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Thread: Fortress aerials

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    Default Fortress aerials

    Am trying to pin down the function of two aerial types mounted on RAF Fortress IIAs, IIs and IIIs. One is a whip aerial just to port of the aircraft centreline and just ahead of the crew hatch below the nose - it seems to have been common to all USAAF and RAF Fortresses. The other is a short, probe-like aerial each side of the nose a little below the rearmost window. Am told it's length would indicate a frequency of 200MHz and that, as a pair, it was for a homing device. Any ideas?
    Thanks and regards:
    Robert

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    Robert,
    The ones on either side of nose are probably those for the AN/APN-2 Homing Beacon equipment. Hopefully some clued up bod on this Board can enlighten us more on how this equipment works. I think it is an approach aid for landing in poor visibility, and was common on all medium and heavy USAAF aircraft (and probably on most Navy heavier aircraft as well). I believe that similar equipment was also fitted to larger British aircraft later in war (Lancaster, Sunderland, etc). The AN/APN-9 was possibly an improved version of APN-2, and was definitely fitted in later C-47s, Sunderlands and Hastings. APN-2 apparently worked on 176 M/Cs and was used for "Navigation". However I had better leave anything further to the radio experts on this board before I really put my foot in it.
    David D

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    Hi Rob
    I don't know for sure but the whip aerial is probably the reflection of the introduction of the higher frequency VHF radio for voice communication. Spitfires and Hurricanes had voice communication for the BoB but this was via a lower frequency set fed via a wire aerial that was strung from a short mast behind the cockpit to the fin. Look at later marks of Spitfires and you can see over the years the replacement of the mast and wire by a whip aerial.
    There is a good chance that the newer equipment was American built, using their greater manufacturing capacity
    Regards
    Dick

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    Are you sure the pair of "aerials" "each side of the nose a little below the rearmost window" aren't the pitot head fairings - there was one port and starboard around where you have described for the early B-17s before the nose turret was introduced.

    A

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    Thanks all.
    It would appear that the lower whip aerial was for the radio compass. As for the probe - not confused with the pitot head fairings :-) - they could be related to the AN/APN-2 Homing Beacon (Rebecca) although the aerials I have seen on the Duxford Radio Society site are of the Yagi (rod) type rather than looking like sharp probes.
    Regards:
    Robert

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