RADIO NOTES

Patea Mail, Volume L, 8 November 1929, Page 2

RADIO NOTES

PROA C CAbTIXQ DTFFCC ULTIBB. (Concluded.) By Audiotroii. . Last week the results of investigations carried out by tiie American Bureau of Standards were discussed, and two of the conclusions arrived at were recorded. These conclusions were seven in number, and the remaining five will now be given;— (3) Signal phase displacements of less than 1880 degrees between like records made at the same time on coil types of aerial in varying positions arc explained by direction moves. (1) There is an absence of proof of fluctuating signals caused by the changing heights of the hcaviside layer, although there is evidence of reflection of the indirect wave from a rising layer, inasmuch as the signal intensity in the coil aerial at a minimum position starts at zero in daylight anu gradually increases during sunset. (o) Considerable fading is caused by rotation of plane of polarisation of radiation reflected from the upper atmosphere, especially during sunset, an explanation demanded by the 180 degree out of phase relationship between records made at the same time with

oop aerials in maximum and minimum positions. (0) The fading records show reflections arriving by multiple paths, indicating a periodic type of fading- superimposed on the main intensity variations and yet 180 degrees out of phase ')M simultaneous records ’with loop aerials in maximum and minimum positions, and this observation throws a question .mark around the calculation of the effective height of the ionized layer by moans of the size of the angle of ,incidence.

(7) The rapid fluctuation of signals previously noted by the JBureau of Standards during the sunset hour was observed as a common phenomenon in the reception of signals from the two broadcasting stations included in these studies.

From these conclusions it will be seen chat the problem of fading, while en-

gaging the attention of scientists, yet

remains the biggest hurdle yet to overcome in' long distance radio broadcasting. The * use of beam transmitters considerably increases- the strength of signals in a restricted path, but could not be applied to a broadcasting station serving a wide area. The only solution appears to be a> compromise—the use of really powerful transmitters, employing 100 kilowatts, and more. It would bo a good thing for listeners in New Zealand if the Radio Broadcasting Co. converted the Auckland, Christchurch, and Dunedin stations into 5000 watt stations (equal to 2YA). This would ensure-full loud speaker service to probably all parts of the country and of such strength so that static interference could be discounted. At present on a Wednesday night the service in many country places is extremely poor, and if interference is bad the listener is forced to shut down until some of the powerful Australian stations are receivable.

GENEKAL NOTES. The power ringer used in the local telephone exchange is a source of interference to adjacent radio receivers. This is particularly; noticeable with sets operated from the electric light supply mains.

Electric sets situated in the vicinity iif electric motors, battery charging stations, or electric high tension transformers are liable to reproduce many of the interfering noises generated.

Station KDKA, Pittsburg, TJ.S.A., was heard at speaker strength on Tuesday afternoon on a short wave receiver.

The relay of the Melbourne Cup was not well received in Patea from 2FA. Using a short wave receiver a local amateur reports reepiying HLO, Melbourne, at good strength on Tuesday afternoon and hearing the broadcast of the race excellently.

Station WGY, New York, is maintaining a fortnightly schedule for the benefit of Commander Byrd and his crew at the Bay of Whales. The transmissions are best received on the 32 metre wp/vc. and the next broadcast takes place on Sunday, November 17, from 3.30 p.m. to 5.30 p.m.