How to Tune the AL-811H Ameritron Amp

Flip the ̶0;Power̶1; switch to the ̶0;Off̶1; position, the ̶0;XMT̶1; switch to the ̶0;STBY̶1; position and the ̶0;Meter̶1; switch to the ̶0;HV̶1; position. Plug the power cord into a nearby electrical outlet.

Flip the ̶0;Power̶1; switch to the ̶0;On̶1; position. The meter lamps will illuminate and the cooling fan will run. The 2,000 volt scale on the multimeter should read between 1,700 and 1,800 volts.

Tune the radio̵7;s exciter to read 50 ohms per the manufacturer̵7;s instructions. Turn the exciter drive all the way down once it is tuned.

Flip the amplifier bandswitch to the same band as the exciter on the radio. If the exciter is set to the 1.80 MHz band, flip the amplifier switchband to 1.80 MHz. Turn the ̶0;Plate̶1; and ̶0;Load̶1; control dials to the appropriate range for the band selected. The appropriate ranges are as follows:

MHz Plate Load

1.80 1 ½ 6 ½
1.90 3 7/12
3.5 5 2
3.7 6 3
4.0 6 ½ 5 ½
7.0 8 3
7.3 8 3 ½
10.1 7 ½ 0
14.0 9 3
18.1 9 2 ½
21.0 9 ½ 4
24.9 9 ½ 4 ½
28.5 9 ½ 5

Flip the ̶0;Meter̶1; switch to the ̶0;Ip̶1; position. The 750mA scale should read ̶0;0.̶1;

Flip the ̶0;XMT̶1; switch to the ̶0;OPR̶1; position.

Key the exciter per the manufacturer̵7;s instructions. Keying the exciter is the process of activating it. The ̶0;Transmit̶1; light will illuminate. The plate current on the 750mA scale should read ̶0;125mA.̶1;

Increase the drive to read full exciter power, but do not exceed 80 watts. Increase the drive until the grid current registers 200mA. Turn the ̶0;Plate̶1; and ̶0;Load̶1; control dials until the needle is stabilized.

Reduce the drive until the radio manufacturer̵7;s recommended output levels are reached.