Round the World on Short Wave

Radio Record, Volume II, Issue 28, 25 January 1929, Page 32

Round the World on Short Wave

Mr. A. P. Morrison (Brooklyn) writes :- Shortwave reception this last week has been very good with me. I have cleared: up the mystery station, "JCE, Paris." This station was heard after midnight on Tuesday, January 15. He was operating on 26 metres, and his call-sign was heard three times. It is: FL, Radio-Electrique, Hausmann, Paris. Two other new stations have been heard. PLG, Java, when heard last night was operating on 17 metres by the readings of my condensers, and they stated that PLG was a new transmitter, and last night was their first transmission. I might state it was said from PLG that Java has five Ls.w. ‘transmitters now, and that all callsigns have changed. These calls were mentioned: PLE, PLF, PLG, PLR, and PLI. I have written to Jaya in regard to their changed call-signs and wavrelengths. 2ME, Sydney (Australia), call-sign is now PK2ME. My log for the week is as follows: -- Friday, January 11. 6.30 a.m.: TLO, Nairobi, heard giring news reports, and afterwards music; R6. 7.5 am.: 5SW was R7 fading; spoilt reception. 9 pm, W2XG, Rocky Point (America), with his word-test (write down transformer, ete.), Its. 9.30 p.m., RFM, Russia, was at good volume: R8&. More talk, then music, as usual. 11 p.m. : PCLL, Holland, broadcasting music was R9, but distorted. 11.15 p.m.: ANE, Java, 15.74 metres. with music, volume was tremendous and modulation was perfect (1 might say, R19). Afterwards both stations carried out duplex telephony. Saturday, January 12. No SW stations in the morning. 3.30 p.m.: W2XG, Rocky Point, word test; strength, R7; W2XAD was not heard, or KDKA. W2XAD LI have not heard since he changed his wavelength down to 19 metres. 9 pm.: RFM, Russia was at goud strength: R8. I did not listen again on the SW band till 12 p.m., listening to 2YA and the boxing from YBL. Sydney. 12 p.m.: 52 metre stations as reported before. Musical items; strength R6: no ecall-sign heard. 12.18 p.m.: Station on 41 metres. both musical and yocal items heard; Ri. Call-sign heard, PRN, but did not get location ; foreign. 1lam.: PELL. ANE, and ANII were all heard on duplex telephony with one another, the two former stations at R8 and ANH, R7.

Sunday, January 13. Between 11 a.m. and 12 p.m,, 2AX, Palmerston North, on 82 metres, testing R8. 3.30 p.m.: W2XAF, B4, dance music, but inereused to RS by 5 p.m. 4 p.m.: SKDKA very weak, R3 to 4; did not trouble him much in afternoon, heard him again at 6 p.m. Special programme to Byrd expedition was heard back on 25 metres and 63 metres. His strength on 63 metres was RS, while on 25 metres he was only about R6. This programme coneluded at 8.15 p.m. New Zealand time, quite an enjoyable programme. Monday, January 14, 6.45 a.m.: 8L0, Melbourne, was on the air with their usual Monday morning programme. Strength was Rs, but fading slightly. RFM was heard in the evening, R7. Also two New Zealand amateurs, ZL2ZAR working ZL2GA. Tuesday, January 15. 6.30 a.m.: 7LO, Nairobi, very weak; R4. OSW was not heard by me. 9 p.m.: JHBB, Japan, on 32 metres. Modulation was quite good for the old Jap for once; R6. 9.30 p.m.: W2XAG, as usual, word test; R7. 10 pm.: RFM, Russia, with some good music; R8. 12.5 am.: FL (2CI, Paris) was heard on 21 metres, absolutely per- fect modulation and strength R9. No music was heard, all speech. My reason for so late a sitting this night was to test the strength of 5SW. He was heard at 12.45 a.m., two faint itenis first heard, and I must say his night receptions with us are better than the morning. I was surprised at the volume; strength was Rs. Before closing down for the night a station on 15 metres was heard at R6. A man talking in foreign language, but could not make out the call. Wednesday, January 16. 7 a.m.: 5SW with a vocal item; RG. 8.20: ZL2ZGH, Wanganui, 80 metres, testing; R7, 9.15: JHBB, Japan, operating on 60 metres. Even better than Tuesday night; mostly talk. Strength Rs. 11 p.m.: PK2ME, testing with PLG, Java, duplex telephony; RS. A slight fade. 11.5 pm.: PLG, Java, as above. PLG performed a new one to me. At one part of their transmission the announcer stated that he would connect a telephone line from the studio for someone to talk to PR2MBH, and the test was quite good at this part of the transmission. 2ME could distinctly be heard at PLG end. Thursday, January 17. 9 p.m.: JHBB, 37 metres. When first heard a little girl was singing. but modulation and strength was not too good, so did not trouble him much. About RG. To-night I have’ taken my entertainment from RFM, Mussia. They have had a full. night’s programme and are still going. Some wonderful music and ‘singing heard and strength is everything you could wish for; R9.

Short Wave Peculiarities

Helpful Hints WHEN one gets down on the really short waves, such as the 20 to 35-metre band, usually a number of things strike him as being perplexingly different from the conditions he is familiar with on longer waves, and ulthough he may get used to them, there is always a feeling that the set would be pleasanter to work if it would behave in a more rational fashion. . Sometimes it is possible to remove or reduce these little peculiarities by various dodges, such as one learns by experience, and the disconnected notes which follow are intended to help in getting rid of two of the most tiresome ones. They are based on experiences with sets of the general type likely to be in use among readers, and it may be taken that the remedies suxgested are of a universal nature and will suit practically any case. Moving "Flat Spots." IRST of all we have the rather curious phenomenon of "flat spots" on the tuning range of the set. These are patches-sometimes only a few degrees wide, at which a great deal more reaction has to be used to make the set oscillate (in extreme cases it miay refuse to oscillate at all), and on either side of which reaction is quite normal again. It may be found that there are two or three of these patches on the tuning range of a given coil, and they can be a great nuisauce, in ways which need not be described since they will be painfully familiar to most readers who have tried the short waves. The usual remedy recommended is to place a small fixed condenser in the aerial lead, and although this works (at any rate, it shifts the flat spot somewhere else), it is rather a nuisance to be obliged to transfer the aerial] leud to a fresh terminal on the set, and then shift it back when the flat spot is encountered once more iu its new position. Besides the condenser, if small enough to do its job, usually reduces signal strength a little. A better cure in most cases is to weaken the coupling of the aerial to the tuned circuit. Where a separate aerial coil is used this is fairly simple, and it generally pays to- provide some scheme for swinging this coil away from the secondary. For example,

where plug-in coils are employed, you can use only a single screw for fixing the aerial coil socket, so that you can afterwards adjust it to various angles. Flat spots are generally quite easy to move in this way. . Cures for "Threshold Howl." HEN the aerial is connected straight to the tapping on the tuned grid coil matters are a bit more difficult, and probably the ‘best solution is a tapping clip which can be. quickly moved from turn to turn to give various degrees of coupling. The only serious drawback ‘to this method Is that it causes considerable changes of

wave-length, so that you must be pre- f pared to re-tune fairly frequently to © find your station again. Then again there is that annoying squawk or how] heard with some sets as they go into oscillation, commonly called "threshold howl," since it stops once oscillation has started properly. It is a rather mysterious complaint; but the main causes appear to be these (the remedies. being fairly obvious where they are not given): (1) Aerial coupling too tight. (2) Reaction winding too big, or possessing too much capacitative rather than magnetic coupling to the grid coil. . (8) Detector valve of too high ang impedance, or unsuitably supplied wit B. and A.. or unsuitably biased as to~ grid (try connecting lower end of grid leak to slider of a potentiometer). (4) L.V. side unstable (reverse G.B. and G, leads to transformer) or being upset by intruding stray H.I’. currents (use better H.F. choke, by-pass transformer primary with .0005-mfd. condenser, and space out the parts a little more widely).