On Sep 4, 2005, at 2:15 PM, Phil Clements wrote:
>
>> Most of the manuals that I have read give instructions that say to
>> reduce drive during tuneup. Do you agree with this procedure?
>
> I didn't, Rich, until 200-400 watt transceivers started hitting the
> market.
> My 3CX3000A7 and your 8171 would not be affected, but 400 watts into
> some of
> the popular smaller tubes might not be prudent.
An 8171 would show grid-I at 400w drive, but damage to the grid would
be unlikely. According to Eimac, a 3cx3000A7 would be slightly
under-driven at 400w.
> There can be no general rule
> to cover all circumstances, due to the increasing largeness of
> exciters, and
> increasing delicacy of some of the smaller newer vintage tubes. Most
> amp
> manufacturers did not consider anything over a 100 watt exciter when
> they
> wrote their manuals years ago. Interoperability is the name of the
> game as
> we upgrade our stations. When I started operating Harris RF-110's
> here, I
> just inserted a 30 db pad between my exciter and the Harris, so that
> when I
> do stupid things no damage is done. No-tune, 1.8-30 mhz, with idiot
> protection is a pretty nice way to go for an old man!
>
> (((73)))
> Phil Clements, K5PC
>
>
>
>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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