>Having reached the stage of planning cable routes which separate as much as
possible power from feeders, can I mount the transponder aerial/antenna in
an outer underseat stowage? Either totally within the airframe or
protruding.
>
>I believe this position offers the shortest cable run (in line with design
requirements) and keeps costs down if the more expensive RG400 co-axial is
to be used. I hear tales of "frying the family jewels" with RF (perhaps the
aerial should go under the passenger seat!) and blanking by the engine when
the interrogating station is ahead.
>Your thoughts please.
Always keep any RF emitter as far away from the body as you can. RF is a
dangerous source of energy. Consider the effects of microwave ovens,
they're just a high frequency signal - much higher (frequency and power)
than aircraft radio's which makes microwaves more dangerous, but the
accumulative effects of lower frequencies can cause various problems from
infertility to cancer.
Also, the closer the emitter is to a large lump of metal (engine), the more
the signal will have a 'blind' spot, i.e. the signal won't go through the
engine.
And... the closer the emitter is to any other electronic equipment, the
higher the risk of RF interference in that equipment.
I'd say spend the money on the coax and move the aerial back as far as you
can.
Cheers,
Mark.
________________________________
Mark Jackson - +44 (0)7050 645590
europa-builder@ntlworld.com
http://harley.pcl.ox.ac.uk/~mark/Europa
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