not taken place within 12 seconds, the
receive operation, the Rcv RF travels
antenna tuner hybrid A1 will output an
through the L-C coupling network to the
open on the No-Tune line to the tune
fault logic U1, Q3.
This will cause the
modulator/demodulator. No tuning takes
place while receiving. However, if a
Tune Fault signal to become +6v and the
tune start is initiated, all capacitors
modulator/demodulator to generate a
and inductors will be removed from the
beeping signal to the user.
If an ille-
gal frequency has been selected (under
To initiate a tune-up, the
PTT or CW KEY must be pressed.
2 MHz), then the Frequency Select Logic
inputs from the control panel will all
be at ground, and the Tune Fault line
Antenna Select Switch S1.
antenna select switch S1 has three
will again become +6v.
In routine operation (after the
tuning cycle), the Xmt RF is not sampled
by the rf sensor bridge. The +16v regu-
lated supply from the power amplifier is
position, the Xmt RF and Rcv
2-133. A L C .
The ALC voltage from
RF bypasses the antenna tuner module,
the rf sensor bridge is compared with
and the rf goes in and out of the BNC
a reference voltage at a differential
In the BNC and Whip posi-
The output is routed to the
tions, the rf is routed through the
Refer to the ALC
tuner to the BNC connector or Whip
paragraph in the modulator/demodulator
socket, depending on which has been
Note that this is
used during tune-up only.