OVER THE AERIAL.

Auckland Star, Volume LXX, Issue 140, 16 June 1939, Page 14

OVER THE AERIAL.

RADIO NOTES.

FROM FAR AND NEAR.

(By TUNE-IN.)

Commenting on the notification in the •'Gazette - ' of the dissolution of the New Zealand Federation of Radio Listeners. the Titnaru "Herald" says: "This body never actually advanced to the federation Mafje. One of the plank.was eeini-]K>litk-Hl action, and the club that sponsored it was captured by a hostile party."'

Kadio Paris may soon be the world's most powerful broadi-aetinji etiction. Tests have hegtni on a power of 4."i0 kilowatts —compared with SO kilowatts as at present —and Ibis may be increased to (>DO kilowatts and even uo to 9<H). A new station, which will broadcast on the same wavelength. 10.4S metres, as the old Kadio Talis, is being built at the little village of Allouis. near Bollurgee, Central France. The object of the extra power Is to permit broadcasts to places such as North Africa and Central Kuropc. .Moscow (500 kilowatts) i.s at present Kuropc'a most powerful st-ation.

"A.CV submits tlio following ■■ query to the radio writer of the Tiiiiaru "Herald": "Which is the better aerial for good reception. a braided 7/03W or a plain 7/O.'s(i wire '.'" That is a point on which experts differ. It appears that for ordinary reception no difference is discernible, lint must successful DXeivs u«e bare cop[ier. of tin , world's mi view use lmbraided copper enamelled to prevent corrosion by spray. Brni<le<l wire has the advantage of keep ing cleaner, but prnlnilily is a little les* wusttive to weak long distance signals. If a bare wire is used it i<< necessary to haul it down at fairly fre(pi<Mit intervals and to clean it of accumulations of soot or tarnish left by rain. Where this is inconvenient, braided wire seems to be called for.

The question concerning aerial wires serve* a* a reminder of how little attention the average net-owner pays to this important part of a radio installation. fn the. majority of cases a salesman installs an antenna, and it rtays put until it is blown down or is eaten through by corrosion or rust. It is amazing to see the thickness of the coating of μ-rime that an aerial will acquire in six months, particularly in area* adjacent to the railway. A ehfrie-up with a piece of emery cloth will improve long-distance reception just, an greatly <\n the application of a couple of buckets of water to the> '"earth" in drv weather.

More limn the customary grain of salt should be taken when rending annoiinceinents that television i« on tlio verge of becoming popular and inexpensive. Omitting, for the moment all questions of the huge cor<t of 'transmitting ajiparatus and the yet unsolved problem of programme material, thi* newest radio art is certain to prove expensive. The niont modest of receivers require l(i to 20 valves, very voltage, and an expensive power pat'k. to say nothing of a contly and fragile cathixl ray tube. In fnct. ii television receiver consists of two complete receiver«a, one for voice, and the othec, for image. The image portion of the outfit is exceedingly complex, and it has been found that on present systems simplification is impracticable without seriously impairing clarity of results.

While it i« difficult to assess the probable number of hours of service to bo expected from the valves of a receiver, it is safe to say that under normal condition*! they will function satisfactorily for at lea«t several years. The. actual period depends on the voltages applied to the valves, the types of valve**, and the electrical and mechanical shocks to which they aro subjected. IVually the first sign of approaching valve failure i* a graduul falling off in .sensitivity and volume. It is a simple matter to remove the valves and have them tented in a tube checker.