[ICOM] AMP INTERFACE TO 756 PRO II

[Malcolm Ringel]

QSL, Adam and thanks for the info. I was due to do something right, even if 
I didn't know precisely why, H I. As they say, even a blind hog will find an 
acorn from time to time.
So, the ALC line will stay in place.
73,
Malcolm Ringel
ARS K3KZ
Saint Michaels, MD

----- Original Message ----- 
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Tuesday, June 14, 2005 8:45 PM
Subject: RE: [ICOM] AMP INTERFACE TO 756 PRO II


> 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
>
>
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