Geoff
With so many combinations of rig and amplifier a 'standard' would be good,
(the Collins ALC started it all I understand) but in its absence each
operator needs to make provision for their own station protection.
With the advent of solid state amplifiers there was a chance to make a new
standard to help us all, perhaps someone knows if this was taken up . It
would be good to know how folks have covered themselves with various
rig/amplifier combinations and I wonder how the Elecraft linears will do
this. I see the SPE linear has 3 stages of protection for instance: SIMPLE
= audible alarm, SERIOUS = switch to standby and FATAL = complete shutdown,
but these do not shutdown the driving transmitter as far as I can see.
After all, running barefoot is better than nothing in a contest, so,
shutting down the transmitter is not always desirable.
David
G3UNA
----- Original Message -----
From: "Geoffrey Mackenzie-Kennedy" <[EMAIL PROTECTED]>
To: "David Cutter" <[EMAIL PROTECTED]>
Cc: "Elecraft Discussion List" <elecraft@mailman.qth.net>
Sent: Tuesday, December 04, 2007 12:46 PM
Subject: Re: [Elecraft] linear amp shutdown (was ALC)
From: David Cutter G3UNA
I take your point entirely which is why I said
"ALC is an analog signal for gradually reducing drive, which
might not be appropriate for shutdown."
Shutdown for me is for protection against gross overload and for this
another signal might be more appropriate. Since many users do not
connect ALC, some other signal for protection should/could be provided.
The problem yet again is that users might still ignore what the
manufacturer offers, so, the amplifier must protect itself.
-------------------------------------------------------------------
David,
It has always been my understanding that normal and good practice is for a
shutdown system to actually *shutdown* the entire transmitter affected in
the event of gross overload / failure, e.g. *abnormal* VSWR, cooling
system failure etc. A system which protects the amplifier only could
still result in damage to the exciter / driver under some circumstances of
gross overload / failure, for example when using my K2/100 a while back
during some contest wind toppled a large pine across the antenna in use,
the KAT100 sparkled and both the KPA100 and K2 were damaged. My K2/100 is
now protected by the total shutdown system used with my other rigs,
something that I should have done before ever using the K2/100 at this
location.
I take your point that the amplifier should be able to protect itself if
people ignore what is offered.
73,
Geoff
GM4ESD
.
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