Round the World on Short Wave

Radio Record, Volume III, Issue 33, 28 February 1930, Page 40

Round the World on Short Wave

An Unknown American. ME- ‘ MORRISON (Wellington) reports hearing an American station on about 90 metres several times recently from 7 p.m. till about 830 p.m. Usually all that is heard is "Hullo 118. Call radio." Various numbers are called.up at intervals. The longest call heard .was, "Hullo, 116. You've had an accident. Do you want the waggon? If so, we will send on at once." Mr. Morrison would like to know -if any: reader can throw any light‘ on this mysterious stranger. ‘More Short-Waves from’ Holland. HE Dutch Government short-wave plant at Kootwijk will soon be augmented by the addition of three new transmitters equipped for B.W. and radio telephony, which are now under construction. These will use the call-signs PCO, PCS and PDM. Their wavelengths will be 15.686, 16.60 and 16.182 metres .respectively. An Italian Short-Wave. ORK on the Rome_ short-wave ’ -broadeasting station is progresstng rapidly. The transmitter, installed: at Cecchignoletta, at a short distance from the Italian capital, will be capable of radiating a power of some 12 kilowatts in the aerial. It will relay the advertised Rome programmes for the benefit of Italians resident in African and other colonies. Although the wavelengths have not been made known officially, it is stated that 25 mietres and 80 metres may be the ones adopted. A. Two-Metre Claim. FT RAN SMISSION tests with waves of '‘% three metres are referred to in the German amateur periodical, "CQ," which states that success on these high frequencies has been attained by Dr. Karl Stoye by means-of a special arrangement of superyegeneration circuits. Transmitters and receivers functioning very efficiently on the 3-3.40 metre waveband are reported to be constructed with ordinary commercial] apparatus, while a 2-metre wave is said to be attainable with the use of special valves.’ Reeeption during Week ending February 22, 1930. RA9%, Siberia, 70 metres, was tuned in on Monday morning at 6 a.m. in time to hear a special transmission announced for Western Hurope. "The opening announcement was made in Russian by a man and in English by '2 woman-the latter was heard frequently during the evening’s programme, One musical item was given, the woman then talked for about fifiéen minutes on the reported religious persecution in Russia. She said that these reports were a "crusade against the Soviet Union." Later she said they "were credited with doing things they had never dreamed of. ‘A fine musical programme followed from the "radio studio" (so the announcer said). Reception was excellent except for the usual _ trouble--static. W9IXF, Chicago, 49.83 metres.-This station has been closing down at 7 p.m. each evening during the past week, one hour earlier than usual. Reception has been fair, but not so strong as a few weeks ago. W2XAF, Schenectady, 31.4 metres, was on the air at midnight on Tuesday,

testing with 2MH, Sydney. Volume was R4 and very gushy. Reception was also poor in Australia. 2XA¥F was well received on’ Saturday afternoon, being R9 by 4 p.m. PCJ, Holland, 1.4 metres.-On Friday and Sattrday this Dutch station came in at R9 from 6 a.m. and continued at good strength throughout each transmission Saturday afternoon, signal strength was R2 at 4 p.m., increasing to R8 by 5.80 p.m. Reception was ‘spoilt by static. Zeesen, Germany, 31.38 metres, has again been the "star" station. The published transmitting hours are not observed. On Tuesday a band was heard till 6 a.m., after which the station was silent. Wednesday, male choirs from 6.20 a.m. Thursday, organ recital from 6.30 a.m. Friday, choir from 6.30, a.m. and on Saturday from 6 am. American jazz items. VK2ME, Sydney, 28.5 metres, has been testing with London nearly every morning and evening. On ‘Tuesday evening they were taken, with W2XAF, Schenectady. , -GBX, England, 27.5 metres (about). -Testing on duplex with Sydney. KZRM, Manila; Wavelengths, vari-ous.--Radio Manila was on its old 26metre wavelength on Wednesday evening. Reception was spoilt by static. On Thursday, Friday, and Saturday they were on 488 and about 24. metres, A wedding service was broadeast fro.1 KZRM on Saturday evening from about 10.50 p.m. Readability was poor-about 50 per cent. at R4-5. G5SW, England, 25.53 metres.-Was quite good on Thursday morning, when a talk on "Canning Industry in Great Britain" was 100 per cent. readable from 7 a.m. Rapid fading spoilt reception.on other mornings. KDKA, Pittsburgh, 25.4 metres.-On Sunday from 4 p.m. a programme for the Byrd Expedition was _ broadcast from the William Penn Hotel was received at R&. Reception was poor on Saturday. W6XN, California, 23.35 metres.Was tuned in at 6.30 p.m. on Friday, when the National Concert Orchestra were excellent at R9 till 7 pm. From then till 8 p.m. the Musical Musketeers were heard. On Sunday volume was R7, at its best about 4.80 p.m. W28AD, Schenectaday, 19.5 metres. -Was very weak on both Sunday and Saturday. PCK, Holland, 16.3 metres, and PLE, Java, 15.74 metres-Were on duplex telephony at good strength on Friday evening, Unidentified Stations. THE stranger on 41.6 metres (about) has been heard each morning, strength about R38 at 6 a.m. and always alk, . Another German, a fraction higher in wavelength than Zeesen has been

heard several times between 6 a.m. and 6.30 a.m. at about R6. Talk only has been heard. L

Technical Tips

A einen Rejuvenating Accumulator Plates. A COMMON method of rejuvenating the plates ‘of not too badly sulphated cells is to send them for an. extra long charge at a slightly lower charging rate than normal. This is greatly facilitated in its function of reducing the accumulated sulphate if some sodium sulphate (commonly known as Glauber’s Salt) is added to the electrolyte. A Useful Contaet Stud. HE two small spring plungers found in any ordinary electric lamp-hold-er are. useful accessories for many wireless purposes. They can with adyantage be incorporated in many home constructed components as sliding contacts, ensuring a smooth motion — together with a positive contact, and are to be preferred to the fiexible leads which are often connected to the spindles of switch arms, etc. Locking Condenser Dials. A VARIABLE condenser dial which is not securely fixed on its spindle is a source of great annoyance to the operator, because the readings noted from it cannot be relied upon. The dial is often locked in position with a small grub screw, and a trouble sometimes encountered by the constructor is that he has no screwdriver with a narrow enough blade to enter the hole in the knob and drive the screw well home. The use of too large a screwdriver under these circumstances will damage the knob, and may even split it if it is of the moulded type. It is quite worth while to keep as part of the wireless workshop equipment one of the small screwdrivers which are used by watchmakers. These are made entirely of metal, with a hollow handle to hold blades of various sizes. Removing Scratches. HEP seratches that penetrate through the finish on wooden radio eabinets may be rendered invisible if the correct procedure is followed. First, stain the wood in the serateh with a matching stain. Allow the stain: to dry for about 24 hours, and then coat the scratch carefully with a first-class grade of furniture varnish. After the varnish has been allowed to dry -thoroughly, take an old razor blade and scrape off any excess varnish. Apply three or four applications of the varnish in this manner. Finally you will

find that. the varnish coats have buili up until they dre flush with the sur face. of the original finish. The en; va tire Surface can then be rubbed with a mixture of powderéd pumice { stone and oil. Testing for Hum. "THE critical point in any all-electrie receiver-the point where hum is most likely to be produced-is the detector circuit. Consequently wheneyer an A.C. receiver begins to develop a steady hum. the detector valve should be investigated. In many types of cixcuits, when the set is first turned on, 2 hum immediately develops and then dies out as the detector valve heats to operating temperature. As the valve becomes older the time required for it to reach operating temperature becomes longer and longex. and in many cases the hum does nd, die out. It is a good idea, therefore, to have a good, new spare detector valve on hand. Then when the set develops 2 hum, substituting the spare ‘falve will give a definite indication as to whether the detector -valve is to blame. If the hum continues with the spare, detector valve in place some other part of the circuit is at fault. In an electric set the hum is not always of the same intensity. Some nights it seems to be worse than others. ‘This variation frequently is caused by changes in the line voltage or in line operating conditions. The hum is much less when the gramophone pick-up is used. This is because the pick-up does not produce hum, and when it is cut into the circuit detector valve hum is eliminated. .