| Glossary
for Vintage Technology |
| 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. See also Dry Battery. |
| 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. See also FM. |
| Anode |
|
The
positive plate of a valve, the point where, or the path by which, a
current enters the device. |
| 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. |
| 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. See also Accumulators. |
| 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. Link: Guide
to a good earth. |
| 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. |
| 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. Link: licence
statistics in Wales |
| 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 optimized 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. |
| 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 centimeters 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. |
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