Doug,
Measuring
DC resistance on the output BNC connector of the radio may in fact show a dead
short. It all depends on the electronic design of the radio. Some
designs have an inductor (coil) on the output pin to ground which would show as
a DC short, but that would be normal. Check the output power of the radio
with an in-line power meter (Byrd watt meter or similar) and check the SWR as
well. If you don’t have the equipment your local radio shop will
have it (or a ham radio friend).
RF
from a perfectly working comm radio can bother the EC2 and or EM2/3.
Close attention on shielding and grounding of the EC2 – EM2/3 and its
wiring is a must.
As
a second test, get a handheld comm and transmit while in the cockpit with the
engine running. Wave the handheld around in the cockpit while
transmitting. If you’ve got shielding problems, the handheld will
bother the EC2 as well as the panel mount radio.
Neil
Pilot and Ham radio nerd.
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of DLOMHEIM@aol.com
Sent: October-24-09 12:47 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Sam Hodges
Update
<snip> After a weeks vacation from work and the plane I came home
with a fresh mind and discovered a direct short to ground from the coax center
conductor to the radio case. A bad radio right out of the box".
We should be hearing about a first flight
in the next few months!