Brinzlee,
I bought one some time back from RS Components, but haven't got round to trying it out on the plane yet.
I did contact the manufacturer, RF solutions, to ask for more information - especially as to whether it needs a ground plane, but they were somewhat less than forthcoming...
My Question: I bought one of these from RS Components to use with a low power (500mW) transceiver, however the data sheet doesn't make it clear whether or not it needs a metal ground plane. Can you please advise.
Their Reply: The antenna would benefit from a ground plane, although it is able to be used without one.
Thinking about it, I suspect the 'PUK' contains a dipole, with the ends folded round inside the housing (like an 'S'). This would explain why it works without a ground plane. If this is the case, however, it will already be 3db down on a vertical unless mounted 'on its side', in which case I would still expect it to be significantly less efficient than a straightforward vertical dipole for the same frequency. The only benefit I can see is that it is clearly designed for fitting externally and can be easily made fully weatherproof.
Regards
Peter
