Glossary of Wireless Terms

Radio Record, Volume II, Issue 12, 5 October 1928, Page 29

Glossary of Wireless Terms

From week to week we give here asection of the glossary of wireless ternis from the "Listener’s Guide."

%@ PRESSURE.-A term synonymous with voltage. PRIMARY.-Any circuit in which a ‘transierence of energy from one cell to another takes place (as in transformers, loose-coupled tuners, ete.) is distinguished as to its two coils by the terms primary and secondary, the former being the circuit in which the initial energy is flowing and the latter that to which the transference is made. PRIMARY BATTERY.-A baitery of cells in which the electric current is generated by chemical action as distinct from a secondary, or storage battery, in which an internal ‘chemical change is wrought by the application of an external current, when the battery is said to be charged; this current is given back-or a considerable portion of iton discharge, when the chemical change is reversed. PROTON.-A _ positive particle of electricity. It is now supposed that each atom of matter consists of a nucleus formed by a proton and surrounded by a ring of satellite electrons. The nature of the matter is determined by the number of these particles and their arrangement.

RADIATION.-Wivreless messages are propagated by the radiation of energy from the transmitting aerial When a receiving set is allowed to "oscillate" (q.v.), a weak radiation occurs from the receiving aerial also,and causes interference with reception by other radio workers within range. RADIO.--Colloquially, an alternative term for wireless. Used in conjunction with the word "frequency," it signi‘yiies the oscillations received by the aerial ‘in their passage through the set before )rectification, which educes the energy ‘from high-frequency oscillations to lowfrequency uni-directional pulsations. They are roughly reckoned as being greater than 10,000 cycles per second in contradistinction to audio-frequencies, which are also roughly reckoned as being below 10,000 cycles. RADIO FREQUENCY.-The oscillations as received on the aerial and passed through high-frequency amplifying valves up to the point where they are rectified by crystal or detector valve, are said to be of "high" or "radio" frequency. Frequencies above 10,000 per second are usually reckoned to be at "high" or ‘radio’ frequency. RANGE.-Refers to the distance over which messages can be received with a given equipment, or the distance to which they can be transmitted for reception with an average set. Improvement in reception range usually necessitates an extension of the high frequency amplifying section of the set, presuming that the efficiency of the existing apparatus is beyond reproach. PPPPLLL PLL ALL PLL LLP LLLP LPP PPP PIPL PP

RATIO.-Used in various senses in radio matters, but particularly in relation to the respective numbers of turns in transformer primary and secondary windings. According to whether the primary has a greater or lesser numsber of turns than the secondary, the output of the transformer is said to be "stepped down" or "stepped up" in relation to the input. REACTANCE.-See "Inductance." REACTION.-By coupling either electro-magnetically or electro-statically, the plate circuit of a valve back to the grid circuit of the same or a preceding valve, a portion of the amplified energy in the plate circuit is fed back into the grid circuit, from which it again passes through the valve and is re-amplified. Great improvement in signal strength is thus obtained, but if the coupling is made too tight the valve may fall into oscillation when not only are the signals badly distorted, but a continuous wave is radiated from the aerial causing interference with reception over a wide area. REACTIVISATION.-A simple and efficient method of rejuvenating valves which have gone dead. It can be performed by an apparatus which is manufactured for the purpose, or by simpler

methods. It 1s even applicable to valves which have through ‘ong and faithful use lost most of their activity. A simple method is to turn up the filament of the valve to normal brilliancy, then reverse the polarity of the B battery, connecting the plus to the plus A battery, and the minus to the side which normally takes the plus B. Leave the valves connected in this manner for a full hour, then turn the filament current down to its lowest point and leave the current on for another half-hour. It will be found that an hour and a half of this treatment is sufficient in most cases to rejuvenate the valves, but in cases where the valves are unusually dead. the treatment may be necessary for double that time. After treatment the valves should be allowed to cool off. and then the batteries are connected in their regular manner. Tyne 200-A valves cannot be treated in this manner successfully. as once this type has Jost its sensitivity it is practically imnossible to rejuvenate. The method will, however, brine back to normal all 199, 201A. A Hi-Mu. and power valves which have lost their vim. In testing this method, a set of valves have been used which were so dead that absolutely no signals could be heard. After the process was completed, a matter of nearly three hours, the valves worked as well as ever. RECHTVER.-A term used indiseriminately to designate either a receiving set as a whole or the telenhone or Ioudsneaker receiver, Fither use is quite correct. but to avoid eonfnsion. the HWmitetion of the term to describe the set. and the use of the words "telephone" or ‘telenhone reeeaivar"’ ja reeammaended,