
r
a
Wireless Magazine,
mainly through the over -modulation from Texas, at R4, and he uses only
of the French stations.
90 watts on 20 metres.
.
I used to hear quite regularly
The Marconiphone Co., Ltd., has WICAA, from Lynn, Mass. He
just lent me a new valve that will be came over R6 to R8 for the first
on the market very shortly. It is desig- three months of this year, but lately
nated DET5-what a valve ! It has there has not been a trace of him.
a special bombarded grid, making it Now comes a letter from him
very suitable for 56 -megacycle work explaining that, as he is a U.S. naval
really good valve at last for reserve officer, he had to go to sea
5 -metre fans.
for training, but he will be on the air
again as from July 27, and hopes
Output of 32 Watts
to renew contacts with friends in
Although rated to give 25 watts at Europe.
400 volts on the anode, I have had
32 watts without any difficulty.
With the Short-wave Listener
What is more important to the
Apart from picking up amateur
amateur with a lean purse, it costs
only 1 15s. At 400 volts on the stations and " locals " such as Rome,
the short-wave listener is not having
anode it passes 62.5 milliamperes.
I have just obtained a lot of a lot of luck just now.
These lovely summer days are
interesting dope from Cossors' about
using small valves as oscillators and calling me out quite frequently, so I
modulators. I cannot possibly give am not able to keep a very regular
all the details here, but if anyone schedule. I do find, though, that con
would like to know more I will send ditions above 20 metres are not at all
reliable for D.X. work.
them a copy.
The static on 50 metres is bad up
For those using batteries and
accumulators for the power supply of to at least 1 a.m., while on the
the transmitter, I have an excellent 31 -metre band reception conditions
circuit of a class -B valve used as a are definitely poor. I have heard a
modulator, which is giving fine 25 -metre relay from W8XK quite frequently and when I have gone after
results.
W2XAD I have always heard him.
My biggest trouble at the moment
Portable Transmitter
is GSG, the Empire station on
I had a letter the other day from 16.86 metres. He comes through
W9BHT, who, as you all know, extremely well in the afternoon just
hails from Illinois, telling me of the when I want to listen to W3XAL on
closing down of his station for three 16.87 metres, and I find that the
months as from July 1. In the mean- 10 -kilocycle separation is barely
time he will be operating W9DXJ, a sufficient.
There seems to be no end to the
portable outfit, using up to 200 watts.
His power supply will he derived phone stations between 14 and
from an A.C. " genny " driven by a 16 metres. There are at least three
small gasoline motor
He is fifty from Buenos Aires, and two from
Rio, all of which come over at amazmiles from the nearest power main.
You may think he is a great opti- ing strength, irrespective of prevailmist trying to work Europe on this ing conditions. I have also heard
gear, but I have heard W5AE, also some of the test transmissions from
Tokio on about 15 metres, but the
strength was only about R3 at the
most. I notice that W1XAL has
been coming through very nicely on
the 48-metre band, even better than
Pittsburgh. I have also heard him
on about 22 metres, but not reliably.
The Empire transmissions are
proving very satisfactory and their
success is leading other countries to
emulate the B.B.C., so that now
Germany has half a dozen Zeesen
relays, France three or four Paris
relays, and even Belgium, which
Fig. 2. How to use a class -B valve as a
sends out short-wave stuff to the
modulator in order to get a high output
Belgian Congo, has an " Empire "
from a low -voltage supply
station.
-a
71
August, 1933
Wireless Magazine.
August. 1933
was written for a boy and somehow neither fits a boy's voice.
While I do not wish to suggest
that the singing is bad on either
side, I simply do not feel I can
recommend either of these works
unless sung by a woman. Tradition is too strong, I fear.
CLASSICAL
ORCHESTRAL MUSIC
*Brandenburg Concerto No. 5
*Preciosa
Overture (Weber)
Berlin State Opera
Orch., 4s.
(d.s.),
it!
CHAMBER MUSIC
*(a) Air from Suite in D
Transcription
(Bach),
(b)
Quartet No. 1 in D Major
Finale Allegro (Dittersdorf),
Lener String Quartet, 25. 6d.
COL DB 1133
Of the two, I prefer the Bach,
because of the oualfty of the tone.
The Dittersdorf is "well together"
-one would hardly expect anything else of the Lener people
but the tone is a little too brilliant.
However, turn them down a trifle
and I think you will find a good
rendering of a beautiful work. A
fine record, really.
LIGHT ORCHESTRAL
Irish Medley, (b) Welsh
Medley, Debroy Somers Band,
2s. 6d.
COL DB1130
A characteristic production of
this well-known band. It contains
many melodies you know and the
whole record can be danced to as
a one-step.
The production is
good throughout.
(a)
SACRED MUSIC
you are-buy
H.M.V. DB1876
WILSON
(a)
By WHITAKER-
LIGHT SONGS
beautifully orchestrated.
the
mosque scene attracts me very
much. I think, after hearing them,
you will agree with me that you
get your value for your money, so
to speak, in the opportunity you
have of hearing various orchestral
instruments playing solo.
Lehar Melodies (d.s.), Ilja Livschakaff's Orch., as.
DECCA F3575
Reminiscent of most cinemas.
You feel there ought to be a picture supplied with the music,
which is quite attractive, but
rather sugary. This is not intended
to be a negative review at all; it is
that sort of music !
(a) In Old Vienna, (b) Old Spin-
(a) Danny
2s. 6d.
H.M.V. B4453
Quite entertaining and rather
cute. He does one bit one day,
presumably, and then the other
part the next.
Not always
together with himself. That comes
It is practically
in fox-trot rhythm, with nothing
very wonderful to relate about the
tunes in it.
is not too good.
4s.
COL DX472
Henry Hall playing : Merry
Widow waltz, Gypsy Love waltz,
and plenty of others you will like.
You can safely invest in this, I
assure you.
PIANO SOLO
(a) Aragonesa,(b) Tango, William
Murdoch, 2s. DECCA F3584
Do not think the tango is a
dance piece, or you will be disappointed.
It is evidently an
arrangement by Godovoski.
I
think the disc is worth getting for
the Aragonesa, which is a delightful work of a light character.
Murdoch's playing on both sides
is first rate. The Aragonesa is
going on while I write. Yes, you
will like it; it is a very attractive
piece of writing.
SONGS
(a)
Friends
DECCA M438
The gypsy song appeals to me
-rather well written. I do not
remember having heard this singer
before, but I hope to do so again.
His tone and phrasing are good
and he takes the trouble to pronounce his words. I should like
Decca to get him to record some
better songs. He is rather a find
*(a) Mazurka in
C Sharp Minor
(Chopin),(b) Nocturne In E Flat
Major (Chopin), Ignace Jars
Paderewski,6s. H.M.V. DB1763
This ought not to be missed.
"Paddy's" renderings of Chopin
have an authority behind them
which cannot be gainsaid, much
less ignored. Blood is thicker
than water and he is a Pole, just as
Chopin was. Very beautiful it all is.
*(a) Partita No. I in B Flat
Major (Bach), (b) Romance In
F Sharp Major, Op. 28, No. 2
(A
(Schumann),
Song
John
Hunt,
2s. 6d.
H.M.V. B4438
The Bach is very attractive -1
mean to every reasonably intelligent listener-because it is simple
in construction. The Romance is
well known, of course. Both are
litan Love
(T'Amo),
72
By
CHOPSTICK
DANCE MUSIC
*(a) Decca Stomp (f.),
(b)
easily guessed.
My Love
*(a)
Of (f.),
Wireless Magazine,
August, 1933
klestriefor
By the
bit Buy
"W.M."
FREE ADVICE
TO PROSPECTIVE
SET BUYERS
:-
73
Wireless Magazine,
August, 1933
POWER SUPPLY
A.C. mains.
:
Oliver Pell Control
(Varley), Ltd.
PRICE : LIS 15s.
VALVE COMBINATION : Super -het
sequence. with AC/Pen output
and DW3 mains volve rectifier.
POWER SUPPLY: A.C. mains.
MAKERS
REMARKS
Quite apart
from the selectivity the range is
phenomenal, and
it is just for these
summer days and
long, light evenings that
the
reserve of power
of this type of
and
:
Quality above the
average, and plenty of stations
without interference.
REMARKS
instrument
so useful.
TYPE
is
We
were able to get
more than half a
dozen foreigners
full
on the medium
waves, even with
an indoor aerial.
After dark the
usual twenty-five
to thirty good
programmes were
available without
forcing the
volume control to
the limit. The mains aerial picks up many of these
-stations quite well, though some form of external
aerial was found preferable for reducing the background.
When the lid is shut down the volume control on the
front can still be worked on radio or gramophone records.
With the lid open you find the controls on a neat panel
on the right, knobs being for tuning, switching, and tone
control-that is, high-note cutting.
On the left is the familiar automatic -record -changing
mechanism, which is now notable for a number of
detailed refinements.
Needle -scratch can be cut out entirely by adjusting
the tone control, which also has the effect of cutting
down crackles when on the radio side.
Mains hum is negligible, and even without the earth
cannot be heard a few feet from the loud -speaker. The
earth improves the strength, but a large aerial is quite
unnecessary; in fact, 10 ft. of wire proved ample to
bring in all that was going.
The tuning scale is wonderfully easy to read, the
calibrations rotating with the wave -change switch knob,
so that only the wanted wavelengths are in view at any
given setting of this knob.
74
super -het
Wireless Magazine.
I4
14s.
VALVE
August, 1933
SUPPLY: Self-contained
batteries.
POWER
MAKERS
PRICE :
A. C. Cossor, Ltd.
t9 I9s.
VALVE
milliamperes.
TYPE : Portable set with movingcoil loud -speaker.
Needs no
extras.
REMARKS : Very fine volume with
good quality.
POWER
SUPPLY :
batteries.
Self-contained
Regional
The makers provide a very comprehensive chart
giving calibrations for many foreigners.
75
rWireless Magazine,
August, 1933]
Smurthwaite Radiogram
MAKERS : F. W. Smurthwaite, Ltd.
PRICE : L22 Is.
VALVE COMBINATION
Variable mu
high -frequency
(Mazda
S215VM), detector (Mazda HL2),
driver valve (Mazda L2), and
class -B power output (Mullord
PM2B).
POWER SUPPLY : Self-contained
batteries, with 120 -volt high:
tension.
detector
(Tungsram
Barium
P0220)
and
power
output
(Tungsram LP220).
POWER SUPPLY : Self-contained
Exide high- and low-tension
batteries.
from
battery instrument.
milli-
:
Table -cabinet set with
moving -coil loud -speaker, needing only aerial and earth ex-
TYPE
ternally.
of stations.
need of the
listener without a
mains supply for
really good
on the market
I O
FOR such
ANODE
CURRENT :
amperes.
most people.
Tone control
76
Wireless Magazine,
E "T
IHN
THAT set of yours on the table
over there, with its aerial taken
to the tree at the bottom of the
garden-how much of its good
performance is due to the set and
how much to your locality ?
I doubt whether you can tell me.
If you can, you know more about
wireless than most experts.
The point is of considerable
interest at this time of year, when
portable sets are taken afieldmostly in cars, of course, for the old
idea that a portable set can be comfortably carried by hand for any
distance is retained only by those
who have never tried to carry one !
The chief point about a portable
set is that it can be set down anywhere and made to operate without
the necessity of connecting an aerial
and an earth to it-the frame of
wire which is the equivalent of the
outside aerial for pick-up purposes
being contained within the case.
Ever since portable-or, better
expressed, self-contained setsbecame popular, I have' had a regular
flow of letters from readers who have
been puzzled by certain matters
connected with their performance,
and for this reason it occurred to me
that a few notes on the subject
might be helpful.
Many Vicissitudes
The wireless waves sent out from
any broadcasting station experience
many vicissitudes before they finally
affect your wireless set. They may be
reflected and absorbed, partially at
any rate, in half a dozen different
places before they reach your
receiver and, occasionally, due to
certain contours of the land, they
may actually be concentrated at a
point where you happen to be.
If you draw a circle fifty miles in
radius around a broadcasting station
and try out your portable set at a
hundred different places on this
circle, you may get a hundred different strengths of signal.
So do not get worried if, on the
"T
WV
AT
C HANG E
E R H/Al lITS
II
By
PERCY W. HARRIS,
M. Inst. Rad. E.
one hand, when you take your transportable set with you in the car and
use it on some high ground or
common, you find that reception
conditions are either much better or
much worse than at home.
If they are much better than at
home, this may be due to the fact that
buildings or high trees are electrically
shading your reception area. Big
buildings, such as the Crystal Palace, zero.
for example, may " shade " a considThe direction of best reception
erable area in the immediate vicinity. from one station is not necessarily
On the other hand, you may be so the best direction from another, for
situated that your house is on the. which reason the non-directional
top of a hill with no trees about, no properties of the ordinary aerial (or
big buildings, no visible sign of the mains type) has made this latter
electrical obstruction to the waves, the more popular.
and yet-I have known several such
Rejuvenating An Old Set
cases-your reception may be definitely poorer than some districts in a
Many a portable set which has
valley nearby which seems to be been put by as being insufficiently
badly screened.
sensitive can be made useful again by
I have even known two districts in connecting to it a small aerial of the
the same town, one at the top of a ordinary type. When a set has to
hill and one at the bottom, differ so cover both medium and long wavemuch that reception is ten or fifteen bands and has reaction on both,
times as good at the bottom of the there are usually a number of conhill as at the top.
nections to the frame, but one of
If you have an outside aerial and these connections will be found to go
it is reasonably high you may find to the grid of the first valve.
little difference in reception whether
To this connection join one side of
you have the set itself in an upstairs an aerial compression condenser with
room or one downstairs, provided a maximum of about .0001 microyou have a sound earth connection in farad capacity, the other terminal of
each case.
which should be connected to a
With a portable or transportable length of wire.
set, however, with the small frame
This can be joined to an ordinary
contained in the case or lid, there outside aerial and an earth connection
may be a tremendous difference in can be made to the negative terminal
strength between reception in two of the accumulator.
such rooms. A big difference will
With such an arrangement you
occur even in the same room, for a will get much stronger signals than
gas pipe, electric -light conduit, or a you obtained with the frame with the
metal fireplace may be quite suffi- additional advantage that the set will
cient to absorb the waves or screen no longer be directional. On the
them when the set is immediately other hand, the tuning position may
adjacent.
be quite different for a particular
I remember one year having a station and the set will be far less
portable set ready to listen to an selective than with the frame.
1
77
August. 1933
Wireless Magazine.
August. 1933
without Wireless
Valves
A Ship
!
The Exhibition
AS far as I have been able to
observe, the radio trade is not a
particularly pious body of men, but
I should think that everybody who
has to go to Olympia from August 15
to 24-the dates of this year's
exhibition-is praying for a cold
spell.
This year the show is about a week
earlier than it was last year-and then
on several days it was unbearably
hot. I have heard rumours that
special cooling arrangements are to
be put into operation. Let us hope
that they are effective
By the way, although I have not
heard any details, I gather that there
will be something rather out of the
ordinary to interest visitors to the
" Wireless Magazine " stand-which
is No. 10.
1
Permeability Tuning
Personally, I am very much
interested in the possibilities of
permeability tuning. In case you
do not already know, I had better
explain that this system is based on
the fact that an iron core moved
about inside a coil will vary its
inductance-and therefore its wavelength-just as effectively as will a
variable condenser.
It seems to me that it should be
possible to make a movable iron core
in a very much neater and more
compact mechanical form than even
the smallest of variable condensersand it should also, in the long run,
prove to be cheaper.
By the way, at Olympia you will
see a number of really midget gang
condensers. Some of these have
build another.
Still, I did get him to say that he
would think about trying a new
single-valver with modern parts to
see what it would do. It is no use
having a loud-speaker as it interferes
too much with men trying to get
a rest when they are not taking
watch.
London, W. C.1
BM/PRESS
LWireless Magazine.
Augusr, 1933
10
79
1933
actors
Fig. 2.-Skeleton circuit for tone -compensated volume control. Note the
following values: AB, 30,000-ohmpotentiometer (tap T at 6,000 ohms from bottom) ;
L, air -core coil of 50 millihenries and
500 ohms; and C, .5 microfarad
No Hard-and-fast Rule
One can see at once that there is no
hard-and-fast rule as to the choice of
a particular curve because whatever
position one is in a room, one gets a
different strength, but, given such a
correction adjustable at will and also
another adjustment for pure strength,
one could play about with these until
the most pleasing result is obtained.
There seems to be no doubt that,
particularly when we want to hear
weak stuff, a definitely more pleasing
effect can be obtained by making the
output curve one of these scooped -
out characteristics.
Talking-picture Work
The idea is of considerable importance on work outside radio. I have
noted in talking-picture work that if
one is sitting in a projection theatre,
and the projected picture is of a
certain size, to obtain the illusion
that the people on the screen
are actually talking the size of the
picture must be matched with the
volume of the sound moderately
accurately.
A serious divergence from the best
strength takes away the illusion and
then we do not properly connect the
speech with the picture.
If home talkies ever seriously come
into vogue the chances are that the
average household will never be able
to have more than quite a small
picture with quite small figures of
:-
OUTPUT
ll
PICK-UP
80
connected in parallel with the 6,000 ohm section and comprises an air core inductance of 50 millihenries
and a .5-microfarad condenser. The
resistance of the choke is approximately 520 ohms.
The inductance and capacity are
broadly resonant to frequencies in
the neighbourhood of 1,000 cycles,
as shown in Fig. 3, the upper curve
of which shows the frequency characteristic of the volume -control system
with the movable arm set at the
high -potential end or point of maximum output.
The lower curve is the frequency
characteristic for the point of maximum compensation. The response
characteristic of the system for other
adjustments will be located between
these limit curves, approaching, in
shape, the curve to which it is more
adjacent.
MAXIMUM
VOLUME
MAXIMUM
COMPEIISATIOH
9
30
100
1000
FREQUEOGY (CYCLES PER
Fig. -3.
4000
SEC.)
When the arm of the potentiometer is at the top maximum compensation occurs and the voltage/
frequency characteristic is determined by the impedance/frequency
characteristic of the compensation
circuit.
Here the signal frequencies in the
mid -range are highly attenuated in
comparison with the low- and high frequency registers and the degree of
compensation is determined by the
constants of the shunt network.
In the circuit described above
the attenuation of voltage, with
the arm at the top, is 14 decibels
with the compensation circuit disconnected. Connecting the compen: ation circuit results in an additional
attentuation.
Reducing the volume -control setting below the point of maximum
Wireless Magazine.
compensation has little effect on the
shape of the voltage/frequency
characteristic of the volume -control
circuit.
Care must be exercised in determining the value of the tapped portion of the volume control in order
that subsequent circuit constants are
not affected when the volume control
is adjusted to positions below the
point of maximum compensation.
Low-volume Levels
A practical difficulty experienced
with this system at low -volume levels,
where the low frequencies are exaggerated to give the desired acoustical
effect, has been that of disagreeable
low -frequency distortion introduced
from certain broadcast signals; this
has necessitated the addition of a
suitable filter to attenuate frequencies
below 70 cycles in order that such
disturbances as interchannel beat and
station -generator noises do not mar
the quality of the programme being
received.
It is apparent that if audio compensation becomes a standard feature
in broadcast -receiver design, care
will have to be exercised in broadcast
transmitters in order to minimise
these low-frequency disturbances.
Some
Quality Hints
August. 1933
THE STICKER
The Sticker is, as you will note,
A most intrusive sort of goat,
A cross between a goat and
ass,
Wireless Magazine.
August, 1933
: :
WEARITE CLASS -B
TRANSFORMER
Lissen Intermediate-
::
Peak Condensers
MAKERS
Common Cathodes
and Anodes
Two of these valves have a common cathode, while the other two
have a common anode.
When one mains lead is positive
the current flows in one direction,
while during the next half cycle the
direction of the current changes. It
is thus made to go through the load
in the same direction each time and
gives double -wave rectification.
ATTRACTIVE PROPOSITION
The new Wearite class -B transformer,
with its tapped secondary for use with
different valves, is very good vaine
82
Wireless Magazine.
OSBORN
SPECIFIED
UTILITY
CABINETS
Tunes the
TYERS
IRON -CORE
THREE'
August. 1933
Again
CHOKE
SPECIFIED FOR THE
D. C. CALIBRATOR
The incorpora-
tion of the
"DAVENSET"
Choke in the
"D.C. Calibra-
tor "
of
is
typical
the
high
reputation
-DAVENSET"
`tains
Trans-
ormers
design.
The
home -set
constructor
will find in
them
tho roughly reliable and sound
equipment of
the
highest
quality
and
most original
design, which will make a
material
contribution to
the success of his set.
driver.
copy
are specified by
27/6
W298
2Z
and
Chokes enjoy
amongst
experts in radio
Utility condensers
E.
R.
MORTON Ltd., 22
Circus, E.C.4.
WRITE FOR
of " Mains Trans-
'
Belmont
Wireless Magazine
83
"
when
writing to advertisers
Wireless Magazine.
August. 1933
NEW APPARATUS
Continued from page 82
TESTS OF
neighbourhood
of
12,000 to 17,000 ohms
for general requirements. Lower values
milliamperes,
84
:-
Driver
H.T.
valve.
volts.
Anode load
(total).
L2
120
120
135
17,000
11,500
12,500
P220
P220
Watts
output.
Input to
1.0
1.4
2.65
4.16
4.8
2.35
driver.
Driz er ratio
(overall).
2:1
1.5:1
1.6:1
PEAK ELECTROLYTIC
CONDENSERS
(a) 4-micro farad wet electrolytic con(b) B-microfarad wet electrolytic condense,.
APPARATUS :
denser.
TYPE : W.
PRICE : (a) 4s. 3d., (b) 4s. 9d.
MAKERS: Wilburn & Co.
IWireless Magazine.
August, 1933
POLARRAE
The Polar range of condensers
covers every possible need-and
more, every individual condenser
is a precision made instrument
one in which set designer,
manufacturer and amateur
alike place implicit trust, Be
guided and use " Polar,"
Send for Leaflet.
POLAR
DIFFERENTIAL
The condenser with
an
Insulated spindle. Constructed with the highest quality
materials.
Smooth action.
Complete with knob.
.0001, .00015, .0003
y1u1111
with
permanent
curacy.
ac-
.0005, .0003
/
616
w..
A PERFECT
LIST
OF
INTERESTING
CHOKE AT
PRODUCTS
FREE
LOW COST.
"KINVA"
ON
REQUEST
STANDARD TYPE
SCREENED H.F.
CHOKE,
for H.F. or
DET. Anodes,
2/9
POSTLETHWAITE
ACTUAL
BROS.,
SIZE
en you ui
KINVER, STOURBRIDGE.
THE
..
SELF CONTAINED 4
build with
spare
UBILIER
SMALL
ADVERTISEMENT
RESISTANCES
DEPARTMENT,
"AMATEUR WIRELESS,"
58-61, FETTER LANE,
LONDON, E.C.4
Dubilier Condenser
There
is news in the
"
Wireless Magazine
85
Co. (1925)
"
advertisements
IWireless Magazine.
August.
1.933
Electronic Music
Wireless Magazine.
August, 1933
need
MAINS
UNITS
and
KITS
F. C.
HEAYBERD
& CO.,
Euse
FinsburySt.,
London, E.C.2.
10
(Minute from
Moor-
ROLA
ROLA
How can
How can
32/6 YOUR
for
MAINS
IRON -CORE
and Specified
Exclusively
TYERS
the
THREE
knife-edge selectivity and high amplification
attendant upon the use of the amazingly efficient
new Nucleon coils used in this receiver have called
for a specially designed Rola speaker. Rola have
produced a special speaker exactly suited to the
characteristics of this outstanding set. Write to -day.
The
What resistance do
COUPON
Co.
need?
Book
Ltd.,
To The
IIN"alu Farm
RO LA
Radio Reception
for better
?-
eliminate Interference?
PROBLEMV- this
SPEAKERS
ALL-BRI%J 17
Wireless Magazine
87
NAME
ADDRESS
CONDENSERS'
"
W_M_8/33_
Please
write
in block
letters
Q
when
writing to advertisers
2978
Wireless Magazine,
1DM
August~ 1933
THE
EST OFTH[\/AVES
By JAY COO TE
: :
BELGIUM
Belgian listeners are very
perturbed at the news that
the government will shortly
raise the annual tax on
radio receivers. So far the
amount paid yearly has
been sixty Belgian francs
(roughly 10s.), but as a
deficit in the balance sheet
of the Institut National de
88
AGAIN
for
Wireless Magazine.
1
August, 1933
exclusively specified
the
TYERS
IRON -CORE
THREE
SMITH'S
ACCU
LATO
M U
see it with
GANODEX'
SMITH
&
Vide
CRICKLEWOOD,
LO
N D O N,
N. W. 2.
ELECTRADIX BARGAINS
CELLS.
we
MICROPHONES.
MIC
Button
TELESCOPES.
"M"
ELECTRADIX RADIOS.
18,
10
full
of simple, pictorial
diagrams which anyone can
follow, showing easy alterations to make your wireless
set right up to date at
minimum cost. Illustrates
numerous "gadgets" of
use to every set owner and
constructor.
Write Dept.
"B,"
"
MEANS
CS,
O
S
Wireless Magazine
89
"
more money
vv
D Wireless Engineering
Advertising
D Radio Operating
Salesmanship
Commercial
Radio Servicing
Serer
Addreae
advertisements
Ige
Wireless Magazine,
August, 1933
HUNGARY
The first monument erected to the
memory of a director of broadcasting
will be unveiled this year at Budapest.
Its aim is to commemorate the work
of Dr. Ern Szts, the founder and
first director of the Hirmondo
broadcasting company, whose sudden
death took place last December. The
official ceremony, which is to be
relayed to listeners, will take place
on the first anniversary of his death.
ROUMANIA
90
Wireless Magazine.
August. 1933
SPECIFIED
forthe "Wireless Magazine"
"SELF-CONTAINED
FOUR"
We're
Fluxite
your RADIO with you
u..e
Solder
--without any qualms
the rdiahle pair: For if WE are
you
Famous for soldering- -music stillnear
hall' her
known everywhere
charma I"
soldering is needed.
FLUXITE
IT SIMPLIFIES ALL SOLDERING
Fluxi'r
L ,i
Short-wave reception
now possible with
most receivers!
Short-wave stations can be tuned in with practically every receiver when fitted with an Eelex
Short-wave Convertor.
Programmes from
Australia, America, and other distant countries
are brought in without trouble even by those with
little or no experience of Short-wave reception.
You can spend many thrilling hours tuning in
distant countries, and your friends will be amazed
at the remarkable increase in the range of your
set
with
an
J. J. EASTICK
EELEX
HOUSE,
118
-
&
Circuits
densers.
It may interest you to learn that I
have made up a Ferrocart receiver
using a screened grid calve and one
of your Nugang 3 type condensers.
and at the above address in North
London I find no difficulty in
separating Krrigswusterhausen from
Radio Paris and Daventry, with a
similar performance on the Short
Senior
Permanent
Magnet Moving -Coil Speaker
PM4 CLASS
42I -
I shall
pleased to demonstrate
be
if you
are interested.
Again thanking you for a firs.class condenser.
Yours faithfully,
(Signed).
SONS
NUGANG
Bunhill
-
Waves.
Row,
E.C.I
Phone: Metropolitan 0314 (6 lines)
LONDON
The
"
Wireless Magazine
91
"
hs.
un4II
11
Wireless Magazine.
August. 1933
Elizabethans
92
Wireless Magazine,
August, 1933
NOISES
PRICES:
3/6 ea.
3/6
- 4/6
-
76
Send
Famous Maker's Offer
Radio-Gram
r n CABINET
for RK /
SEVEN
FREt
VATa'
(OR
19/.
MOH
TnIAL
I)
35/-. to 15.
Ph. tojraphs nad List FREE.
MODELS FROM
PICKETTS PAL;ease'
M.G.. Albion Road, Bexleyheath.
Write for
P218
screened flex.
Chassis
5 -.
i/
ERIE
RESISTORS
Cclone-
S.E.1
BELLING -LEE
PICK-UP
27/6
MIDDX.
CO.,
Model A.
Post Free
ERIE- VISE i t !
Dril!ed
Publication
3 AND
THE
IMPROVED -volt accumulators
Self -generating Trickle -charger Kit keeps "TONIC"
2
fully charged. Electric mains and charging stations unnecessary. Ideal for remote places. 7/- each; postage Od.
Particulars, testimonials, with pleasure.
PEAKCONDENSERS
Specified for " THE
Type W
8 mfd.
450
I mfd. (,5
1/10 each ... I/10
I
mfd. @ 2/2 each ... 6/6
2 mfd. sc 2/9 each ... 5/6
ELECTROLYTIC
2
2
each
NORTHERN AGENTS: W. ANDREW BRYCE & CO., TILE ST., BURY, LANCS.
SELF-CONTAINED 4
Kit
first specified comKIT "A" Author's
ponents including Peto Scott metal
of
YOJxs
uro
Mt
I1/
oust' ton
,
PRICE 6d.
"
Holder
Working
4/9
THREE
TYPE A4
volts D.C.
Peak
A.C.-D.C.
if
by
return.
KIT
"P,5"
1 Set of Valves
..
77 CITY ROAD, LONDON, F,C.1.
62 HIGH HOLBORN, LONDON, W.C.1.
you mention
93
"
Parts
Wireless Magazine
"
.. 2/7/6.
1 Peto -Scott Cabinet
Tel.: Clerkenwell9406/7
Holborn 3248
19/8.
Wireless Magazine.
August, 1933
Birmingham.
The outfit consists of materials
needed to set up four cells that will
obtained.
94
Wireless Magazine.
YOU CANNOT GO WRONG
IF YOU USC
August, 1933
1931
...
...
...
AW308
...
B.B.C. One-valver
...
...
...
...
...
...
... AW304
... AW387
... AAA/354
CALIBRATOR
matter.
...
...
...
...
...
...
...
...
...
...
...
...
...
...
WM295
WM299
WM312
AW357
AW361
AW364
AW37I
.. AW374
... AW377
... AW388
WM288
WM294
The
..
...
...
"
" containing descriptions of
Magazine
less
The
TABLE QUAD
valves.
(Lanes). -1 thought you might be
interested to know how pleased I am with the Calibrator. I have adapted the set for all -mains working
and am extremely satisfied with the results obtained.
I can log over forty-five stations at good loud -speaker
strength.
Blackpool
The
WIZARD
WM296
WM306
WM308
WM309
WM314
WM3I8
WM327
WM328
WM330
AW343
AW360
AW368
AW366
AW372
AW378
AW381
AW383
AW384
AW386
WM273
WM279
WM290
WM292
... WM293
... WM300
.. WM303
...
...
...
...
The W.M.
SHORT-WAVE SUPER
Swansea.-Have built
ports,
D.
short-wave
E6 IOs.
without
Circuit:
Price
-valve
of
sec:
valves.
Walthamstow (Essex). -1
" W.M." Short-wave Super.
Self-contained Four
No. W M331
...
...
...
...
...
9d.
(SG, D, Pen)
...
6d.
" W.M."
...
...
...
... WM269
... WM272
... WM280
... WM284
WM32I
WM326
WM325
AW363
AW365
... WM256
... WM305
... WM3I9
WM282
WM291
WM322
AW35
...
...
Class -B Mains Unit ...
...
"A.W." Trickle Charger ...
...
Add-on Band-pass Unit
Plug-in Short-wave Adaptor
...
...
...
...
...
... WM287
...
...
...
...
WM324
AW352
AW359
AW382
El
95
Wireless Magazine.
August, 1933
NOTES AND NE
Continued from page 94
BLUEPRINT
COUPON
Valid only until August 31,
1933 (or until Sept. 30,
1933,
r
..
ai
..
If you
93
13
3
87
89
93
Fluxite, Ltd.
..
..
11, 85
..
89
..
91
Cover
H
Heayberd, F. C., & Co.
..
..
Cover iv
Cover iii
F'
Jackson Bros.
9
3
..
..
..
ii
87
89
91
1.
INFORMATION
&
..
Smiths
..
93
13
'
83
9
83
93
93
85
n '
..
..
89
93
..
..
89
87
11
COUPON
Valid only until August31,
1933 (or until Sept. 30,
1933, for overseas readers)
ADVERTISERSPage
full-size blueprint of
any ONE of the sets constructionally
described in this issue for half price,
want
INDEX TO
Varley
..
..
..
..
li
91
93
83
93
85
14
&
Co.,
London, E.C.4, by The Sun Engraving Co., Ltd., London and Watfoid.
Printed for the publishers, BERNARD JONES PUBLICATIONS, LTD., 58-61 Fetter Lane, (Victoria),
Sydney (N.S.W.), Brisbane (Queensland), Adelaide (S.A.),
Colonial and Foreign Agents : AUSTRALIA-Gordon & Gotch, Ltd., Melbourne
71-75 Boulevard Adolphe Max, Brussels. CANADA-Gordon & Gotch,
Ltd.,
&
Son,
Smith
H.
BELGIUM-W.
(Tasmania).
Perth (W.A.), and Launceston
& Son, Ltd., 248 Rue de Rivoli, Paris. HOLLANDH.
Smith
Paris, 2me.; W.
Ltd., Toronto. FRANCE-Messageries Hachette, 111 rue Raumur, Ltd.,
Wellington, Auckland, Christchurch, and Dunedin. Sole Agents for SOUTH
Meulenhoff & Co., Amsterdam. NEw ZEALAND --Gordon & Gotch,
Gotch,
Ltd.) August, 1933.
&
:Gordon
AFRICA-Central News Agency, Ltd. (London Agents
96
Wireless Magazine,
Purveyors of
Electric Lamps
By Appointment
August, 1933
EDISWAN
The na.ne that
Manufacturers
and
Purveyors
of Electric Lamps
By Appointment
//i//,4,)
''
A g
kiiioi
;t
q
,
7z':,1
i.}r.:tp:_-+_+;.-..,_1.,A:
..
YOUR DEALER
HAS AMPLE
MAZDA
STOCKS!
PD220
(with standard
7 -pin
base)
PRICE141
155
Charing
Cross
Road,
W.C.2
V.210
4#1
flcik
POSsibIe
is a
new principle applied to this radio -gramophone. Firstly, it makes it possible to provide
tone and volume equal to an all-mains
set. Secondly, the life of the battery is
considerably lengthened as the current is
automatically reduced when the set is playing
quietly or during an interval.
Surprising
new features
Name
Address._..