13
OPERATING HINTS
The Commander II 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. No pointer or logging scale is provided.
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 II 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 adjustments,
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.
The scale for the TUNE control on the front panel is correct in that
clockwise is increasing frequency and counter-clockwise is decreasing frequency.
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
