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[Amps] I am just wondering ...

To: amps <>
Subject: [Amps] I am just wondering ...
From: Ron Youvan <>
Date: Tue, 27 Jun 2017 16:19:32 -0400
List-post: <>
  Hi all:

  Have you ever heard of a HAM amplifier that feeds the reverse power
(reflected power) value back to the exciter through the ALC signal to
lower the drive under high reverse power conditions like when the wrong
antenna is being fed and other such maladjustments?  Which ones?

  I think I found one, but the information is a bit confusing.


  In part:

 the ALC output sends the DC control voltage to the IF stages of the
exciter which is thus gain-controlled. This voltage is proportional to the amplifier power output but negative-going that means that the higher
the voltage, the lower the exciter output. The reason is next.

 the signal (forward-power) is sent by the reflectometer to the
controller that derives the ALC voltage. As soon as a anomalous
conditions is met (e.g. the reflectometer reports a load mismatch), the
controller develops a positive ALC voltage to reduce the drive to a safe
level.  At this instant the exciter reduces its RF output power.

  Are there any more?

Many broadcast transmitters work this way, but the exciter matches the power amplifier in most cases. (they were designed to work together)
  Ron  KA4INM - Youvan's corollary:
                Every action results in unwanted side effects.

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