AMERITRON AL-80 - Page 4

TUNING PROCEDURE
1, Set the AL-80 front panel switches
as follows:
PWR - OFF
MODE - STDBY
METER SWITCH - PLATE VOLTAGE(V)
2* Insert the AC line cord into the ap¬
propriate outlet.
3. Turn the power switch "ONL The
plate voltage (V) should read approx¬
imately 2700 VDC. The grid (Ig) and
plate current (Ip) must read 0 MA.
The meter should light and the blower
on the rear must exhaust air,
4. Set the load control at 5,
5. Set the PLATE and BAND switches
to the band being used.
6. Tune your transceiver according to
the manufacturers instructions into a
50 ohm load. Reduce the drive to a
zero watt output point using the
drive level control provided on your
transceiver.
7. Move the AL-80 standby switch to the
operate position (OPT). Put your
transceiver in the "tune 1 1 position, the
red XMIT lamp on the AL-80 should
light and you should hear the relay
in the AL-80 "click". The XMIT lamp
should go on and off in step with
switching the transceiver into and out
of an active transmit (tune) mode.
If the XMIT lamp does not work pro¬
perly consult the trouble-shooting
section of the manual. The idle cur¬
rent (Ip) should be just under 150 ma.
with no drive when the XMIT light is
on.
8. With the transceiver on tune and the
AL-80 on OPT slowly advance the
transceiver drive control until (in the
Ip meter position) a reading of be¬
tween 150 and 300 ma. occurs.
9. Adjust the Plate control for maximum
output indication on the indicating
device ( SWR or wattmeter ) used.
The output power will be below 300
watts so low indications are normal
at this stage of tune-up.
10. Advance the drive until the Ip goes
to 350 ma. Adjust the loading and
Plate controls for maximum output.
It is a normal requirement to adjust
the Plate and. Load controls a few
times to get maximum output.
11. To prevent SSB flat-topping it is
necessary to load the AL-80 to the
maximum output possible with the
full drive (not to exceed 100 watts,
RF) of the transceiver.
The normal grid current of the AL-80
(Ig) is 100-150 ma* in a CW (single
tone) condition. On SSB and two-
tone tests the grid current will be
lower ■
On CW or RTTY tune the AL-80 to
maximum output at the output level
desired. Power is controlled by re¬
ducing the drive level. The proper
"load" setting changes for different
drive levels, rotating counter-clock¬
wise as the drive is reduced.
NOTES:
1. Do not operate the AL-80 into a load
presenting a VSWR greater than 2 to
1. The AL-80 may not function pro¬
perly and damage can result.
2, Grid currents (Ig) of over 200 ma.
should be avoided. Grid currents in
excess of 75 MA on SSB or 150 MA
on CW indicate excessive drive or
improper loading.