RADIO NOTES

Rotorua Morning Post, Volume 2, Issue 251, 14 June 1932, Page 6

RADIO NOTES

"KATHODE."

By

Conditions during the past week have been good on the broadcast band. Excellent daylight receptio'n was experienced from the four YA stations, and several of the B class stations were heard to advantage. KFI, Los Angeles arrived most evenings with comfortable volume, and should be receivable on the average four and five valve sets. Static was fairly plentiful over the week-end though not enough to spoil reception. * * * Under normal conditions the howling valve type of interference has almost disappeared, but appears in an aggravated form as soon as items of particular interest are broadcast. From ten p.m. on Saturday evening until one a.m. Sunday morning, the air was cluttered with all types of oscillating receivers. At times, reception of 2FC and 2BL was almost impossible on account of hetrodyne interference, and one is led to believe that pirating with ancient receivers must have been rife. * * * Electro-magnetic, or radio waves, are received by two different paths, namely, the earth wave and the sky wave. The former is by far the most reliable and ' the coverage areas of broadcast stations are ealculated from the intensity of the ground wave. The sky wave will. cover great dis•tances, but is unreliable and is subject to fading and distortion. The coverage area of the ground wave depends upon three main factors, namely,' wave-length, power and terrain. A five-kilowatt station transmitting on 400 metres, would probably push the ground -wave out over

a radius of ten to fifteen miles, whereas if the same station operated on 40 metres the ground wave would probably be attenuated after covering less than one mile. On 4000 metres the same station would have a good service area over a thirty or forty mile radius. Taking these facts into eonsideration, one will readily see that Rotorua will require a B class station if first-class service is to be given the license-holders. * * *

The local transmitters are busily engaged making schedules to cope with message-handling at the Winter Show. The arranging of such schedules calls for an enormous amount of preliminary work and it will be some days before a final radio network has been arranged. Every main centre in New Zealand must be linked up with Rotorua, and arrangements must be made to enable transmission to foreign countries at shortest notice. Conditions at the present time are not good for working DX, and all messages for Europe will most likely be relayed through Canada or the United States. The local amateurs are in touch with Australia every evening so messages for that country will be delivered at short notice, whereas'b. relay to England will take several hours.

The depth of modulation at 2YA has been greatly improved of late and "Kathode" would now place that station fourth on the list for best tonal quality. 3YA still employs the varying speed turntable, which makes recorded music unpleasant to listen to. It is high time this station was supplied with up-to-date equipment. * * * Sunday night's band concerts from 2YA are usually a musical treat, and one wonders why some of the artists heard at them are not employed more often at the studio. Mr. Dan Foley, in particular, receives tremendous applause, which is an indication of his popularity, yet he is rarely heard on a 2YA programme. * $ An excellent type of indoor aerial may be made by pasting tinfoil over the under-side of a table and taking a contact from"~there to the aerial terminal of a receiver.

No doubt great interest will be taken in the transmitters' stall at the Winter Show. A complete highpowered outfit will be on view and many interesting exhibits will be there for inspection. The portable receiving and transmitting set used by the Radio Emergency Corps will be employed to relay the messages to an outside station. Most of the equipment used is amateur-built and the high state of efficiency of these stations will be realised when a complete station is examined. ❖ * The ground connection on a receiver should be as short as possible. One frequently sees a connection made to a water pipe that wanders all over the house before making a contact with earth. Under such circumstances a buried plate near the receiver would be much more efficient. One should be careful never to unduly jar a radio valve. "Kathode." had a receiver from the country handed to hina for inspection a few days ago and several of the valves were damaged, evidently through being severely bumped. Special valves are procurable for rough work, but the usual type of battery valve is a fairly delicate piece of apparatus.