Hi Arnaud,
It is quite surprising you found a TR9D in a Battle!
By early 1940 there were essentially the following radio sets in RAF aircraft:
- TRF (R1082 + T1083) used in all light and medium bombers (=all RAF bombers including the Battle). Operated in the 111kHz to 15 MHz bands.
- TR9D (R1120 + T1119) which was used in early Hurricane and Spitfire fighters. Operated at 4.3-6.6 MHz. Plus a TR9J version used by Coastal Command.
- TR1133 (R1137 + T1136) introduced end 1939 for Hurricane & Spitfire fighters. Operated 100-120 MHz.
The web site forwarded by Mark shows the correct R1082/T1083 as used in Battles. The only explanation for a TR9D inside a Battle is that creative ground crew on a mixed Hurricane-Battle airfield mounted a Hurricane radio inside a Battle. Note that performance of all these radio sets was bad, only in June a much improved rasdio was introduced.
Regards, Pieter