Re: NEC-LIST: Airframe antennas for HF communications

In message <9807252018.AA24260_at_fs1.ece.ubc.ca>, Mr Phil Ede
<philede_at_fastnet.co.uk> writes
>
>I use NEC to generate the radiation pattern of transmit and receive
>antennas for use with ICEPAC, which I now need to use to predict the
>coverage performance expected by an air-traffic control ground
>station. Can anyone please advise me of the approach I should use to
>characterise the antenna performance expected on a typical large
>airliner? I realise that there are several different types with
>different performances, but there should be one which could be adopted
>for the purpose of determining the service probability.
>
>To complete the job I also need a figure to characterise the expected
>receive noise level.
>
>Can anyone help?
>
>Thanks
>
>Phil Ede
>

-- 
Hi Phil
I used NEC to model HF antennas on aircraft in my previous job at
British Aerospace, though not for airliners unfortunately and we didnt
publish any of our work.
Some good papers are out there on modelling aircraft antennas in the
ACES journals. A good one for HF antennas is in the March 1994 ACES
journal 'Some examples of the prediction and validation of near field
dependent aircraft HF Antenna Parameters using NEC' by Jeff Cox of the
Defence Evaluation and Research Agency. There have also been papers on
modelling HF on helicopters but I cant remember which ACES journals
they were in.
My previous experience indicated that NEC was very useful for the
radiation patterns but didnt provide much help on assessing the
efficiency of HF antennas which can be a less than 1% at 2 MHz. This
typically requires prediction of the radiation resistance and
measurement of the combined radiation and loss resistance on the
actual aircraft.
In my present job at National Air Traffic Services we are looking at
performing similar studies to yours for the VHF and UHF ATC radio
stations. I'd welcome the chance to discuss our/your work further.
Regards
Michael Bradford