In a message dated 5/3/2008 3:01:31 AM Eastern Daylight Time,
europa-list@matronics.com writes:
Have others had difficulity with the dipole in the rudder causing problems?
Hi Jim,
FWIW, I installed an AAE (available from ACS) dipole COM on the rear my
sternpost, forward of the rudder. I installed an AAE transponder antenna, also
a
dipole, on the right side of the fuselage (inside), about 12 inches in front
of the rear bulkhead. Both antennae work beautifully and the only thing I
notice is the card compass swings slightly when I key the transmitter. I don't
see this effect when the transponder keys. I swept both these antennas
individually and with their respective feed lines and the SWR characteristics
are
flat across their respective bands.
Do keep your coax separate from everything else. I ran my coax for the COM
and transponder down one side of the fuselage and the rest of the wires down
the other side. Avoid placing any other wires near the coax termination's as
best you can, as RF leaks sometimes occur at the connectors and can cause
problems. Use good quality coax and connectors, IOW, not Radio Shack crap. Amp
makes excellent BNC connectors and they are available from Allied, Digikey and
many other suppliers. I prefer solder on center pins if you can find them,
with crimp on barrels. The clamp on screw type BNC connectors are garbage. Be
sure the shield makes good contact with the barrel of the BNC. Spruce has very
good RG58 coax that is aircraft rated. I did have to spring for a precision
cable for my Garmin transponder to meet Garmin's 1dB cable insertion loss
requirements, though. It wasn't cheap, but the performance I'm seeing was worth
every penny.
I'd be happy to bring my sweep test gear and SWR meter to Rough River if
anybody needs something looked at. I have the capacity to sweep anything from 30
Mhz to 3.3 Ghz. I also have a Bird precision watt meter for checking power
output at COM and transponder frequencies.
Hope it helps!
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Currently down for cowl work
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