A while back I spoke to Alpha about ALC in connection with some Yaesu issues
(thump and loss of ALC control in an early MP--Yaesu issued a fix). They
strongly recommended not using an ALC loop unless you have a TX capable of
more than 100W, in which case the ALC should be set up for amp protection in
the event of fumble fingers setting the transceiver for 200W out. Their
feeling was that ALC was useful for protection only, and if you were set up
so that you were routinely bumping up the ALC line when keying or with an
SSB signal, you were not set up correctly and were probably degrading
linearity. Of course if you have an amp with a damage level not far above
the normal operating drive, you need the ALC. A couple of 8877 amps without
a fast overdrive trip come to mind.
Bob W2WG
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of K4IA@aol.com
Sent: Tuesday, July 18, 2006 7:53 AM
To: tentec@contesting.com
Subject: Re: [TenTec] Fwd: Is Orion really worth it? Given
thepublishedproblems?
Key Clicks? I was running the Orion at 50 watts putting out 700 watts from
an amplifier capable of 1300 so I doubt the clicks were a drive issue.
There
has been thread on this topic here before and the clicks are real. The
good
news is you can adjust the rise time but there was also a discussion of how
the rise time settings were neither accurate nor linear making such
adjustments guesswork.
As for what the ALC controls (amp or exciter), I guess it is a
chicken-and-the-egg thing. IF there was an ALC loop back to the exciter
then the ALC
would control the exciter but since the drive determines the ALC level, I
suppose
you could say the exciter controls. Who cares? There is no ALC interface
on the Orion and that is a substantial problem with amplifiers that do make
good use of ALC. For example, the QUADRA uses the ALC circuit to
automatically
reduce power output for tuning
k4ia
Craig "Buck" Enjoying his Orion in
Fredericksburg, Virginia USA
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