WIRELESS NOTES

Nelson Evening Mail, Volume LXIV, 10 January 1931, Page 4

WIRELESS NOTES

Do’s and Dont’s. If static is bad on the wave length tuned into, don’t persevere with that station which is marred by static; it may make your head ache and cause your hair to suffer. Don’t try to tune in a short-wave station on a loud speaker; use the ’phones when tuning in on short-wave. Quietness is essential; and talking absolutely barred if you want best results.

Don’t forget that you can have overseas music with your breakfast if thus inclined.

Don’t stand over an open receiver smoking cigarettes; any ash that falls into the inside has eventually got to be taken out; the less that goes in the less to be taken out.

Don’t jump vigorously on the floor near the receiver; many children cause trouble through doing so. Don’t place the receiver near a cold current of air, or moisture. Don’t forget to keep dust away from the receiver.

Don’t bang the cover or lid down hard on the receiver; especially the combination type of electric, receiver. Don’t fool around the receiver with the current connected; or batteries connected up to receiver. Don’t start fiddling around with your receiver immediately after washing your hands; wait until your hands are thoroughly dry. Don’t forget to keep the accumulators supplied with distilled water. Don’t expect to get the same results with a £ receiver as someone else gets With a- £SO receiver. Materials cost money; and quality must be paid for; unless the vendor is a wealthy philanthropist. Don’t try to tune-in a short-wave receiver unless your arms are restful (use a soft cushion to rest the forearms on). Don’t use the tuners with dirty hands; hands should be clean so that complete control of the receiver is possible. Dry smooth hands are better than moist dirty ones; sticky fingers should be avoided when handling the tuning controls.

The Attractions of Portables. There is an increasing number of listeners who cannot be bothered with the erection and maintenance of an outdoor aerial and who are intrigued with the easy operation of a self-con-tained portable receiver, which is about as easy to operate as a gramophone. Moreover, it can, like the gramophone, be carried about from room to room wherever it may be required. As regards the efficiency and range of reception of a portable receiver (points upon which it was open to a good deal of criticism until comparatively recently) these have now been greatly improved and extended by the introduction of the scrccncd-grid high frequency amplifier, and with a portable model employing a couple of stages of scrccncd-grid 11. F., the need for an outdoor aerial is eliminated.

Orchard Pests Killed by Radio. Orchardists will be interested in a recent application of radio as an exterminator of insect pests in tho orchard. The system has proved both efficient and practicable, and hours have been allocated by the American broadcasting authorities for “spray broadcasting” in orchards.

A scries of aerial and earth wires is used, attached to a generator which furnishes 110,000 volt of high frequency electricity. The current travels from tho aerial, which is stretched above each tree, through the trunk to the earth wires below, and back to the generating machine, thus completing the circuit. Fruit growers and State inspectors Who have tested the system throughout report that the current kills insect eggs, scale, and other fruit parasites by “exploding” the cells and sterilising them. Insects flying, in the path of the current are also killed. The inventor of the system is the late Dr. B. N. Burgland, who is credited with extensive researches in radio and high-frequency electricity.

Loud-Speaker Hum. Low-frequency lium may be due to a Variety of causes, but there is one that is sometimes overlooked, though it is the simplest of all to remedy. Strangely enough, it will often appear for tho first time in a set that has recently been fitted with a mains-eliminator, probably because the valves then work more efficiently than when the plate voltage is drawn from a dry-cell battery. The particular hum in question is due to microphonic reaction between tlie loud-speaker and the valves. It can be cured simply by moving the loud-speaker sufficiently far away from the set to prevent the vibration of the diaphragm from affecting the valves through tlie intervening air.

License Must Be Purchased. A license must be taken out as soon as a radio set is installed. Some people are under the impression that they may borrow a receiver from a licensed dealer and keep it on trial for an indefinite period, but this belief should be corrected. According to Government regulations any prospective buyer is only allowed to keep the set in bis home on trial for a short period, and this clause applies only to a set being purchased from a licensed dealer.