Section III. OPERATION - TM-11-5820-554-120022

TM 11-5920-554-12

3-8. Initial Checks

them, and use chokes in series with the leads from the

(fig. 3-4)

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-

regulator.

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.

WARNING

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-

CAUTION

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

CAUTION

3-136.

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

3-10.SelectingCollinsKWM-2/2A

the BAND switch to (3) to the proper position for

Operating Frequency

the installed crystal.

CAUTION

NOTE

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

exceed 2.0:1.

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

bands.

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

transceiver.

(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