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8.
ALC Connection
ALC voltage is available at the terminal marked ALC (RCA phono jack) on the right lower
corner of the rear panel. Negative maximum DC voltage of ten volts (-10V) is produced at
this terminal when the amplifier is fully driven. This voltage is adjustable with the ALC
ADJ. knob located above the ALC jack. Setting ALC voltage properly fed back to the
transceiver, we recommend you to keep the maximum output power constant or hold the
power at a certain level. Also ALC is useful in avoiding your SSB signal from being
distorted when overdriven. Depending upon the manufacturer of the transceiver, the
suitable ALC voltage differs. ICOM may need 0~-4V, and Yaesu may need 0~-5V range.
Kenwood may need -6~-8V maximum. Check your transceiver manual.
8-1
Prepare an ALC control cable using RCA plug supplied in the package. Solder a
single wire or (more preferably) a shielded single wire to the center pin of RCA
plug and solder the shield braid to the outer side of the plug. Connect the control
cable to the "ALC (or EXTERNAL ALC)" jack of the transceiver. External ALC
input is sometimes available at one of the pins of the "ACC" socket of the
transceiver as well.
8-2
At first, turn ALC ADJ full clockwise. Drive the amplifier in CW/RTTY mode to
full output power. Then turn the ALC ADJ counter-clockwise. Observe the
SWR/Power meter at the output, (or Pf of the multimeter). Stop turning the ALC
ADJ at the point the power starts to decrease. Or if you wish to further reduce
the power, keep turning ALC ADJ until the desired level is achieved. If you
further try to increase the drive power you will now see the output power become
rather saturated, from these adjustments.
(Maximum ALC voltage produced is -10V when the amplifier output power is
over 200W.)
REAR PANEL ALC POT.
A A A A C C C C
MAX
T T T T o o o o T T T T r r r r a a a a n n n n s s s s c c c c e e e e i i i i v v v v e e e e r r r r
12
A A A A L L L L C C C C
A A A A D D D D J J J J
MIN
S S S S T T T T B B B B Y Y Y Y A A A A L L L L C C C C
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