10
OPERATING HINTS
The Commander VHF-144 TUNE control is a high "Q" piston-type tuning capacitor with a 6:1
ratio vernier reduction drive. This control requires about 15 revolutions to tune the unit from
144 to 148 MHz.
Unless you have specified another band segment, the unit is factory tuned at 144.200, the na-
tional SSB calling frequency. If you use the Commander VHF-144 mainly for CW and SSB,
and after having tuned the unit to your antenna, you will be able to QSY up or down the CW/
SSB band segment without making any tuning adjustments. Unless someone changes these ad-
justments, it will not be necessary to retune the amplifier each time you operate it. Just turn the
unit on, wait for the green light and begin transmitting.
If you decide later to operate in the FM portion of the band, it is best done by tracking up the
band about 500 KHz at a time. To do this, key the exciter with low drive (5 watts or less), re-
tune INPUT for a peak in plate current (Ip), and readjust TUNE control for maximum output,
repeating this procedure as you move up the band. This is also useful if you happen to forget
where you left it tuned.
TYPICAL OPERATING CONDITIONS
DRIVE
GRID CURENT
PLATE CURENT
POWER OUTPUT
12.5 Watts
15 ma
400 ma
450 Watts
18.5 Watts
25 ma
500 ma
650 Watts
30 Watts
35 ma
600 ma
1000 Watts
Summary of Contents for COMMANDER VHF-144
Page 12: ...12 Commander VHF 144 HV Power Supply...
Page 13: ...13 AC Mains and Step Start Board VHF 144 13 5VAC...
Page 14: ...14 Control and Metering Board VHF 144...
Page 15: ...15 RF Deck VHF 144...
Page 16: ...16 Commander VHF 144 T R Relay Board...
Page 17: ...17 Commander VHF 144 Voltage Doubler Power Supply Board...
Page 20: ...20 Meter Board Cathode Fuse...
Page 21: ...21 Step Start Board AC Main Fuse 20A x 2 AC Interlock Step Start Relays x 4...
Page 22: ...22 Power Supply 470uF Capacitor 450 vdc x 8 HV Sense RF Output...
Page 23: ...23...
