This fine old receiver made in 1939,
in original drab livery, tunes to two VHF bands, 25 to 40 Mc/s
and 38 to 66Mc/s and has all the features one would expect in
a communications receiver. The valves used are octal types, with
the exception of the UX4 rectifier, as follows:-
RF stage... 1852 (same as a 6AC7); Mixer... 6L7; Oscillator... 6J5G; 1st IF... 6K7; 2nd IF... 6P7G; Det/AF... 6Q7G; AGC... 6H6; Output... 6F6G; Rectifier... 80.
It's a single conversion superhet with an IF of 1.6Mc/s.
Colour is original and could be described as dried mud.
At least the rust spots aren't that obvious!
Very
similar to 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.
It uses standard high performance war-time valves as follows:-
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
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.
In 1956 the R1392 could be had for £6/19/6d (almost £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.
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 Approach Radar".
Apart from the area immediately surrounding airfields, the country's airspace is divided into named zones or "Sectors" and each is assigned a specific frequency.
Adjoining airspace also has its allocated frequencies as are areas associated with major airfields such as Manchester.
In addition there are general information frequencies, and a distress frequency, 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.
For general interest I shall later include a listing for UK airports and the owner of a suitable receiver can eavesdrop on local goings-on in the air.
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