Hi Rob,
All current solid-state amplifiers use the ALC line as a part of their
protective subsystem. If an anomalous operating condition arises, the
amplifier will first reduce the drive power by pulling down the ALC line.
Next, it will switch itself off-line. The ALC line also serves to level the
amplifier output at the design rating (typically 1kW), to prevent overdrive
and the associated sharp increase in IMD.
The instruction manuals supplied with all the current solid-state amateur
amplifiers of which I am aware caution the user to connect and set up the
ALC correctly. Failure to do so will put the costly RF power devices at risk
of destruction.
Some commercial and military HF systems go a step further - if the ALC
feedback loop from the HPA to the exciter fails, the whole system shuts
down.
Cheers for now, 73,
Adam VA7OJ/AB4OJ
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Rob Atkinson, K5UJ
Sent: 18 August 2004 14:22
To: tentec@contesting.com
Subject: [TenTec] Ten Tec amps and ALC
This recent review of the IC7800 in eHam:
<<<Hi, my name is Marty, W3QK, and I just sent back my Orion, as when near
to a strong R.F. source, it locked up. I changed coax jumpers, VSWR ( which
was just fine ), and would have run an ALC line, but the Orion has no
external ALC. I am heading into purchasing an Icom 7800 and heard something
about the Front End having problems, but I think that the source didn't even
own one. I am visually impaired and run almost all my Icoms with computer
control. If there is anything that you dislike about it, please tell me. My
email is martyjp@comcast.net Otherwise, it will only be about 2 weeks till I
get mine. 73 and g.b. all of you. >>>
raises an interesting question (interesting to me at least).
Why do Ten Tec rigs lack an ALC jack and why do Ten Tec amps lack an ALC
input?
It has occurred to me when I have been driving my Centurion with nonTen Tec
exciters.
No problems as far as I can tell, however, it seems to be something Ten Tec
would want to include in their amps if they were interested in selling them
to hams running other than Ten Tec exciters.
Rob/K5UJ
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