CCWN 75:39

  50 Khz, and 1 Khz symmetrical TTL signals, in addition to +5
volts, the VFO SAMPLE INPUT (SI ) and connection to the RECEIVE
OFFSET (RO) and TRANSMIT OFFSET (TO) jacks on the TEN-TEC .       
     A VTVM should be connected to the panel mounted OFFSET
SELECTOR switch at the center contact to monitor the DC voltage
being sent to the varactor diode in the TEN-TEC VFO. If a counter
is available, its input should be connected across the stabilizer
VFO SAMPLE INPUT (SI), to read the frequency that the VFO is
operating on.  Set the PM-l to about 3600 Khz. The VTVM should
indicate about 2.5 volts, and should be heard on the station
receiver at about 3600. As you move the tuning knob, the VFO
frequency will change, and the voltage will remain near 2.5v.
This is your indication that the u-.it is out of lock. Tune the
receiver to 3551 Khz, and move the VFO tuning to bring the VFO
towards 3550 Khz. The VTVM will suddenly jump down at least a
volt and then move up steadily to almost 5 volts. As you continue
to tune down, it will jump back to 2.5 volts.  The middle range,
when a change in the VFO position produces a change in control
voltage without a change in the VFO frequency on the station
receiver or frequency counter, is the locked position of the
stabilizer loop. The most stable position  within the lock region 
is the center of its range. This procedure is easier than it
sounds and is quite noticeable on the monitoring receiver. Do not
be disturbed if the counter indicates 3549.99 Khz rather than
3550.000 Khz since this one digit error is common on some
counters. Removal of the 500 Khz and 50 Khz drive signals will
cause the stabilizer output to go to Vcc or ground, depending
upon the logic state when the signals are removed.            
Another test is to lock up the loop, and then bring your hand
close to the VFO tuning capacitor. Observe that the control
voltage will change slightly to keep the VFO on frequency as your
hand capacitance changes the VFO circuit values by a small
amount.             The adjustment of the receive stabilization
on either 3549 or 3551 Khz is similar; remembering to place the
OFFSET switch into the RECEIVE position. The operator should
become familiar with all indicators of lock up and stabilization,
since they will be very important during the actual operation of
the CCW station.