RADIO NOTES

Rotorua Morning Post, Volume 2, Issue 326, 13 September 1932, Page 7

RADIO NOTES

"Kathode.")

(Notes hy

The past week has ibeen an excellent one, both for local and overseas reoeption. The YA stations have been arriving with plenty of volume and a marked absence of fading, though periodic distortion has been noticeable. 4YA has returned to its original wavelength and a noticeable increase in volume has marked the change. 1YA has substantially increased its wavelength and is now received clear of hetrodyne interference. Though too early to f orm a definite opinion, it seems that 1YA is being received with greated volume on the new wavelength', with less fading and distortion. Of courge, improved conditions will account for more than a little, though daylight reception appears to be decidedly better. KFI, Los Angeles, has been coming over well, and other American * stations heard were KHJ Los Angeles, KSL Salt Lake City, KPO San Francisco and KOMO Seattle. The Australian stations are strong just now and, a number of the small B class stations have plenty of punch. Condenser types of loud speakers and microphones have been developed almost to perfection, and before long electrostatic pick-ups will reeeive the attention of eiigineers. It is rather surprising that the condenser principle has not been more widely used in th'e case of gramophone pick-ups,, as the output would he extraordinarily true in the musical sense. The condenser microphone, though not sensitive, possesses the. great advantage of dojng equal justice to all the notes in the musical range, from high to low. It is free from natural resonance and therefore has no tendency to emphasise certain notes. Ilts operation depends upon the fact that th'e capacity of any condenser changes if the distance between the plates is altered. Accordingly, if two plates are used, one being made flexible so that it can move relatively to a fixed one under the influence of app'lied sound waves, we have a condenser, altering in capacity for every sound wave impressed upon it. The two plates are polarised and the capacity variations set up minute voltage variations and these are amplified in the ordinary way. While the frequeneies found off a modern gramophone record are far from perfect, added imperfections result from the use of the modern types of pick-ups, even though 'efforts to balance them out have been made. A condenser type pick-up would make a vast improvement to all lcinds of recorded music and no doubt before very long developments will he made along that line. One nears and rt«,^s a lot about B class stations and advertising over the air. Advertising, if well chosen, does not detract from the qualtiy of a programme any more than a list of books at the end of a novel would detract from the interest of the story. Some of the American stations and, in fact, the chi'ef stations there, advertise in different form, but in such' a manner, it is not in the least offensive and yet carries a big advertising value. For instance, when listening to a programme from KGO, one might bear this familiar announcement: "Six o'clock, B-u-l-o-v-a, Bulova watch time." That is all and the transmission carries on with the usual concert programme. Listen to KFI and you will not hear any more than that. Broadcasting House, London, is the most up-to-date building for radio transmission in the world. Statistics are notoriously dry reading, but nevertheless the following canght "Kath'ode's" eye. The building contains 2,630,000 brieks; there are 1250 stairs, 800 doors, 7500 panes of glass, and no fewer than 130 sub-contractors were involved. The cost of the building round about £750,000. The studios are twenty-two in all, and are grouped in a central tower, surrounded by 'air, so that they are completely insulated from all external noise. No steel was used in the erection of this tower, as the metal would act as a conductor of sound. The log for the past week is: — Australia, 2BL, 2FC, 4QG, 3AR, 3LO, 2NC, 5CL, 3UZ, 2GB, 2UE, 2KY and 2UW. America. KFI, KHT, KSL, KPO, KOMQ and KGO.