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4.5.4 VFO Sideband Frequency Shift Adjustment.


Do not make this adjustmcnt unless switching from one sideband to the other makes readjustment of tuning ctial necessary to keep output signal froll) shifting.

Set the EMISSION switch to LSB and the OFF-ON-NB-CAL switch to CAL, and turn the main tuning dial to zero beat with the calibrate signal at 3.7 ISItIz. Without further movement of the main tuning dial, switch the EMISSION sWitch to USB and adjust thc vfo capacitor (C308) to obtain zero beat.

4.5.5 Carrier Balance (Null) Adjusment

  1. Set BAND switch to 3.6 and tuning dial to 100.

  2. Set Ei\flSSION switch to LSB, and turn MIC GAIN full counterclockwise until it clicks. Key KWM-2/2A by turning VOX GAIN coun-terclockwise until it clicks or by grounding push-to-talk (ptt) line at jack J16.

  3. Loosly couple receiver antenna lead to dummy load, and peak EXCITER TUNING and P. A. TUNING to obtain a midscalc reading on receiver S-meter.

  4. Adjust CARRIER BAL potentiometer R15 and trimmer capacitor C9 for minimum indication on receiver S-meter. These adjustnients interact, so adjust first one and then the other until neither produces any further decrease in S-metcr indication.

  5. Switch EMISSION switch back nll(l forth between USB and LSB to see that the carrier suppression is about the same for either sideband. If it is not, repeat step d until carrier suppression is about equal for both sidebands.

  6. Remove receiver antenna lead from near dummy load, and remove short from PT'I' linc.

4.5.6 ALC Zero Adjustment.

  1. Sct EMISSION switch to TUNE: position. 'I'une and load transmittcr to 14.1 MHz. Set EMISSION Switch to USB.

  1. Set MIC GAIN control to minimum, and set metcr switch to ALC position. Short ptt jack Jl6 to ground.

  2. Adjust ALC ZERO potentiometer (inside cabinet) until metcr indicates zero. Remove ptt short.

4.5.7 First Mixer Balance Adjustment

  1. Set BAND switch to 21.0 and tuning dial to 0. Tune and load KWM-2/2A into dummy load, then set EMISSION switch to LSB and MIC GAIN to counterclockwise limit until switch clicks.

  2. Loosely couple receiver antenna lead to dummy load. Tune receiver across 21.455 MHz until signal is heard.

  3. Adjust mixer balance potentiometer R24 and trimmer capacitor C21 for minimum signal. These adjustments interact so adjust first one and then the other until neither produces any further decrease in output.

4.5.8 S-Meter Zero Adjustment

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  • Set fSAND switch to 14.2 and tuning tial to 100. Connect out,uut ot l00-kHz crystal calibrator in test receiver to 50-ohm dummy load. Peak KWM-2/2A EXCITER TUNING for maximum K WM-2/2A S-meter indication. Set RF GAIN to clockwise limit, and turn off 100-kHz crystal calibrator.

  • Short RCVR AN'I'. jack J2 to ground. Adjust S METER ZERO potentiometer R121 for zero indication on S-metcr.

    4.5.9 Crystal Calibrator Adjustment

    1. Tunc KWM-2/2A to zero beat with carrier of station WWV at 15.0 MHz at a time when station WWV is not transmitting a tone.

    2. Set OFF-ON-NB-CAL switch to CAL. Adjust CAL. ADJUST trimmer C76 (inside cabinet on chassis) for zero beat calibration signal.

    4.5.10 VFO End-Point Adjustment

    With the BAND switch set to 3.6 the KWM-2/2A should be in zero beat with the calibrator signal at 3600 KHz (0 on the KWM-2/2A dial)

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