Round the World on Short Wave

Radio Record, Volume III, Issue 31, 14 February 1930, Page 31

Round the World on Short Wave

THs» page is conducted in the interests of shortwave enthusiasts. A weekly log comprising notés of reception and interesting topical events

is contributed by Mr.

F. W.

Sellens

Northland, Wellington, but all.

listeners are invited to send in paragraphs of general interest.

ME. 8. T. STANTON (Christchurch) .. reports hearing UOR2, Vienna, on , 49.4 metres after 11.80 p.m., average ngth R5, very clear and steady. This & probably the station heard by Mr, Morrison. The station that Mr. R. J. Batwell (Greymouth) refers to on about 35 metres, calling WOO, will be the ss. Olympic using the call-sign G2GN. English is spoken, but I have found them very difficult to understand. The following particulars of Germany’s international short-wave transmitter will be of interest, as this station is the best heard here at presént during the early morning, and will improve as the days become shorter. "World Broadcasting’ From Germany. Germany’s short-wave "world" broadcasting station at Konigswusterhausen ifdcesen) has now begun testing, In ex,t&rnal design the short-wave plant strongly resembles the Telefunken ComPany’s standard long-waye transmitters for wireless telegraphy, while in technical construction it is Similar to that of the two high-power short-wave transmites used on the Nauen-Buenos Aires service. The new transmitter has a single wire ferial about 180ft. long, which is suspended from one of the masts of the longwave plant. The mean aerial energy, i.e., carrier wave without modulation, is 8 k.w., and the wavelength is 31.388 metres. The transmitter consists of seven units, with crystal modulation on the first. The short-wave is obtained by making use of the harmonics of a comparatively low frequency in the crystal-controlled oscillator. Suitable filters and amplifiers in the ensuing stages produce-the desired reduction of wavelength and power when the final stage is reached. The valves in the individual stages are accordingly arranged to give a successive increase in power, The first stage functions with one valve of the poweramplification type, while the second stage embodies a small transmitting valve of , the 0,75 watt class. Two similar valves L in parallel make up the third stage, and . three in parallel comprise the fourth stage. The fifth stage contains a single transmitting valve of average power (about 1500 watts), and the succeeding stage contains two valves of the same type in parallel. The seventh and final functions with two 20 k.w. water-cooled valves in push pull, Modulation on the well-known grid principle takes place in the sixth stage with the aid of three modylating valves connected in parallel. ; This arrangement of valves, of course, necessjtates separate supplies of power. A high-tension D.C. dynamo of 50 k.w. 10,000 volts is used for feeding the anodes in the last stage; the valves in the fifth and sixth stages are fed by means of 2 4000-volt D.C. machine of 5 k.w. In the second, third and fourth stages the anode current is supplied from a common source, viz. a 2000-volt D.C. dynamo of 2 k.w. whilst the crystal stage is fed by a 220-volt machine, For filament heating in all except the last stage a 20 vy. 2 k.w. D.C. generator is used. A 40 v. 5 kw.

generator heats the water-cooled valves in the final stage. The filaments of the modulating valves are heated by an alternator of high periodicity. Grid bias for the water-cooled valves in the last stage needs to be of a high value, taking into consideration the size of the valves and the high anode current, and is supplied by a special converter of 750 v. 2 kw. All machines are started by means of push-buttons on the switchboard, which is built into the lower portions of the transmitting panels. The supply current for the converter is derived from the transformer already in use at the station connected with an overhead electrical distribution system. . Besides the actual transmitter there is also a -low-frequency amplifier dealing with the speech currents arriving from the land-line, and the anode circuit of this amplifier is fed by an additional small converter. The entire installation is equipped with measuring apparatus enabling the performance of every portion of the transmitter to be checked. Reception during Weeks ending February 9 ° RA97, Siberia, 70 metres, is still received at good volume, but with a very great proportion of talk. W9XF, Chicago, 49.83 metres, can be relied upon for a good programme till 8 p.m., when they sign off with a cheery "Good morning, everybody, lots of luck. We hope to hear from you-we mean it, yes we do." Special programmes are to be given each Thursday, featuring the various States. California is to head the list. W2XAF, Schenectady, 31.4 metres,On Sunday R7-8 was the best volume which was reached by 5 p.m. Strength was only R5 at the loudest on Saturday. PCJ, Eindhoven, Holland, 31.4 metres. -A._ high-frequency hum spoilt reception on Friday morning. Volume from 6 a.m. till 7 am. was R8, decreasing to R6 by 7.80 a.m. Reception on Saturday morning was about the same, with a little less hum. Until 5 p.m. on Saturday afternoon volume was too weak to be readable, At 5 p.m. strength was R8, increasing to R7 by 6 p.m. The last half-hour was devoted to dance music for the ladies of the Antipodes. Mr. HE. Startz, the announcer, stated that he would be absent from PCJ till the end of March, as he was going for a trip to pain, Zeesen, Germany, 31.88 metres.-This is the best station received here at the pregent time. Tuesday from 6 a.m., orchestral selections at R9; Wednesday, -9 from 6 a.m., with a very fine choir; Thursday, R9, orchestra, commencing at 6.15 a.m.; Friday, R8-9 choir from 6 till 6.30 a.m.; Saturday, no sign till 6.30 a.m., when their programme commenced with a piano solo, received at R8-9. Not only is the volume good, but reception is near perfect in all ways. 7L0O, Nairobi, 31 metres.-This station appears to be approaching the season when it will not be audible. Early in the week signals were very weak, while

on Friday and Saturday they were not audible. . VK2MBE, Sydney, 28.5 metres, is to be heard testing with G@BX nearly every morning and evening at good strength. On Friday morning records were transmitted which GBX rebroadcast, being received back again in Australia quite clearly, so 2ME reported. "Hullo, Discovery," was called between items. After signing off with GBX, Sydney said they were going to play two more records for the "Discovery," GBX, England, 27.5 metres (about) testing with 2MW, Sydney. KZRM, Manila, 24.4 and 48.8 metres. -This station has gone off with the change of frequency. 58W, Chelmsford, England, 25.53 metres.-Volume is increasing now when 5SW opens at 7 a.m., but gushinéss as a rule spoils readability. Saturday morning, the best of the week, volume at 7 a.m. was R7. After Big Ben, it was announced that the third talk on careers for boys and girls would be on aviation by Major ? «The talk was 100 per cent. readable. KDKA, Pittsburgh, 25.4 metres, was reached. Volume was R8 by 5 p.m. No sign of them was heard on Saturday afternoon. W6EXN, Oakland, California, 23.85 metres.-Sunday afternoon very weak. Tuesday at 7.45 p.m. R4 with noisy background, Friday R8 at 7.80 p.m. with plenty of noise, signing off at’ 8.2 p.m. after giving the weather forecast. WOO, America, 23.1 metres (about).This new station has been heard each evening during the past week between 7.30 and 8 p.m, reading for GZGN (Olympic) and carrying out word tests, viz., "Write down." Volume is as a rule about R7-8, but signals are seldom clear enough to hear all that ig said. G2AA, England, 23.4 metres (about) .- This is another station heard calling the Olympie and conducting word tests. I heard G2ZAA on Tuesday at 7.45 p.m., R7, and again on Friday morning at 5.30 a.m. Readability was poor each time. The latest Call Book gives G2ZAA as Radio Communication Co., Ltd., Slough, Buckinghamshire. WOO could not be found in the same book. W2XAD, Schnectady, 19.5 metres — R2-3 on Sunday and Saturday afternoons was the best I could manage. PLE, Java, 15.74 metres, were heard with records on Friday and Saturday evenings. Volume and quality was excellent. DGW, Germany, 14.83 metres, were R7 with reading at 6 a.m. on Monday morning. Unidentified Stations. ‘ (THE list of stations under this heading is steadily growing. 35.5 metres (about) on Sunday at 7.35 p.m., R5, word test, and on Saturday 11.30 p.m., R8, with music. 46 metres (about).-First heard at 7 p.m, on Saturday with records at R7. Closed just after 7 p.m. for one hour. Started promptly again at 8 p.m. with more records. A, call was given several

times in a good English . voice, The last letter appeared to be G and I think he said Canada, At 8,10 pm. I heard "Closing down til]. Hastern Standard Time." Volume was about R7 all through, but talk was mushy. — 34.5 metrés 8 Date, an American voice, but not read able. 33.4 metres (about).-Saturday, 7.25 p.m., foreign talk at Rb. Closed down at 7.80 p.m, * 31.5 metres (about) Nearly every morning at 6 a.m. a foreigner has been heard talking at R7-8. Volume and clare ity has been very good. The language, I think, is German. 31.4 metres (about).-An American was tuned in about midnight, Saturday, at R45. Records were being transmit ted. "Constaninople" was heard about 12.15 am. The call was not heard, a morse station spoiling réception. 24.4 metres (about).-Thursday, 6 a.m., foreign talk at R8, with rapid fade, and again at 10 p.m, the same day.