REFLECTOR: Nav/Comm Coax in FB Wings

Dave Black dvblack at comcast.net
Mon Aug 28 14:43:43 CDT 2006


bdtopp at comcast.net wrote:

>    I am having difficulty determining which of the coax cables exiting 
> the wing roots is the Comm cable and which is the Nav cable.

I remember a few years back when I asked Alan Shaw this question, he 
suggested I pull on the cables. Since the Comm cable is longer, it would 
stretch more.

That test proved inconclusive for me, but I was able to determine which 
was which through the use of an antenna analyzer. Connect it to one 
cable or the other, then run your hand along the wing or winglet. When 
your hand passes the associated antenna antenna, you'll see an increase 
in SWR on the analyzer. The NAV antenna is in the wing, while the Comm 
is in the winglet.

If you don't have access to an antenna analyzer or SWR meter, just 
connect the antennas one way or the other. No harm will be done if you 
get it wrong. But you'll get better reception one way than the other.


dave black


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