John,
I have also been through this debate and called on the services of an
aviation radio specialist to help me. The conclusion was that placing the ELT
under the flat area of the XS bulkhead and the whip aerial up the aft of the
bulkhead was going to be the best location. The aerial would be mounted on a
metal plate of around 1 ft diameter and this in turn bonded to hardpoints
built onto the structure. Copper tapes would be attached to the plate to run
as a star from the aerial as far as is practical.
Alternatively, if you have an ELT that has a detachable aerial also supplied
then add a 90 degree BNC fitting and just use that aerial instead without the
groundplane. That way you don't have to worry about any cable breaks.
You will be surprised just how effective an ELT is without any aerial
attached. One builder in Auckland discovered this to his great embarrassment
when his ELT, without aerial attached, triggered in his hangar. Search and
rescue services were not very pleased!
NZCAA is about to issue a ruling that sport pilots and passengers can carry
personal EPIRBS instead of using aircraft based ELT's which is going to make
it easier for some. Of course this notice of ruling came out just after I
bought my ELT didn't it!!
Tony
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Tony Krzyzewski tonyk@kaon.co.nz
Managing Director Ph 64 9 520 4631
Kaon Technologies Fx 64 9 520 3321
Auckland New Zealand
Networkers visit www.kaon.co.nz
Aviators visit www.kaon.co.nz/europa/
and www.kaon.co.nz/saanz/
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