2 (Rich) wrote:
>
> // I do not have a manual. please quote Mr, Rauch's reasonable
> statements.
Actually, I found the AL80B manual on the Ameritron web site
(http://www.ameritron.com). Here is an excerpt from the tune-up discussion.
Although the 400 MA figure is not mentioned (but see below), it's clear that the
intent is to tune up for peak conditions and then reduce the drive for CW.
------------------------
"Increase the exciter drive power (if the ALC is not connected) until 180 mA of
grid current is indicated. Adjust the "LOAD" and "PLATE" controls for maximum RF
output power. The grid current should not be allowed to go above 200 mA at this
stage. The plate current should not be allowed to exceed 600 milliamperes during
brief periods of tuning (15 seconds)."
"For CW operation, the output power should be reduced with the "ALC SET" control
until the rated output power of 800 watts is obtained. The "LOAD" control should
be adjusted until minimum plate current is obtained without dropping below 800
watts. The exciter's power can be reduced until the multimeter shows a slight
upward flicker with the "MULTIMETER" switch in the ALC position if the ALC is
used."
"For SSB operation, the "ALC SET" should be adjusted to allow 200 mA of grid
current (near the 20 volt marking). The exciter should be set to produce maximum
output power (not to exceed 100 watts of peak power). Next the amplifier's
"LOAD" and "PLATE" controls are adjusted for maximum power output on the
internal peak reading RF wattmeter with either a two-tone generator or sustained
"HEL-L-L-L-L-O" driving the exciter. The "ALC SET" control should then be
reduced until the peak power output is slightly lowered. Finally the exciter's
audio gain or output power is adjusted until the multimeter "ALC" position
indicates the desired ALC level. This setting should normally allow around 150
mA grid current on a steady carrier or "whistle"."
---------------------------
Finally, from the discussion of the ALC Set adjustment:
----------------------------
"The "LOAD" control setting determines the maximum plate current and output
power for a given grid current. Never exceed 600 mA of short duty cycle (or 400
mA of long duty cycle) plate current. Never exceed 200 mA of operating grid
current."
----------------------------
73,
Vic, K2VCO
Fresno CA
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