Receiver Tuning

TM 11-5820-544-12

NOTE

The crystal calibrator will also be heard at

NOTE

dial settings 55 and 155 when the OFF-

Before setting the vfo tuning (13), calibrate the

vfo by setting the OFF-ON-NB-CAL switch (1)

ON-NB-CAL switch (1) is at CAL. Ignore

to CAL and zero-beating the calibration signal at

these responses.

the 0, 100, or 200 dial marking, whichever is

CAUTION

closest to the desired operating frequency. Adjust

Do not keep the Collins KWM-2/2A plate

the dial hairline so that it is directly over the dial

current above 230 ma for longer than 30

0, 100, 200 marking at zero beat. Set the OFF-

seconds at one time.

If the operating

ON-NB-CAL switch (1) to ON.

frequency is changed, recheck turning and

3-11. Receiver Tuning

loading adjustments. Readjust if necessary.

3-12. Transmitter Tuning

(fig. 34)

a. Set the OFF-ON-NB-CAL switch (1, fig. 3-4) to

a. General

ON (table 3-1).

(1) Set up for receive function as in paragraph 3-10.

b. Set the EMISSION switch (2) to the desired

(2) Set the EMISSION switch (2) to TUNE.

side-band (USB or LSB) position. Set the BAND switch

(3) Set the P.A. TUNING control (7) to the white

(3) to the desired band. On the Collins KWM-2A, set

portion of the dial indicating the desired band (for

the crystal board selector (12) so that a desired set of

amateur operation). If the transceiver is being operated

bands appears in the window.

outside the amateur bands, ignore the amateur band

c. Set the MIC GAIN control (4) fully

markings on the dial scale, and set the control according

counterclockwise. Set the R.F. GAIN control (10) fully

to the logging scale charts (fig. 3-5).

clockwise.

(4) Set the meter switch (8) to PLATE.

d Set the VOX GAIN control (R39) (under top

(5) Advance the MIC GAIN control (4) fully

cover) fully counterclockwise.

clockwise, and rock the EXCITER TUNING control (6)

e. Set the ANTIVOX GAIN control (R45) (under

until maximum plate current is obtained.

top cover) fully counterclockwise.

(6) IMMEDIATELY dip the plate current with the

f Adjust the A.E. GAIN control (5) until some

P.A. TUNING control (7).

receiver noise is heard in the speaker.

(7) Return the MIC GAIN control (4) fully

g Adjust the EXCITER TUNING control (6) to the

counterclockwise.

white portion of the scale indicating the desired band.

(8) Set the meter switch (8) to GRID.

Rock this control slightly to peak the receiver noise

(9) Advance the MIC GAIN control (4) until grid

output. The transceiver is now ready to receive and the

current is obtained.

selected 200-kHz band may be tuned with the tuning

(10) Rock the EXCITER TUNING control (6) to

control. The operating frequency can be determined by

obtain a peak in grid current indication.

adding the dial reading to the BAND switch (3) setting.

(11) Turn the MIC GAIN to OFF.

h Turn the OFF-ON-NB-CAL switch (1) to CAL.

(12) Set the EMISSION switch (2) to LOCK.

Tune the dial to the nearest 100-kHz point (0, 100, or

(13) Advance the MIC GAIN (4) to provide a grid

200), and decrease the R.F. GAIN control (10) as

current reading of approximately 1/3 scale.

necessary for a comfortable listening level. Adjust the

(14) Set the meter switch (8) to PLATE.

tuning until the calibrate signal is zero beat. When the

(15) Alternately dip plate current with the P.A.

calibrate signal is zero beat in the receiver, set the

TUNING Control (7), and adjust loading with

hairline on the 100 kHz mark with the zero beat knob

the INCR LOAD control (9) until plate current

(11). Set the OFF-ON-NB-CAL switch (1) to ON and

is 230-ma at the dip. When operating the

tune the dial to the desired portion of the 200 kHz band

transceiver with a linear amplifier, load to only

selected.

200-ma.

(16) Set the EMISSION switch (2) to LSB, USB, or

WARNING

During amateur operation. DO NOT operate

CW.

the transmit circuits while the transceiver is

b. Single-Sideband Operation.

tuned to receive outside the band in use. The

(1) Set up receiver operation and transmitter

transmit frequency is always locked to the

operation completely as in paragraph 3-11 and a above.

receive frequency. Return tuning to within

the band before transmitting.

Change 1 3-7