THE WIRELESS WORLD.

Otago Daily Times, Issue 19475, 9 May 1925, Page 18

THE WIRELESS WORLD.

NEWS AND NOTES.

By Magna Vox. [ltems of nows, comment, suggestions, etc., will be welcomed by "Mugim Vox.” Jn order to ensure publication correspondents are advised that letters must be received in the office not later than, Tuesday evening.] STATION 4YA. LONG DISTANCE REPORTS. Radio 4YA, the local broadcasting station, has been making astounding records since being back “ on the air.” The latest record is announced in a letter from Chicago, U.S.A., in which a listener claims to have heard 4YA at 6.25 p.m., Chicago time. Mr F. J. O’Neill states that the item heard by this listener was probably one transmitted during a test. If the claim is authenticated 4YA may claim to be the first New Zealand broadcasting station to bo hoard in America. Another letter from Chicago states that at 7 a.m., Chicago time, a song, “Silver Threads Among Gold,” and a piano solo were heard from a New Zealand: station,, but the call-sign appears to be in doubt. Programmes broadcasted by 4YA have been received complete in .Australia, where some listeners, apparently, look upon 4YA as a regular source of entertainment, from Woonona, N.S.W., a letter was received stating that 4YA is picked up well on a receiver using one UVII9 tube for the detector. with no amplification; the aerial being a single wire 110- feet Long and 35 feet high. A listener in Temora, .N.S.W., using a Reinartz and one step of amplification, tells the same story. In South Australia (Farrell’s Plat) 4YA has been heard at a distance of 60 feet from the loud-speaker on a set using one stage of radio-frequency, a detector, and two stages of audio-frequency. Rarotonga is the origin of another .reception report; the operator Of the wireloss station there receiving 4YA on one De Forrest Dl2 valve. Reports on the reception of this station within' New Zealand are, of .course, numerous, one listener, in the Bay of Plenty, stating that concerts from 4YA are received with- twice the volume of IYA, Auckland. Altogether, Mr O'Neill and the operator of the station have a creditable record on which to congratulate themselves. The programmes from this station were recently placed in the hands of a paid programme organiser, and the items transmitted are expected to be second to none in the dominion. Radio 4YA uses the master-oscillator system, this having been found the most efficient system after extensive trials. A small tube is utilised to generate the BLF.. and this is amplified and put into the aerial From the microphone the current goes to the modulation transformer, which excites the grid of a five-watt speech amplifier The current from this goes to the modulating tube, which in turn modulates the wave of the oscillator tube. From the oscillator circuit the oscillations are amplified by four 250-watt tubes, which put about four amps, into the aerial on 370 metres.

SHORT-WAVE DISCOVERIES. Tho latest achievement by amateur wireless enthusiasts —that of the new discoveries regarding tho peculiar carrying properties of certain short wavo-lengths during darkness and daylight—opens up a now and extensive field for research, a field that will probably have far-reaching effects on commercial wireless communication of the present day. The discovery may be briefly summarised in the statement that it has now been conclusively demonstrated that the shorter waves—i.e., waves of about 20 metres, offer tremendously increased carrying powers during the hours of daylight; but that they are practically useless for communication during the hours of darkness. Waves of about 40 metres, on the other hand, are exceedingly efficient for night communication, but are of little or up use for covering long diistances in daylight. These results have been put to tho p'oof by certain amateurs in the United States, who claim that results on 20 metres in daylight actually surpass results obtained with larger waves at night. In proof of this direct daylight communication is now being maintained right across the continent of 'America in daylight by amateurs in California and Oonneotc-ut, using a power of one kilowatt. Mr C. D. Maolurcan, of 2CM, Sydney, also lias put this discovery to the test, obtaining results far beyond expectations when ho actually worked 20D, Mt Simmonds, near London, in daylight on a wnvo-length of about 20 metros. Tho theory dealing with these amazing results has not yet been published; but experimenters in America who are investigating this subject declare that the experiments wore made in confirmation of a theory already conceived, which made it posiblo to prophesy that 20 metres was a wave-length excollonty suited for work in daylight, that 40 metres might do the same thing, and that the two waves would not work the same at sunset and sunrise. Mr R. Slade, 4AG, it is understood, has been carrying out extensive experiments with the short waves during tho last week, and the results should bo very interesting

VISIT OF AMERICAN FLEET. In connection with the visit to Australian and Now Zealand waters of the United States Navy short wave tests will be arranged by tho warship Seattle operating under the call-sign NRRL with radio amateurs in the two countries. The transmitter aboard the Seattle will employ a power of one kilowatt in the aerial, and will be operated by the traffic manager of the American Radio Relay League, Mr f. H. Schholl, on wave-lengths of 27.2 or 54.4 ‘ metres. Mr Schnell is installing his own transmitter and receiver also, which will work on 20, 40, and 80 metres. No definite programme is being arranged, but during- the hours of daylight NRRL will listen in on 20 and 40 metres; and ar night will sweep the ether over a waveband of 75 to 125 metres. The wavelength of 54.4 metres will mostly be .is'd for transmitting after dark, 27.2, 20. and 40-metre wave-lengths being employed for daylight work. All amateurs are asked to furnish reports on the signals and communications to the Director, U.S. Naval Research Laboratory, Bellevue, D.C. It is important that a log extract be sent on every occasion (,n which NRRL is heard.

DOTS AND DASHES. _ The annual general meeting of the Wellington Amateur Radio Society was to have boon held recently, but as only six members attended it was adjourned. Those pre sent discussed the recent conference of representatives of wireless organisations, and approved the actions of the Wellington delegates. It would appear from this that Dunedin is not the only city where there is a marked apathy shown in regard to attendance at annual meetings; but ’t is somewhat surprising that this should oe the case in Wellington, where it might be expected that _as the two conferences have been held in that centre amateurs would be more enthusiastic. Advice was received recently that the Postmaster-General had agreed to a postal ballot being taken for tho selection of a listeners’ representative on the Broadcasting Board. A candidate has to deposit £5 and forfeit it if he does not receive 10 per oent. of tho total votes polled. Up to the present no official advice of this poll has been received locally.