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Vintage Technology: Glossary
Some of the terms used in this web site are now obsolete or specific to the UK in the 20th century.  To help you, here are a list of words or phrases that may help you understand the entries a little better.

Accumulator A battery using the lead-acid system (otherwise known as a wet battery).  Before mass electrification of the UK this was the only way to power your wireless set.  Often a boy from the radio shop would collect your battery (on his bicycle) to take it for charging. 
Amplitude Modulation (AM) A way of encoding a signal onto a radio wave used from the first days of sound broadcasting radio.  The signal (say a piece of music) is superimposed on the strength of the radio wave.  A radio will then rectify this signal, take out the radio frequency component and amplify this signal to a loudspeaker. 
Anode The positive plate of a valve, the point where, or the path by which, a current enters the device.  Anode is also used for the positive end of many other things such as batteries, diodes and other electrically active items. 
Bakelite The first form of plastic invented by Leo Baekeland.  Using a resin based petro-chemical formula formed under high compression, bakelite was originally used as a poor-man's substitute for wood - especially around World War II when there was a shortage of wood.  In the late 1940's, however, it was recognized as an innovative and individual material for radio cases (and numerous other products like telephones, hair dryers, clocks etc.) in its own right.  Certain types of early bakelite, like cream and patterned versions, were hard to make, easy to break and hence very collectible.
Band-spread Term used to flag the spreading of a tuning range over several tuning scales.  Often used for Short Wave as stations were tightly packed together and difficult to tune.
Cat's Whisker Refers the to metallic contact on a crystal detector. A thin piece of metal (often copper, brass or silver) pushed against a crystal to form a rectifying contact.
Cathode The negative plate of a valve, the point where, or the path by which, a current leaves the device.  Cathode is also used for the negative end of many other things such as batteries, diodes and other electrically active items. 
Coil An electrical device created, literally, out of a coil of wire around a "former".  This device has an electrical property called inductance that, when used in conjunction with a capacitance, can make a circuit's response depend on the frequency of the current placed upon it (resonance or tuning).
Condenser These days known as a capacitor.  An electronic component that holds charge and can be used to block DC current whilst passing AC signals.  Values for condensers were usually measured in micro-Farads or pico-Farads (F or pF).
Console No, not a games machine. The word console was used to describe a large-cabinet radio, radiogram, gramophone or TV.  They were usually floor standing, major pieces of furniture.  Other terms used (progressively smaller) are consolette, table top, transportable, portable and compact.
Crystal Refers the the rectifier in a crystal set.  Most crystals were lead-based Galena, but Perikon ( copper pyrites crystal with zincite) was also popular.
Crystal Set A radio receiver that used a crystal detector and a few other components to tune the radio signal.  Typically they had no amplification, so needed headphones and a strong signal to work.
c/s or CPS Measurement of frequency, the cycle being the period it takes to complete a full sinusoidal wave.  The higher the frequency the higher the c/s figure and the lower the wavelength. Outdated terminology; Hz (Hertz) or kHz is now used.  See also Wavelength.
Currency The currency in the UK up to the early 1970's  was the archaic system of pounds (), shillings (s) and pence (d) or LSD.  There were 20 shillings to the pound and 12 pence to the shilling.  As you can image, this made early financial comptometers quite complex. There were other common units of money like the crown (5 shillings) and guinea (gns) (one pound and one shilling).  See also Purchase Tax.
Detector An early name for a device that "detected" radio signals.  A detector is actually a rectifier that only passes the (intermittent) DC component of an AC signal - thereby allowing the signal to be used as a representative voltage to pass to an amplifier.  Early detectors were made from carbon powder or crystals of Galena touched by a thin wire of copper, brass or sometimes silver (the Cat's Whisker) or carbon 
Diode A two-electrode valve (or more modernly, electrical device).  A diode is more commonly associated with a valve that lets current pass from the anode to the cathode, but not the reverse, thereby rectifying a signal or current.
Drive cord Every radio restorer's nightmare.  The drive cord was a cotton or nylon string (or metal  wire) that transferred the rotational motion of a tuning knob to the tuning capacitor.  Getting just the right tension to avoid cord slip and the often convoluted flow of the cord makes replacement difficult.
Dry Battery A battery that was sealed and used chemical pastes to generate electricity.  Often disposable and sometimes rechargeable, these replaced the early lead-acid accumulators using in early wireless sets.  It is difficult to imagine the practicality of early portables without dry batteries.
Earth The reference point for zero electrical potential.  An AC voltage swings positive and negative in relation to the earth (or ground) potential.  Electricity generating stations literally have a robust connection into the ground to set this level.  Early radios used an earth connection to a moistened metal stake in the garden or connection to metal water pipes.  A Good Earth was essential in a radio to allow for the maximum potential difference to be built up in an aerial receiving radio waves.
Frequency Modulation (FM) A way of encoding a signal onto a radio wave used from the mid 1950's in the UK via VHF.  The signal (say a piece of music) is superimposed on the frequency of the radio wave.  A radio will then compare the change in signal ratios, take out the radio frequency component and amplify this signal to a loudspeaker.  See also AM.
Fringe Area In the early years of mass TV take up, London and the Midlands were the first areas to have TV transmitters.  Those people situated at the edge of acceptable reception power were in the "fringe".  Special fringe models were introduced with boosted RF amplification to cater for this market.  A lot of early wireless sets had a similar local / distant switch to stop nearby transmitters flooding the sensitive radio circuitry.
getter An element used in the manufacturing of valves (early; Magnesium) that was ignited after the valve was sealed in order to remove the last bit of gas in a valve - thereby hardening the vacuum.  This usually left a (gettering) residue on the inside of the glass envelope.  When first used, the public was not happy about this "ugly mess" and reacted against it.
IF Intermediate Frequency, see Superhetrodyne.
LED Stands for Light Emitting Diode, used singularly or arranged in (red) seven segments for mid 1970 calculators.  The physical LED is very small so displays were either made up of rows of LEDs or plastic lenses were used to magnify the image.
Licence (TV, Radio or Sound only) In the UK, the BBC is funded by public money rather than advertising.  This money is gathered by the payment of a licence.  Initially this was a radio licence, later came TV licences, sound only licences (for radio) and colour TV licences.
Light Programme, The Name for the BBC radio station, commonly known today as Radio 2.  Broadcast light entertainment such as popular music, comedy, plays etc.
Listening-in Phrase used from the early 1920' to describe the act of listening to the radio.  Early crystal sets with headphones produced little volume so great concentration was required to "listen in" to the stations.  The natural progression of 'Look-in' was used in the early days of TV but is more remembered from the mid-1970's when the TV-based magazine called "Look-in" was published.
Long Wave (LW)  A term to loosely define the tuning area of 1000-2000m wavelength.  This band was the first generally adopted are of radio station transmission due to both the lower (easily generated) frequencies and the longer distance penetration.  See also Medium Wave, Short Wave and VHF.
Mains (AC or DC) Refers to the electricity supplied by a main source, rather than a battery.  Early domestic mains was Direct Current (DC) which was eventually superseded world-wide by alternating current (AC).
Magic eye Term used for a number of vacuum tube-based devices that displayed information.  More commonly they were small valves with a small phosphorous screen (like a CRT) which either became brighter, or displayed changing patterns on the change of received radio signal strength.  Decay over time, getting dimmer, so a radio restorer's nightmare.
Medium Wave (MW)  A term to loosely define the tuning area of 180-500m wavelength.  This band was rapidly adopted after Long Wave as the number of radio stations increased:- the higher frequencies allowing a greater number of stations to be transmitted.  See also VHF and Short waves.
Microphony A fault created by the mechanical vibrations interfering with the performance of a valve.  For instance, site a valve too near the vibration of a speaker and the movement will cause the "nodes" to vibrate.  This causes a change in electrical characteristics as spacing of valve components changes the electron flow properties.  The more rigid the valve design, the lower the microphony.
Pick-up Term used for the playing head of a gramophone (record) player.  They could be either magnetic (coil or magnet moves to create signal) or crystal (pressure applied to piezo-electric crystal) based.  Most radios came with a "Gram" socket (and selection switch) to send the pick-up signal into the amplifier section of the radio.
Purchase Tax (PT) The early form of Value Added Tax (VAT) used in the UK.  Purchase tax was used by the government to control the spending of the public along with hire purchase and deposit rules.  You will find most of the price information in this site exclusive of purchase tax, but when available the phrase "plus PT" will be used.  See also Currency.
Radiogram A combination of a radio and gramophone (record player) in one cabinet.  I only put this in as someone asked me the other day!
Rectifier (valve) A device for changing AC mains to a DC potential.  Usually the rectifier created a pulsed power that was smoothed by a large capacitor.  Rectifiers on this web site were either valves (like the UU series) or metal (early semiconductor devices).
Short Wave (SW)  A term to loosely define the tuning area of 10-90m wavelength.  This band allows extremely long distance transmissions as it can be bounced of the inner layers of the earth's atmosphere (noticeably at night when the sun's activity is not masking the signal).  The shorter wavelength also allows stations to be spaced at tight intervals making this waveband "live" with transmissions.  However, this made for a difficultly in tuning stations accurately, so band-spread was sometimes used. See also Medium Wave, Long Wave and VHF.
Superhetrodyne Basically, it is difficult to make high frequency circuits that respond in an even way to a large range of frequencies that are used in radio reception.  This methodology mixes the signal received with another (variable) frequency thereby converting it into a signal of a known fixed frequency (known as the intermediate frequency or IF).  Subsequent stages of a radio can then be optimised to work at a particular frequency and hence perform much better at tasks like amplification.
Sutton Coldfield The second place in the UK after London to have a TV transmitter in 1952, primarily for the Midlands and Birmingham area.  Reception, however, was achievable from as far away as South Wales.  In fact, as I am lucky enough to live on a very high hill, I can still receive these signals on my standard domestic TV today.
Triode A valve (or modernly, an electrical device) that has three electrodes; and anode, a cathode and a third electrode (usually a grid) that allows the modulation of the current between the other two.
Valve Electrical device that controls the flow of current - hence adopting the word used for water and air valves.  Using a number of electrodes sealed in a vacuum various properties of the current flow could be controlled.  Often fabricated out of glass, but sometimes from metal there shape led to the American name of tubes.  Today transistors (or multiply integrated transistors on silicon chips) perform the same function.
VFD Vacuum Fluorescent Display used on calculators of the 1970s and still used frequently today in Hi-Fis and cars.  They work like a miniature CRT with a evacuated glass body electron emitting grid and fluorescent coating that glows when stimulated.  They initially were available in shades ranging from blue to green and (Panaplex displays) orange.  They gave a large bright display of digits but were heavy and power hungry.
VHF Stands for Very High Frequency, but is more synonymous with FM radio broadcasts in the UK started in the early 1950's.  The VHF broadcasts were of much higher bandwidth (and hence aural quality) than the AM system used for Medium, Short and Long waves.  The UK adopted a band of 92Mhz to 108Mhz for the VHF radio broadcasts.
Wavelength The physical length of a complete period of sinusoidal radio wave.  Usually measure in meters or centimetres for long and short wavelengths respectively.  Used colloquially as the "position" of a station on a tuning scale.  Modern use of the word wavelength such as "on the right wavelength" or even "in tune" to mean that someone understands perfectly.  See also Cycles per second.