Glossary of Wireless Terms

Radio Record, Volume II, Issue 7, 31 August 1928, Page 29

Glossary of Wireless Terms

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

L.. * INSULATOR.--A term applied to all materials which form very bad conductors of electric currents. They do, however, allow high-frequency oscillations to pass when they act as the dielectric of a condenser. . See "Conductor." A substance used to prevent the loss of an electric current. The most common insulating mediums, or materials are air, ebonite, india-rubber, mica, glass, porcelain, paraffin wax, paper and oil. Also the term applied to the objects inserted in the wires supporting an aerial to prevent leakage of the high-frequency currents flowing in the aerial. INTERFERENCE.-A term used to represent a difficulty in separating the desired signals from others on a close wavelength; such interference is usually cured by increasing the selectivity of the receiver. Interference may be caused by allowing a high-frequency or detector valve to fall into a condition of oscillation, Howling valves cause interference. INTERMEDIATE STAGES.-Refers to the radio frequency stages between the oscillating or frequency mixing valve (first valve invariably) and the detector valve, which precedes the audio stages, in a super-heterodyne receiving set, INTERNAL OR INTER-ELEC-TRODE CAPACITY.-tThe proximity of the elements of the valve within the tube causes interaction between the. grid and the anode circuits. When such action is more than usually undesirable, special] valves with more widely--spaced electrodes may be used, or else special circuits such as those on the neutrodyne principle may be employed. ION.-A gaseous atom having a surplus or deficiency of electrons, the former being called a negative ion and the lat-: ter a positive ion. Ionisation is only met with in soft detector valves or certain gaseous rectifying units used for battery charging or eliminating apparatus, It formed the basis of action in. valves of ten years ago,

. IONISATION.-The liberation of charged particles of gas, known as ions, owing to the liberation of electrons from the atoms of the gas, generally due to collisions between the gas atoms. and high-speed electrons. See Jon. JAMMING.-Interference in the re-. ception of signals caused by signals from other transmitters. "JAR.-The British Admiralty unit of capacity being 1.900th or .0011 of a microfarad. | JUMBLE WOUND.-A _rough-and-ready unsystematie method of winding a coil A common example of. this is the radio-frequency "choke" coil used in short-wave receiving sets. {BATHODE.-See "Cathode" and "Anode." KEY.-The conventional name for the switch by means of which telegraphic messages in Morse are sent. ‘The circuit is made or broken as the key is depressed or released, KEY SWITCH.-A neat form of switch having many varieties in which only the short operating lever projects through the panel and jis visible. KILOCYCLE.-Represents 1000 .cycles. The practice is growing of quoting the ‘t?ansmission: characteristics of a station in, frequency in cycles ir .tead of ii. wave-length in metres. To facilitate this the figure is quoted in kilocycles instead of cycles. Thus 300 metres is a frequency of one .illion cycles, and this is quoted as 1000 kilo-cycles. KILOWATT (K.W.).-The unit used for measuring large amounts of electric power, being equal to 1000 watts, or 1 1-3 horse-power, 746 watts being equal to h.p. : KIT.--Usually associated with the word "Knockdown." Represents the complete parts for a radio set in an unassembled condition. a a ee ee ae ee |