Glossary of Wireless Terms

Radio Record, Volume I, Issue 48, 15 June 1928, Page 14

Glossary of Wireless Terms

UNDER this heading we will.give regularly sections of the glossary . of wireless terms which is a prominent feature of the N.Z. Radio Listeners’ Guide. In that book, although set in the smallest type, it occupies some 13 pages, and is definitely in our opinion the most comprehensve and complete glossary on modern lines which has been made available in the Dominion. For the benefit of our readers the glossary will be reprinted in our columns.

"3" BATTERY.-The _ alternativ name for the high-tension (I.T.) battery, It is employed for applying an electrical potential to the plates (or anodes) of valyes. ‘The "B’ battery may comprise "dry" or "wet" cells (ac. ‘cumulator type). It comprises several groups of cells totalling 224 volts, or 45 volts in the case of "dry" batteries, waxed into cardboard enclosed blocks, and from 24 volts upwards in the case of "wet" batteries. Care must be exercised not to connect the "B" batteries to the filaments of valves, in place of the "A" batteries, as the valves would be irreparably damaged. BAKELITE-An insulating material presenting an appearance very similar to ebonite. Ilas very high heat-re-. sistant properties. The majority of. panels, dials, ete., in radio sets are madeof this material. BALLAST TUBE-A. special valve, usually gaseous, which is installed in B battery eliminators for the purpose of maintaining constant operation of the device irrespective of fluctuations of input ovr output. BANK WINDING.-A system of winding adopted so that adjacent turns either on each side or above or below shall not be at a materially different potential, The self-capacity of such a winding is kept at a minimum thereby. BASKET COIL.-A coil of high efficiency and simply construction which is wound alternately over and under radiating pegs, after the fashion of basketwork. BATTERY.-This term indicates a chemical instrument for generating, or storing and then releasing, electrical energy. ‘he battery may be wet or dry according to whether the electrolyte or chemical solution is spillable or nonspillable. A "dry" battery would be better known as a "damp" battery. The energy obtainable from a battery is in proportion to the chemical action which takes place.

> BEAM TRANSMISSION.-A system developed by the Marconi Co. of Engdand of transmission by radiations con centrated and projected in a desired direction just as the beam of a searchlight is concentrated and directed. The system achieves a gain in secrecy, eco--nomy, and vange. ‘The wavelength of any beam system is invariably under 50 metres. "BEAT-NOTE.-The result of superimposing one oscillatory current on another in order to set up a third frequency or beat, Used in connection with heretodyne reception, See ‘Teterodyne."’ BEAT RECEPTION.-See "Tieterodyne." BIAS BATTERY.-Sometimes known as a "C" battery. Supplies a potential to the grid of a valve in order to make the valve perform its various functions at maximum efliciency and with a minimum consumption of "B" battery current. BLOCKING CONDENSER.-An-other name for a fixed condenser. Its purpose is to give a short path for radio or audio frequency currents, but acts as a bar to direct currest such as that which flows from the batteries. On the other hand, a condenser of the right value will pass radio frequencies but block audio freauencies. BODY CAPACITY.-See "Tlandcapucity." BROADCAST BAND.-The band of warelengths generally ranging from 200 to 550 metres. American receiving sets are constructed for reception only on this band of wavelengths. In England a large proportion of reeciving sets, by the use of plug-in tuning coils, can be adapted for the reception of wavelengths extending considerably over a thousand metres, so that many of the Continental broadeast stations which operate on the longer wavelengths can be tuned in,