HONG KONG DAILY PRESS, THURSDAY, JANUARY 15, 1931.
010
FEATURES
THE MAINS-DRIVEN SET,
ECONOMICAL AND EFFICIENT.
A FEW ADVANTAGES EXPLAINED.
If you have a mains-driven set or contemplate building one, you have distinct advantages over your bat tery, using friends in the question of valves. The advantages aro, however, not wudicness of choice, because there are very many less mains valves on the market than battery types, but those available are exosedingly efficient.
It is possible with a mains-driven et, with valves of the indirectly. healed cathods, type, to get a far higher magnification per stage than it is with the battery type.
In the case of the directly heated valves with the A.C. put straight through the filament, very much the same characteristics as the battery
Aypes are obtained, but it is with
High Mag. LF., Typea.
The low-frequency stages do not hold out so much choice in the types of valves, but the ordinary A.C. L.F. valves are all suitable here, whilst for the output stages you have the possibility of such valver
If you have not looked critically at your accumulator of late, inspect it now and see that the liquid inside covers the tops of the plates
.
Never leave an L.T. battery stand- as the ACP., which has, an im-ing in a discharged condition, but pedance of something like 2,050 ohms and a magnifontion factor of always get it recharged as son e its voltage falls below the safety lovel.
10.
Such a valve has not a very big grid swing, but it will give a tre miendous output power for the in put, and as a lond-speaker valve it takes a great deal of beating,
In operating an A.C. indirectly. heated valve it must not be for gotten that the cathode must be
taken to a neutral point on the the AC indirectly-heated valves.T. winding of the transformer. we want to deal with.
The S. G. Valves,
A two-volt LT. battery needs recharging when its voltage has dropped to 1.8, a four-volt battery when the voltage is 3.6, and a six- volt battery when the voltage falls
to 5.4:
*
If the transformer is not centre If your reception varies in tapped, then a 400 ohm potentiostrongth suddenly or becomes dis- meter should be placed across it torted without your set being touch- and the slider taken of the valve. This is essential ifed the probability is that one of hum is to be successfully eliminated. Your neighbours is using too much
the cathode
| reaction.
TO-DAY'S WIRELESS
PROGRAMME.
If you so a screened-grid stage you will find you have the A.Ö. S.G. Mazda, which has a magnifics tion of 1,200 with an impedance of
The Hontor Connections. only 600,000 ohms. The A.C. S.G. Cossor valve, with mutual conduct-
When wiring up the filament, or anco of over 2, the Mullard, Osram, rather the hentors, of indirectly- Marconi, Six-Sixty. All of which heated cathode valves, or of any are capable of giving very highA.C. valves, it is essential that magnification, much higher than is either lend covered wire be employ ponsible with the battery 5.G. valve, ed, or twisted flex be used, other
This being the case any user of mains valves must screen his II.F. wise pick-up may take place be- singe very completely to make the tween the heater leads and other most of the magnification, Obvious connections and thus causes a hum. ! For economy of running there is ly if a valve has tremendously grent nothing to beat the A.C, valve, and magnification powers, it is liable to cause instahilly or feedback it well designed three valver, using
11.30 a.m.Chinese programme. A.C. indirectly heated valves is the screening ja not properly enrried capable of giving results compar:1.30 p.m.-Weather report, 'local
12.30 p.m.-European programmé.
four-valve battery operated set.
out.
די
If you are changing over tromble with those of a really good battery to mains do not forget to add a little more screening,
AD, Detectors,
The A.C. detector valves are also more efficient than the buttery type. Here you have to add positive bias for lenky-grid rectification, for in this indirectly-heated valve you have no positive leg of the flament to which you can connect the return end of your grid-loak. Therefore, the grid-leak has to go to 1 volts positive on a grid-bins battery, the negative of which is taken to the cathode. The heater, of course, goes straight to the secondary of a transformer, which is supplying A.C. sually at 4 volts, to the valves.
SOME USEFUL HINTS.
BROADCAST BY Z.B.W. ON 35S METRES.
11 am-Stock quotations,
time and Rugby Pross news. p.m.-Close down.
5 to 8 p.m.-European programme of Columbia records supplied by fears. Anderson Music Co.
Sets with three, four or five valves 5 to 5.30 pm often need a separate H.T. feed to the detector and power (or amper- power) valves if instability is to be faraided.
The
•
Musical Comedy. "The Merry Widow "-Vocal gems. -Columbia Light Opera Com- pany. ma Orchestra
When a set has a slight tendency "Sally"-Selections.-Regal Cine- to howl, simply reversing the secondary lends of one of the LF."Follow Through "—Vocal_gers.—
Columbia Light Opera Co. transformers may cure the trouble.
3.30. to 6 p.m.-.
One of the advantages of an anti- motor-boating device is that it can be fitted externally, if the set is of
type in which it is difficult to interfere with the internal wiring.
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“Dealers, Storaz, 252,
Variety.
· Orchestral - Gaiety Echoes."-- Herman Finck and his Orch. Humorous Duct" Sweet Caro-
line."The Two Gilberta.
Humorous Duet Three Blind
Mice," --The Two Gilberts. Chorus "Ragtime Mamorica."
The Jolly Old Felliwa.
Orchestra Tesoro Mio"" (Be- cucci)-Tho. Londen Novelty
Orchestra,
Orchestral-"Amina
(Egyptian
Seronade) (Lincke).-The Lon-
don Novelty Orchestra.
d to 6.30 p.m.-Children's program-
mc.
6.30 to 7 p.m.-
Band Selections.
"Community Medley" (arr. De
broy Somers).-Debroy Somer's
Barid.
"A Hunting Medley" (arr. Debroy Somers), Debray Somer's Band.. "The Rose"-English Selectione.— H.M. Grenadier Guards' Band. Classical Memories"(arr. Ewing).-Debroy Somers'. Band.
7 to 7.18 p.m.-*-*
Das Sweet and Low" (Ten- byson and Barnby)-Boy and Girl, Sopranos.-Evelyn Griffiths and Master. Charles Hawtry. Duer Home Sweet Home ... (Payte und Bishop). Boy and Girl Sopratios. -Evelyn Griffiths and Blaster Charles Hawtry. Violin - Solo - 4 Caprice
nais-Naoum Blinder. Song:-- Why Did Yon Bin My Heart Awake (From Fre- derica") (Pepper and Lahar). Lea Beidl (Soprano),
7.15 to 8 p.m.
Orchestral.
Vien-
"Pétilo Suite De Concert" (S Coleridge Taylor).--New Quect's Hall Light Orchestra. "Idylle Bretonne " (Gennin).-The
Bournemouth Municipal Oroh. "Fluttering Birds" (Gebnih)-
The Bournemouth Municipal Orchestra.
"Gipsy Suite-Lonely Life The
velers (E. German).-The Plaza
Theatre Orchestra, nes bass
8 p.m.-Chiness Studio concert.
0p.m. Weather roport, local time,
otch 10.30p.m. Close dora,
HAVE YOU HEARD THESE?
Here are lets of long-wave and short-wave stations which should be picked up by anyone in Hong Kong who has a moda rately good sat suitable for ra colving such signals, Success in picking up these stations also. depends very largely upon fay ourable atmospheric conditions. Readers are invited to add to this list should they succeed in picking up any station not in- cluded in althor of these liste,
STATION
CALL BIGH
LONG-WAVE STATIONS.
Wave longth
(Metres) Station
Krto.
Kilo
Call Sign cyclo K:21. B. 1,153 260. Manila. 277 Shanghai K.B.M.8.. 1,085. 280 Tientsin C.R.O. 1,070 310 Shanghai: BBC 320 Poping
C.O.P.K. D45 345 Tokyo 3.0.A.E. 870 353 Hiroshima J.O.F.K 3 Hong Kong Z.B.W. 347 Bombay V.U.B. 840 361 Sapporo JO.LK. 890
366 Keijo 378 Nagoya 370.4 Calcutta 380 Kumamoto 330 Bendai 305 Dairen 308. Rangoon · 400 Genka
410 Canton
413. Manila
246-
J.O.D.K. 820 .J.0.0.K, 810
800.9 V.U.C J.O.G.K.: 700 J.O.H.K. 770
·J.D.A.K.-760 V.U.R. J.O.B.K. C.M.D.. KZ.B.M,
750 789
SHORT-WAVE STATIONS.
Ta (Hoxo Koxo) OF WORKING
484 Mon., Wed. & Fri, 0 p.m. & 2 n.. 4,990 610 p.m.
47.85 Dobintz (Germany)
7,810 Not regular
The Dally 1,
9.108 Tues. & Fri., 9 p.m.-1 am.
D.280| Not regulax
9,603 Not regular.
8, 1314
W2XA.F. 9,530 Daily Sat. 3 am, & 10 am.
9.620 FT. 8 a..
9,600 Not regular
A,B..
6012 Khabarovsk (Russia)
B.A.07.
56.7
Nauen
A.G.J.
5,291 Not regular
50.
Moscow
E.F.N.
8,000 | Ton, Thurs Sat 5 p.me
43.5
Bome
1.M.A.
6,896 Bunday midnight
42,
Porth
6.A.G.
7,143 Daily 0.80 p.m. &.11 p.m.
41.3
Singapore
V.8.1.A.D.
98.8
Kootwijk (Holland)
P.C.L
37.
Bangkok (Siar)
HSSP.
$2,6
Bydney
2.B.L.
31.65 Melbourne
31,48 Schenectady
81.20 Eindhoven (Holland)
PCJ.
31.28 Sydney
2.F.C.
31. -Nairobi (Konys)
*LO
9,677 Midnight dally
28.5 Bydney
2.M.E.
10.526 Not roguiar
21.8
Bandoong
P.LE
11,000
24.5
Manila
K.LIB.
12,240 Nightly
23.30 Sobenectady
WAK.O
22,830 4 401. Wol, Fri, Bat.
18,88 | Bandoeng
PLO..
18.4
Kootwijk (Holland)
P.CL
17,4
-Bandoeng
18.0
Bangkok
10,8
Kootwijk (Holland) ;
1674. Bandoning
PC.K. PLE
15,6 | Nancy (France) 13.93 Pittsburg
19,351 Dally 8 A.
W.6.X.K.
21,540 Not regular
25.68.Chelmsford (England)) 6.8.W.
[Allowance must be peau countries, which
P.L.F. H.S.1.P.J.
Midnight 3 one daliy
11,761 7.30 p.m. & 8 am, daily, ercept
Saturday and Sunday
16,102 Daily 6.30 p.m. to midnight-
10,804 Daily 7 p.m.
17,250 Daily 8 pm, to midnight
17,761 || Bunday: 7 pm, & midnight
18,404 Each afternoon
19,220 | Dally 6,30–7 p.m.
A
made for "summer-time" in most Euro-
MUSIC FROM MANY COUNTRIES
one hour ahead of trus, tima.]
by wireless with. TELEFUNKEN 40
Long range All-Electric receiver. with station selector for use with batteries or lighting mains.
with TELEFUNKEN LOUDSPEAKER
ARCOPHON
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Including Marda Valves (the beel Brush Values)
Special B ELIMINATOR for any domestic set or made to order for any requirements.
For
perfect réception
use
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RADIO batteries made by new process minimis- ing deterioration "PERTRIX" 150, 100, 60, .45 volte and C. batteries.
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