HONG KONG DAILY PRESS, THURSDAY, MARCH 19, 1931.
ARCTURUS
The Famous Blue Tubes
For Better Radio Reception
Exclusive Features -
LIFE-LIKE TONE.-When you purchased your radio set, you expected to get clear, life-like reception. That depends on the tubes you use! The exclusive, advanced design of Arcturus Tubes eliminates mechanical background noises-every note, every word, comes in with a vivid Life-Like Tone. With a complete set of Arcturus Tubes in your radio, you know you'll get unusually clear, brilliant programmes, SECOND ACTION.-Arcturus Blue Tubes in your radio set bring in programmes in just 7 seconds
no annoying wait for programmes to begin. Just flip the switch, and by the time you turn the dial, the programme is there-quick, certain, as compared to the usual 30 seconds, or more, wait.
WORLD'S RECORDS FOR LONG LIFE.— Throughout the world, Arcturus Blue Tubes are proving themselves to be the tubes that have established a world's record for long life. Because they withstand exceptional overloads that often burn out other tubes. Arcturus Blue Tubes assure the user of long, satisfactory service.
Ask Us For Demonstration
&
FEATURES
A FEW MORE PRACTICAL HINTS.
DUAL-RANGE COILS: TRANSFORMER TROUBLES: MAINS VALVES: "MOTOR-BOATING.”
In many circuits a dual-range coil is used having a tap en the medium- wave coil for the serial. This tan is useful, as the selectivity and magnification are both probably better when the aerial is taken to the tap instead of to the top of the coil.
The wavelength range with A giren tuning.condenser is greater, too. This is because the effect of the capacity of the serial is reduced by connecting it to the tap. Now the advantages are not obtained when we switch over to the long wavelengths, for the reason that the aerial is not connected to a tap on this coil.
Simplified switching is respon sible, and you cannot obtain the best possible results without mak ing the medium and long-wave length oircuits in the best way. In the Binowave coils separate long- and medium-wave aerial connec tions are used in order that the efficiency of the coils shall be high on, both wavebands.
Compact coils are sometimes not very efficient, although perhaps they are quite good for their size, and this point of the best aerisi connection is bound to crop up. Sometimes a single separate aerial winding is used for both wavebands, but here again something is lost in the interents of simplicity and cheapness.
THE SINCERE Co., LTD. directly heated power valve in an
DISTRIBUTORS.
put are available
This is not true when a D.C. eur- A directly-heated valve is a more rent is passing through one of the simple job than the other type. Awindings as well as the AC.
Transformers and phoking calls centre-tapped transformer or a
should have the highest inductance potentiometer of low resistance may
wire
be used, and grid-bins may bo ob.undor working conditions. The tained by including a resistance in greatest inductive effect is obtain- the high-tension negative return ined when the direct current is small or when there is none at all. It is the usual way. The centra tapi possible to obtain a fairly uniform- must be fairly accurate, or a hum inductance over a range of direct currents by carefully proportioning will be heard.
the core, air gap, and number of turns. iMotor-Boating."
Low Losa.
Although low-loss constructions are not now given as much atten- 1 Lion as a few years ago, the nud for avoiding the use of materials having doubtful electrical proper tiek remaina.
Cardboard is sometimes used for coil formers. This may be satis factory, but will probably not be unless it has been carefully treated Good quality ebonite and bakelite formers are worth using for coils to be fitted to a set of reasonable effeiency.
Transformers and Chokes,
It is sometimes supposed that the iron core of transformers and chuking coils ought to be so well made that air gaps do not exist.
WIRELESS PICTURES FOR
SHIPS AT SEA.
A POSSIBILITY OF THE FUTERË.
Frequently a set which appears work very well when an output choke filter is used," "motor-bonts" badly when the filter is taken away and a speaker transformer is fitted. The filter oircuit in practice tends to stop varying currents produced by the last valve from entering the high-tension supply. It is the lower frequencies which usually cause motor-boating or oscillations, and when the choke is not
good one trouble may to experienced. When n, transformer is used the circuit is usually more prone to "motor-boat," J the protection afforded by a good output filter circuit is not present,
Such
vices over long distances. sérvices are being used for the transmission of newspaper illustra tions, fashion drawings, financial statements and advertisements from" one country to another...
The following notes on the pre- Picture, or facsimile, transmis sent situation indicate that while the future may hold considerable sion by wireless is now an accom-potentialities in this sphere, further Main's Valves,
plished fact, and Marconi engineers technical and commercial advance are necessary before anything in Should one use a directly or in- have designed modern types of
the nature of a regular and reliable directly heated power valve in an equipment which give excellent re-service is practicable for shipping: A.C. get t
(Continued on Page 3.) Given 1 good and suitable Aults for fixed point-to-point eer. directly-heated power valve the hum is negligible, being hardly audible. The Kharacteristica are as good, as a rule, as those of the indirectly-heated type, and valves working with an anode voltage of 200 and giving a good power out-
HAVE YOU HEARD THESE?
LONG-WAVE STATIONS.
AC-SG3 Set
ENTIRELY MAINS OPERATED
A sensation in 3 valvo sets, with 1 watt undistorted output; enough power for any moving coil or dynamic loudspeaker. A set that will appeal to you whether you are interested in perfect quality from the local station or clear reception from distant stations.
Price only $145.00
Including Masda Valves (the best Brituh Valves)
Special B ELIMINATOR for any domestic set or made to order for any requirements.
For perfect reception use "MAZDA" Valves, large stock newly arrived
RADIO batteries made by new process minimis- ing deterioration "PERTRIX" 160, 100, 80, 45 volts and C. batteries.
Ebonite "TROLIT" and Pressed Fibre Panels. cut, in any size. Loudspeakers, and various parts are also obtainable.
For further information apply to:-
CANTON TRADING ASSOCIATION, LTD.
UHINA BUILDING (5TH FLOOR),
TELEPHONE 24610,
TELEFUNKEN
THE WORLD'S BEST RADIO EQUIPMENT
This illustrates an All Mains set combined with loud speaker
GREAT ELECTIVITY
RECEIVES
Manila, Canton, Japan and Local Station.
For Demonstration and further particulars apply to :—
SIEMENS CHINA CO.
Office-Pedder Building, 4th Floor, Showroom-27, Nathan Road,
Kowloon.
TELE
FUN
KEN
Centon Offlou...SHAMEEN
Brakow
...GEBE, ROESE
Hare are Hists of long-waVS and short-wave stations which should be picked up by anyone in Hong Kong who has a mode rately good set suitable for re- calving such signals. Success in picking up these stations also depands very largely upon lav. ourable atmospheric conditions, Readers are invited to add to this list should they succeed in picking up any station not in- cluded in either of these lista.
Wove length (Metres) Station
200 Manila 977 Shanghai 280 Tientsin 310 Shanghai 320 Peping" 345 Tokyo
Call Kilo- Sign cycle K.2.1.B, 1,153 K.8.M.B. 1,088 C.R.C. 1,070 K.R.C. 987 C.O.P.K. 045 J.O.A.K. 970 333 Hiroshima J.O.F.K. 830 840 355 Hong Kong Z.B.W. 357 Bombay Y.U.B 361 Sapporo J.O.LE. 388 Keijo
370 Nagoya
379.4 Calcutta
640 830
J.O.D.E. 920
J.0.0.K. V.D.C
810 809.0
380 Kumamoto J.O.G.K. 700
390 Sendai
365 Dairen
308 Rangoon 400 Osaka 410 Canton 413 Manila
SHORT-WAVE STATIONS.
¡STATION
CALL Biay
1,M.A.
68.7
50.
18.0
12
41.3
67.00 Dobinte (Germany): 60.13 Khabarovsk (Russia)
Nauen Moscow Bome Porth Singapore
A.F.K.
B.A.DT,
AG.J.
REN.
[G.A.G..
V.5,1,A.B.
19,8 Hootwijk (Holland)
P.C.I
81.65 Melbourne
H.SAFJ 2.0.1. ELO
31.48 Bahenostedy
31.20 Eindhoven (Holland) | P.C.J. 81.28 Sydney
L.F.C.
7.1.0.
26.5 Bydney
27.8
37. Kangkok (Sam)
Sydney
J.O.H.K. 770
J.D.A.K. 700
V.U.R. 754
J.O.B.K. 750 C.M.B. 728 X Z.R.M. 720
Tix (Hora Kowa}
OF YORKIED
4,434 | Mo3., Wed. & Fri, 6 p.m. & 2 a.m
4,090 0-10 p...
6,291) Not regular
6,000 Tue, Thurs, Sat, 8 pm.
6,806 Hunday midnight"
142 Daily 30 p.m. & 11 p...
7,810 Not reguler
7,780 Daily 11 p.m.
8,108 Tuss. & Fri., 9 p.m.1 4.0.
0230 Not regular-
0,503 Not regular
W2.X,A.F. 9,530 Daily 7
21.. Nairobi (Konya) 2.M.E.
Bandoong
P.LE
25.53 Chelmsford (England)] 5.8.W.
P.L.F.
24.0 Marilla
20.85 Schenectady
W2X.0.
18,88 Bandoong
P.L.G.
10.4
Kootwijk (Holland)
P.4.L
17,4
Bandoopg
16.9
Bangkok...
168
Kootwijk (Holland)
16.75 Basdong
PLE
15.5
Nancy (France)
9,020 Fri, 3 1,13, Sat, 8 am. & 10 am, 0,800 Not regular
0,077 Midnight daily
10,520 Not regular
11,920 Midnight-3 m. dally 11,761 7.80 pa, & 3 am, dally, D100pt
Saturday and Sunday
12240 Nightly
1,850. Wed., Fri., Bat.
16,102 Daily 0.80 p.m. to midnight 10,804 Daily 7 p.
17,280 Daily 8 pm, to midnight
H.8.1.P.3. 17,701 Bundays 7 p..midnight P.D.K. 18,404 Each afternoon.
19,230 Daily 4.80-7 p.m.
19,851 Daily 3 a.xs.
W.8.X.K.. 31,540 Not regular
EVERYTHING (S.E.C.) ELECTRICAL
your guarantee
•
FOR THE HOME WITH ELECTRICITY
HOUSEHOLD
"Magnet
An st
example from the complete range of Men Magnet Ne Household Electric Appliances
Irons Kettles Toasters
Cleaners, Fent Fires
Washing Machines Cookers Grillers.
Appliances for the
Toilet etc
TOPLIANCES
"Magnet Pedestal Heater Supplied with ayde. fizxible cord and B.C.adaptor
TYPE T83 WL
19.03. Pittsburg
[Allowance must be made for “summer-time” în most Euro- pean countries, which is one hour ahead of trus tima.]
MADE IN ENGLAND by THE GENERAL ELECTRIC CO. LTD.
Sold by all lending Blectrical Dealer, Stores, STá !
No comments yet.
Private notes are available after approval.