The designs for this transceiver were developed by RSRE and Pye in 1940 and after producing a number of MkI equipments it then continued in development, emerging as the MkII (seen here) in 1941 and finally the MkIII in 1942. The sets were used by the British Army up to the early 50s and by Canadian Divisions during WWII. Besides being built in the UK, the sets were also produced by a number of different manufacturers in Canada and the USA. Once designs had been customised for ease of sourcing American components, by liaison between Pye and a four man Canadian team, the firms selected to manufacture the sets were Northern Electric, Canadian Marconi and RCA Victor in Canada; and Zenith, RCA and Philco in the US.
Many MkII versions were made for the "Lend-lease" program in which much military materiel including not only smaller items such as these but also aircraft such as the Spitfire were sent to Russia to combat Nazi aggression. As a result of this programme many of the 19 sets still around have dual English and Russian legends on their front panels.
Physical dimensions are 17.5" x 8.5" x 12.5" and it weighs in at 40 lb.
A range of ancillary equipment was used with the set, including dynamotor based power supply, ATU and whip aerial, combined headphones/mic and sometimes a high power amplifier. Performance wasn't wonderful, as the set used grid modulation which reduced the range, compared with the more beefy technique of plate modulation. However it should be remembered that the set had a limited design performance in keeping with its intended operational use. As the set covered three amateur radio bands (160, 80 and 40 metres) it was popular in the 50's when the availability of commercial equipment was limited and expensive and of course the norm was amplitude modulation in those pre-SSB days. I remember using the set on "Top Band", the high end of which was just achievable.
The set provided HF inter-tank and tank-to-HQ R/T, CW and MCW comms, over the band 2-8MHz and had a range of 10 miles R/T or 15 miles CW. The VHF inter-tank set used the "super-regenerative" technique and had a range of 1000 yards using a small band centred on 235MHz. There is also an intercom facility, using a pair of 6V6s, for the tanks crew. The HF part, the A set, has an integral mechanical feature enabling, by means of a flick switch to rapidly change between two frequencies.
Use of the VHF part, the B set, was phased out in the 1950s as the Larkspur range of VHF FM equipment came into service. The Royal Armoured Corps replaced their latest modified 19 Sets with the very similar C12 in the mid-50s and this in turn later by the newer C13.
This example is a MkII version made for "Lend Lease" but probably never delivered to the Russian Army.
On the right is the main transceiver tuning control and on the left the tuning for the 807 power amplifier. The square centre pieces are used for presetting frequencies making it easier for the radio operator in the tank to maintain his place in a net when the tank was driving through brick walls etc.
Bird's eye view showing:-
Top left... Intercom amplifier
Front left... VHF transceiver
Centre... HF transmitter output stage
Right..... HF receiver
Rear... Receiver/transmitter IF amplifier
End view showing most of the 15 valves
|In this US sourced example the EB34 has been replaced by a dumpy little metal 6H6 and the red valve in the centre area which was known by afficianados of government surplus kit as a "Red Sylvania" is an EF50. The British version of the EF50 was usually in plain aluminium and was one of the new high performance valves specially developed for military equipment. Inside the box adjacent to the Intercom Amplifier is an unusual twin-horned triode which is illustrated in the section of this website for Unusual Valves.|