(c) If capacitor bypasses are not satisfactory, remove
3-8. Initial Checks
them, and use chokes in series with the leads from the
fields and armature terminals of the generator. Place
Turn the MIC GAIN control (4) fully
these chokes as close as possible to the voltage
counterclockwise until the switch clicks. Set the OFF-
ON-NB-CAL switch (1) to ON. Set the meter switch
(d) For the field lead choke, wind 12 turns of
(8) to PLATE and the EMISSION switch (2) to
No. 18 wire on a inch diameter powered-iron core.
LOCK. The transceiver is in receive condition during
For the armature lead, wind 12 turns of No. 14 or
warm-up, so the meter will read full-scale until the
larger wire on a 1/4 -inch diameter powered-iron core.
filaments have reached operating temperature. This is
(e) Ground the rear end of the exhaust pipe to
normal S-meter action. When the S-meter falls back
the car body with copper braid, using a radiator hose
to zero, the circuits will have switched to transmit
type clamp to secure the braid to the tail pipe.
condition and the meter will indicate pa plate current.
Read the no-signal plate current. It should be
In the following checks and adjustments
approximately 40-ma. If the plate current is other
here and throughout this manual, do not
than 40-ma, adjust the BIAS ADJUST potentiometer
leave the EMISSION switch in the LOCK
on the top rear of the power supply chassis to set the
position for more than 30 seconds. Damage
plate current to 40 ma. If the transceiver is to be used
to the equipment components will result.
with a linear amplifier, set the bias to produce 50-ma
idling plate current.
Section III. OPERATION
markings on the dial scale and set the controls
3-9. Starting Procedure
according to figure 3-5.
To turn on the Collins KWM-2/2A, set the OFF-
ON-NB-CAL switch (1, fig. 3-4) to ON. This turns
If the transmitter drive is insufficient or
on the power source being used with the Collins
receiver sensitivity is lacking, retune the
KWM-2/2A. Allow a 1-minute warm-up period.
trimmer capacitors according to paragraph
Set the MIC GAIN control (4) to OFF and
b. Refer to table 3-2 to determine the crystal fre-
the EMISSION switch (2) to LSB, USB,
quency corresponding to the desired operating fre-
or CW to prevent accidental transmit
quency and BAND switch (3) position. Insert the
condition before warmup or tuning.
appropriate crystal in the crystal board (12) and set
the BAND switch to (3) to the proper position for
the installed crystal.
The Collins KWM-2/2A must be operated
Be sure to insert the crystal in one of the
into a 50-ohm load with an swr not to
sockets corresponding to the band in which
Random length wire
the crystal belongs. A crystal in band C,
antennas or light bulb dummy loads cannot
for example, should be inserted in socket
be used. Conventional half-wave dipoles
1C, 2C, or 3C. Refer to table 3-2 for a
and beam antennas may be used at, or
list of crystal frequencies and operating
near, their resonant frequency. Exceeding
an swr of 2.0:1 can destroy the
c. Set the variable frequency oscillator (vfo)
components in the output stage of this
tuning dial (13) so that the bandswitch setting
(crystal band frequency lower limit in MHz) and the
a. Set the EXCITER TUNING (6) and P.A.
vfo tuning dial (13) setting in kHz add to give the
TUNING (7) controls to the desired operating
desired operating frequency.
frequency. Refer to the logging scale calibration
curves in figure 3-5. If the operating frequency is
outside an amateur band, ignore the amateur band
Change 5 3-6