[Amps] CW and High Voltage

[R.Measures]

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