[ICOM] AMP INTERFACE TO 756 PRO II

[Adam Farson]

Dan, Malcolm,

Just had a look at the ALS-600 Meter/ALC board schematic. The ALC voltage is
derived from the forward and reflected power voltages produced by the
reflectometer on the SWR Detect board.

The significance of this is that the ALC not only controls the drive so as
to level the amplifier output at a preset value, thus preventing overdrive.
The ALC also protects the amplifier by reducing the drive in the event of a
load mismatch. Thus, proper connection and calibration of the ALC is
absolutely mandatory when using a solid-state amplifier. The ALC is the
amplifier's first line of defence.

There is a discussion of ALC in my solid-state amplifier article:

http://www.qsl.net/ab4oj/quadra/sshfamp.html#11

Some amplifiers also reduce drive from the exciter (via the ALC line) in the
event that some other abnormal condition arises, such as PA
over-temperature.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


Scanned by WinProxy
http://www.Ositis.com/