I am using an ICOM handheld with their adapter for the headset. I have wired a
push-to-talk switch into the top of the stick and plugged it into the adapter.
I built a coax antenna for my Renegade and placed it behind the back seat. I
carefully trimmed it to resonance. It works well: I can hear aircraft in the
traffic pattern at an airport over 100 miles away. I can transmit for about 20
miles.
There are two things that affect the power output of any aircraft radio.
First, they have carrier controlled amplitude modulation. What this means is
that they put out only a fraction of their full power when there is no sound
coming from the microphone. When you speak, the power jumps up commensurate
with the loudness of the voice signal.
Secondly, since the manufacturer has no control over how the antennas work,
they have designed the transmitter to prevent it from overheating. If the
antenna is not properly tuned and matched, the signal that goes out is
reflected back into the transmitter. When that happens, the return signal is
turned into heat. To prevent the excess heat from damaging the transistors,
the output power is turned down.
So, it's important to have an adequate signal coming from you microphone, and
you need your antenna properly tuned and matched.
There's usually little difference between the transmitter and receiver
components of a handheld and the panel mount radio--just the extra bells and
whistles and displays.
Jim Vance
va...@claflinwildcats.com
