This is an improved version
of the R1392, probably the RAF's most common receiver for reception
of aircraft during WWII and up to the early 60s, the set receives
AM in the band 100 to 150MHz. See also the R1132A.
A crystal was plugged
into the socket, lower left, which tuned the receiver to the
desired channel. There are two obvious differences between this
receiver and the R1392. Firstly you'll notice the label "ADJUST
FOR MAX SIGNAL" next to the meter. This is an aerial trimmer.
The major difference however is the use of 9.72Mc/s rather than
4.86Mc/s for the IF. This would have improved 2nd channel reception
but will have meant that crystals for the two receivers will
differ. The required crystal will be (Fs-Fif)/18. For example
to receive Bournemouth Airport ground frequency will require
a crystal of 6.221Mc/s rather than 6.491Mc/s for an R1392.
Power requirements are met by
a matching mains unit, the Type 234 which carries an internal
switch also allowing it to be used for another type of receiver,
the R1132. Power consumption of the receiver is 250 volts at
80mA and 6.3 volts at 4 amps. Physical dimensions are 19 inches
x 10 inches x 10 inches. A very interesting feature of the set,
which was made by Ekco, is the internal metalwork which is said
to be entirely silver-plated, although it looks to me more like
the colour of cadmium plate. This example needs cleaning as sticky
tape covering the various tuning and trimming points has left
In 1956 the R1392
could be had for £6/19/6d (about £6.98 in todays
monopoly money) which then represented the best part of a working
man's weekly wage. The matching power unit was then priced at
£4/10s (£4.50). Not many people could afford to buy
this sort of stuff unless they had saved up their pocket money
for a very long time.
A standard 6-pin Jones
plug carries the power from the cable to the Type 234 PSU.
Note the commercially
coded EF54 valves.
Note some modular construction.
The RF front end unit (inboard) and the Oscillator unit (RH edge).
The receiver uses fifteen
standard high performance war-time valves as follows:-
The layout on the side of the
chassis shows the services codes. Commercial equivalents are
1st and 2nd RF amplifiers EF54;
1st Local Oscillator SP61; 2 Oscillator Multipliers EF54; Mixer
EF54; 3 IF Amplifiers EF39; AGC Amplifier 6Q7; Audio Output 6J5;
Muting EA50; BFO 6J7; Demodulator 6Q7; Noise Limiter EA50
the manual for this receiver
Convention has it that aircraft,
except for long distance communication, use AM voice transmissions
in the band 118-136MHz.
In the UK, frequencies in that
band have been allocated to all airfields large enough to operate
Air Traffic Control.
In many cases a particular airport
will have frequencies for its "Tower", from which the
whole airfield is visible; "Approach" from which landing
instructions are issued; "Radar" which can be used
as an adjunct to the Approach facility in bad weather; and "Ground",
an alternative frequency to which aircraft will switch if the
Tower has further traffic. There are also additional frequencies,
assigned to larger and to military airfields, such as "Precision
Apart from the area immediately
surrounding airfields, the country's airspace is divided into
named zones or "Sectors" and each is assigned a specific
Adjoining airspace also has
its allocated frequencies as are areas associated with major
airfields such as Manchester.
In addition there are general
information frequencies, a distress frequency (see
the TR2002), and a host of military allocations for training
and operational flights.
Transatlantic traffic uses HF
until it comes within VHF range of UK airspace.
English is used for the large
majority of voice traffic, but because of the repetitious nature
of many transmissions, transmissions are often stacatto in form,
and this coupled with the use of jargon, and the accompanying
whine of poorly stabilised power supplies, make it often difficult
to understand what is being said. However, listening to the aircraft
band is a common past-time for many owners of scanners and many
transatlantic carriers set aside a channel in their in-flight
entertainment repertoire for travellers to listen-in to the chit-chat
between Air Traffic Control and their pilot.
general interest click to see a listing for UK Air-Band frequencies.
These are Bournemouth Airport
APP: 119.475 MHz
ATIS: 121.95 MHz
GND: 121.7 MHz
TWR: 125.6 MHz