Question about Spitfire Antennae ?

The tropicalisation package for the Spitfire Mk.V includes the TR9D, as in the manual which is commercially available. I would expect this to be a function of time, but would have expected the published volume to have the final amendment including the later radio.

IFF wasn’t linked to voice radios, they were separate radio fits. The MkII IFF used the two wires from fuse to horizontal tail, and was introduced in Spits in the UK from Sept 1940 onwards. It was phased out by 1943. The MkII came in several sub-variants, each one capable of responding to more and more radar wavelengths as they were introduced in theatre. The problem was permanently solved with the introduction of the ‘universal’ MkIII, which used a small aerial mast under a wing rather than the wires.

Exactly what IFF fit was carried would depend upon what interrogating radar the aircraft was expected to respond to at the time, in that theatre.

The aerial wire from mast to tail was fitted while the aircraft carried the TR9D radio. This was an HF radio, and the wavelength required as long an antenna as possible. When the radio was changed to VHF (the APs say TR1133, but in reality these were hand-built and rare, the ‘productionised’ TR1143 being the more common variant), the required antenna (1/4 wavelength) needed only to be 75cm or less. The aerial mast was used, with the actual antenna running up the inside. The wire was not needed, though the bracket to hold the wire often remained. Again, it depends what radios were used in theatre at the time. I suspect VHF.

The Tropical MkVs in Australia had later radio packs fiitted hence no aerial from mast to tail and no IFF from fuselage to tail.

Sorry Ben, I have accidentally misled you. The IFF wires do not run from the tailplane to the rudder but to a position on the fuselage on the roundel – typing error above is now corrected!

Not giving information to the enemy would be one consideration, but also it was dependent upon the level of the radar sets available on Malta – or elsewhere in other theatres. It is much easier to place a bit of kit on an aircraft than employ the full support structure worldwide. For example, the tropicalised Spitfires had an earlier generation of radio than the UK ones.

Yes the horizontal tailplane antennae, the aircraft I’m building (GN-H 249 Sqn) doesn’t have the post on top of the rudder so can’t see it having the wire from there to behind the cockpit, the lack of the IFF aerial makes sense as I suppose they didn’t want to risk it falling Into enemy hands.

Thanks.

Do you mean from both sides of the (horizontal) tailplane to the fuselage, entering at a point on the roundel? In which case that is the IFF aerial, and at least initially this was not present on Malta. I don’t know for sure what the equipment fit was in 1942, at the time of the Spitfires. Or do you mean the aerial that runs from the fin (vertical tailplane – but not often described that way) to the aerial mast behind the cockpit? This was dependent upon the type of radio fitted, and was replaced by a wire that ran up the mast.