RADIO NOTES

Waipa Post, Volume 48, Issue 3468, 19 May 1934, Page 4

RADIO NOTES

(By L.W.S.).

AERIALS. The single wire horizontal antenna will give good results in almost every installation and for this reason has remained the favourite on receiver installations since the early days in radio. In a few special cases it may be replaced with a different type and the reception improved but these cases at',e the exception rather than the rule. Horizontal length does not add appreciably to strength of reception from an aerial. On the other hand, height is always advantageous. Service—as thought of in the radio trade is usually defined in terms of wire, tubes, and spare parts, but as far as the average salesman is concerned, it is something that has to do with the attending of indisposed receivers and hardly within his realm of activity.

is one thing to be said in favour of radio, even if you do have to listen to some of those bad sopranos you don’t have to look at them as well. An accumulation of dust on a valve-holder or between the legs of a valve will often give rise to a high resistance and leakage and cause intermittent “ frying noises.”

The aerial lead-in should in all cases be part of the aerial itself; meaning that the aerial wire stretched between the two supporting masts is continued directly down from one end to connect to the receiving set. It is not advisable nor, necessary to cut the wire and then connect the lead-in to the aerial. Unsatisfactory results from a set are often due to a faulty earth connection. When using a buried plate or tube, the joint where the wire is attached to should be inspected frequently, as corrosion is very likely to occur at that point. When a valve has to be inserted or removed from its socket, it should be gripped by the base portion, never by the glass bulb. In some cases, bad handling on the part of the user results in the two portions of the valve being forced in such an manner that the glass part becomes loose. To repair a loose bulb ordinary transparent liquid glue may be used, allowing sufficient time for the bulb and base to set before handling. Static oi- atmospheric disturbances arc due to uncontrollable atmospheric electrical disturbances, which affect any and every radio receiver on any wave length that it may be tuned to at any particular time. This disturbance manifests itself in a variable noise, having at different times very characteristic tones. Static is more intense during the summer months than during the winter months, because of the great humidity and occurrence of thunder storms during this period. It is especially strong, even in the winter time, just before a severe storm. Loud speakers vary in their tone reproducing qualities. Some are more faithful in their reproduction of the low notes, others in the reproduction of the higher tones. Loose diaphragms and other parts .may also cause distortion.

Many of the noises heard in the loud speaker of a radio receiver are not only due to the defects in the set but also to electrical disturbances coming from outside sources. A good test for the location of these disturbances is to disconnect the aerial wire entirely from the receiver. If the noises diminish or disappear entirely, one may be sure that their source is external to the receiver.

Household electrical appliances such as door bells, sewing machine motors, vacuum cleaners, flat irons, washing machines, violet-ray outfits, heating apparatus and the electric light switching systems contribute greatly to radio interference. Faulty power transformers and leaky insulators on power lines also cause a great deal of interference to the broadcast listener.

There are some rumours that television has been perfected by some organisations, to a stage where it is ready for release and which will be generally accepted as a form of entertainment, but apart from these rumours there is no other evidence that television is much nearer being a form of entertainment. Several lai’ge manufacturers have a department with research engineers devoting their entire attention to perfecting television, but they all state that- progress is very slow and they are not hopeful of early success.