Steve -
Especially the xponder antenna cable should not be run in bundles containing
other
wires running 14V power; avoid on VHF. Installing shops and even factories
do it all the time and often get away with it, but I'd still separate them.
COM may affect NAV only on xmit if their coax bundled together, but I'd still
separate them too. Takes only an inch or two.
The tips of a dipole are the worst place to have metal anything. It should be
separated by 24" as best you can. Although in a sense the tips do no work at
all, the length of the element is what tunes it, and nearby metal detunes it.
Also, the distance you have between nav and comm may be evidenced on the nav
display when you key the mike.
Energy radiates at 90-deg. to an antenna element, so curvature affects its
radiation
pattern. I think what Archer is saying is that no practical antenna
installation
has produced a perfect radiating pattern from Marconi's day forward,
so a little added curvature is not too bad.
This will sound like the other advice you got, but the NAV antenna on the bottom
may be noticeably worse than mounted on the top of the fuse, due to proximity
of the pitch tube and rudder cables, aggravated by its curvature. VHF nav has
the annoying problem where the avionics mfr need only provide enough sensitivity
to meet FAA requirements for "service volume," relating to reception distance.
Else there's potential for interference from VORs of the same frequency
if too sensitive. Design is then further premised upon an antenna installation
of typical adequacy. I'd either install it so it can be easily moved later
if need be, or just plan to affix it later to the top. Needs only blobs of
RTV if Archer permits and duct tape to hold it while curing, with access through
the "D" panel.
Regards,
Fred F.
> I've had it with these antennas. I don't know much about them and
> every time I tell someone how they're going in, I get, "whatever
> you do don't do that"....nav and com wires, (RG 400) run down the port
> side. The transponder wire runs down the starboard side with the
> battery wires. The Nav has one tip running under the battery wires.
> Is that going to mess up reception? The com is mounted to the port
> side wall. It's curved, I know, but Bob Archer said that was ok.
> http://idisk.mac.com/sdunsmuir/Public/bob1.jpg
> http://idisk.mac.com/sdunsmuir/Public/bob2.jpg
>
> Thanks,
> SteveD.
> P.S. It's a radish... Don't ask....
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