TM 11-S820-55-1 2
(2) Close-talk into the microphone, increasing the
relay trips, increase the ANTIVOX GAIN (R45)
VOX GAIN control setting until the vox relay just
setting to minimum point necessary to prevent the
operates. For vox operation, it is desirable to close-
speaker output from tripping vox.
It may be
talk the microphone to prevent background noise from
necessary to increase the VOX GAIN setting slightly
tripping the Collins KWM-2/2A into the transmit
after this ANTIVOX GAIN adjustment to compensate
for the ANTIVOX gain.
(3) Set meter switch (8) to ALC. Increase the
setting of the MIC GAIN control (4) to obtain S6
Do not use more VOX GAIN or ANTIVOX
average reading on voice.
GAIN than necessary to control vox operation.
(4) Leave the MIC GAIN control (4) as set in (3)
If the vox circuits transfer between words,
above. Leave the microphone in normal operating
increase the release time constant by turning the
position. Set the OFF-ON-NB-CAL switch (1) to
VOX TIME CONSTANT control (R43) (under
CAL, tune in the calibrate signal, and adjust the A.F.
top cover) clockwise. If less release time is
desired, turn the control counterclockwise
(5) Adjust the EXCITER TUNING control (6) for
an approximate 1,00-Hz beat note. If the vox
Table 3-1. Operating Control and Functions
Removes a.c. power from power supply.
Connects a.c. power to power supply.
Turns on accessory noise blanker when used.
Turns on 100-kHz crystal calibrator.
Grounds key line for continuous output in cw mode at full power.
Used for tuning.
Reduces pa screen voltage with series resistor, and produces cw
carrier for tune-up.
Selects LSB bfo crystal, and raises vfo frequency for LSB
Selects USB bfo crystal, and lowers the vfo frequency for USB
Selects USB bfo crystal, raises vfo frequency, and turns on tone
oscillator. Keyed tone is applied to balanced modulator
instead of voice signal.voice signal.
3 BAND (S2 through S8, S13)
Selects capacitors and crystals needed to tune transceiver to
desired 200-kHz band. S13 grounds a different pin on
J25 for each band for remote antenna selection.
MIC GAIN (R8, S10)
Controls audio amplifier gain for ssb operation, controls tone level
for cw operation.
A.F. GAIN (R92)
Controls receiving audio amplifier gain.
Controls all ganged slug tuned circuits in receiver and exciter
portions of transceiver.
P.A. TUNING (C150)
Resonates pa plate circuit to operating frequency.
Meter switch (S12)
Measures pa plate current by measuring pa cathode voltage
Measures pa grid current.
Shows ALC action by measuring cathode voltage changes at
transmitter IF amplifier V4A.
Adjusts power amplifier output impedance level to match
transmission line impedance for maximum power
R.F. GAIN (R84)
Controls gain of receiver-transmitter, RF amplifier, and receiving
IF amplifiers during receiving.
Zero set knob
Permits calibration of frequency dial.
Crystal board selector (S15)
Selects second bank of crystals for additional coverage and
(in KWM-2A only)
changes scale on BAND switch.
13 Vfo tuning dial
Selects the frequency to be added to the band frequency to
establish the transceiver operating frequency.
Inside cabinet VOX GAIN (R39)
Controls gain of vox amplifier for voice-controlled operation.
Inside cabinet VOX TIME CONSTANT (R43)
Controls held-in time of vox circuit
Inside cabinetNTIVOX GAIN (R45)
Controls level of antivox signal fed to vox circuit.