On Thu, 23 Mar 2006 22:54:55 +0800, Stealth Pilot
wrote:

On 23 Mar 2006 00:39:43 -0800, "scottloftin"
wrote:

ATC has been complaining on and off about my radio being "weak",
"garbley" and just about every other word that describes a bad radio.
The #1 Com is relatively new, but the airplane is old. I tried the
light bulb trick as described in Jim's article, using the light bulb as
a simple wattmeter connected to the coax at the #1 COM antenna
connection. I get NOTHING when I key the mike and talk into it.

My avionics doctor tells me this doesn't mean anything. So far, he's
had me put in a portable PTT switch, put new mikes on 2 different
headsets, clean the coax connector at the radio, change the BNC
connector at the antenna and finally replace the antenna. I say it
means the coax is bad! It's an 8 watt transmitter so I soldered a 313
bulb to a BNC connector and hooked it up. Everything I learned about
electronics (I'm an EE for Pete's sake) says that the bulb should glow
brightly and modulate in intensity with my voice. Should I just change
the coax and be done with it?

from your description of the circuit surely there is nothing else left
to change :-)

you could try turning the master on :-) :-)
g,d,r.
Stealth Pilot

How about connecting the bulb right at the tray? As a "dummy load"
without any cable you SHOULD be able to prove the cable one way or the
other by elimination.

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