Short-Wave Notes

Radio Record, Volume II, Issue 45, 24 May 1929, Page 39

Short-Wave Notes

Duplex Telephony Tests -_--_--- ON May 8, at 8.45 p,m., a strong carrier was heard on approximately 52 metres, sending a tuning note, afterwards in slow Morse’ the call sign. of station On waiting a little while, the announcement was made as follows: ‘Hullo, ladies and gentlemen, this is WJC (or 3X1) testing." I left the set a little while, but on returning 3XL was off the air, It is an experimental station, and is located at Boundbrook, New Jersey, N.Y. His strength on the 8th was RZ to 8. Amateurs heard on Friday, May 38, were 2BO and 2AY, carrying out duplex telephony test on 80-metre band, both stations coming in well; in. fact the little test was well carried out, and I would like to hear some more of it next Wednesday. 2BO stated that K2ME and Java would be "jealous," or words to that effect. 2AX, Palmerston North: Wonderful strength, but modulation a little harsh at times, 2BE, Hastings: Strength R9, clear and steady-a transmitter to be proud of. It is surprising the strength some of these hams come in with at times, and makes one think they are using 30,000 watts instead of 30 or so. So carry on the good work, hams. Saturday, May 4: PC3, Holland, was heard on their afternoon programme, coming through at great strength. The latter part of same was special for Sydney radio show, which was in full swing on Saturday. The test with 2ME and W8XK I heard on May 8. Both sides of the conversation came through quite well, 2MD fading a little; this fade was_also noticeable with W8XK, so he stated. WSXK mentioned in his conversation that CJRX had been relaying 5SW, Chelmsford, and also that BSW was heard quite well in Pittsburg, some days being weaker than others. Duplex telephony has been heard on Saturday afternoons and Sunday mornings between Germany and South America, the German on 26 metres and the American on 31 metres. By the nature of the conversation heard, it seems a wireless duplex telephony service has opened up between these two countries, because many times different people at both ends have been heard to converse on private matters, and after such conyersations Germany was heard to give the time taken for the call to Amerjca. To quote on time given, Germany stated that it was four minutes 20 seconds, but 1 heard nothing in reference to the charg to be made for each call (probably £5). I am sure the German was DHC, Nauen, the shortwave station who carried out a epemapaied ----_

great many tests with VK2MBE a little time back, Our friend London calling has been heard a great many times lately on word tests, but so far I have not been lucky enough to get his correct call-sign; in fact, he never gives anything else but "Gondon ealling," or "This is London." A Useful Filter, GETTING away from the shortwaves, ~\" this may be of interest to experimenters in wireless circles: An Wastern radio concern has designed an interference filter for preventing noises from the power line from interfering with the operations of electric receivers or power supply devices. This filter may also be used to prevent radiation and interferenge from electric sewing machines and ‘a similar electric appliances.- . Two typés are available, on can be used with a maximum, voltage of 220 volts A.C,, or 400 volts D.C.; and the other designed for operation with 125 volts A.C. or 20 volts D.C. This filter consists of two 2m.f.d. in series with mid-pojnt, grounded as shown, the interference filter and circuit diagram of conr nections are i---~

I should like anyone who is trying out this as a filter to write me and tell me their results.