Hello Phil
If you are using a GS23 at 3.2kV on 432, this confirm others peoples
findings that these russian tubes are quite good (the GS23 have
catalog peak anode spec of only 3.5kV).
Both GU84 and GS35 are good for what you want.
As you use the GS23 at higher anode voltage, also the GU84 may work.
You may find on www.krasnodar.online.ru/hamradio an amp
diagram for GU78/84 at 3 kV.
If the GU84 socket is a problem, then go for the GS35 as you may
directly conect its grid to the chassis.
Anyway, best is to use the cheapest and most available tube for you.
Happy New Year and Best Greetings to all,
Traian
Phil wrote:
> Ladies/Gents,
>
> Having now completed all other amplifier projects, I'm gathering thoughts
> (not to mention steam) towards putting a tube onto HF and I'd welcome any
> comments from the Group.
> Being in the coveted position of having a choice of tubes to use, I'm in
> something of a quandary (even after much thought) as to which would be
> 'best'. I plan to use the amplifier mainly for SSB service.
>
> I've got the following tubes currently available to me:
>
> 1. GS35b.
> 2. GU84b.
> 3. DOD006.
>
> It all rather depends on one's definition of 'best', I suppose. RF output
> wise, all three are likely to exceed UK licensing conditions, but would the
> GU84b produce the most with 2500W of anode dissipation available as opposed
> to 1500W or so for the other two? The GS35b would be easier to provide a PSU
> for as it is a triode but I believe that it would require a tuned circuit
> input. I have a socket for the GU84b so maybe that is the best way to go,
> and the input could possibly be a simple swamping resistor type. I've no
> socket for the DOD006, but the input requirements might be similar to the
> GU84b...?
>
> I have an existing 3.2Kv HV PSU which I use on my 432MHz GS23b amplifier -
> could this be used - current limits permitting - on the anode of the GU84b?
> The specifications suggest that 2.2Kv is the nominal voltage and 4Kv or so
> pulse. Would it be OK to use 3.2KV? If so, then maybe I should build a
> dedicated PSU for, say, 3.2KV at 2.5 amps....?
>
> Over the last year to two, I've gained much wisdom and guidance from
> 'Reflect-ees' and I would very much welcome anyone's thoughts and assistance
> in the choice of tube to use.
>
> A very Merry Christmas and a Happy & Peaceful 2002 to all.
>
> Phil
> G0HSS
>
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