If you really want to use the GLA-1000 on six meters consider
converting it as a monoband amplifier with EL-509s. Yes, the
509 is a sweep tube but Far Circuits has a replacement circuit
board, you should be able to add a tuned input and optimize
a monoband output circuit. You will need to take some care to
tame the tubes but as you point out sweep tubes can be made to
work and since you have the GLA-1000 about the only thing you
have to lose is your time if you can't make the conversion
work.
73,
... Joe, W4TV
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On Behalf Of david feldman
> Sent: Saturday, June 21, 2008 3:15 PM
> To: Harold Mandel; Carl; amps@contesting.com
> Subject: Re: [Amps] Tube suggestion needed - 6 and/or 2M
> ~500W level with800-1kv on plate?
>
>
>
> To take it back to the original interest - can the GLA1000 in
> this case be used as a mule to build a portable tube-based 6M
> amp (2M was something of an afterthought when I made the
> posting) of middling power level consistent with it's power
> supply. For this purpose, tubes are preferred over solid
> state, small is important, and self-contained is important.
> The GLA1000 is on hand, and from a project perspective, it
> seems interesting to me. What I've gathered so far is that
> there are probably no clearly-suitable tubes as a starting
> point (the 1KV plate voltage being the main barrier), and
> most likely the project will go no further (SB-200's
> converted to 6M are common enough and although a little
> larger, wouldn't have the new-design engineering challenges.)
>
> Thanks to everyone for the various insightful suggestions and
> discussion!
>
> Dave
>
> > Subject: RE: [Amps] Tube suggestion needed - 6 and/or 2M
> ~500W level
> > with800-1kv on plate?
> > Date: Sat, 21 Jun 2008 14:20:20 -0400
> > From: hmandel@barantelecom.com
> > To: km1h@jeremy.mv.com; wb0gaz@hotmail.com; amps@contesting.com
> >
> > {snip}
> > One idea Ive not tried is to take a regular 4CX250B and remove the
> > radiator (they are soldered on) and then make up your own
> solid block.
> > Or saw off one side of fins and replace with a brass plate.
> Then mount
> > a muffin fan on top of the cabinet to draw out some heat thru the
> > remaining fins while another fan blows on the heat sink. {snip}
> >
> > Doesn't all this sound cost-inefficient, somewhat?
> >
> > Are you in desperate straits to get this particular
> > machine configured with so irregular a design?
> >
> > My next question is directed towards the
> > RF Circulating Current model, as yet-unbuilt,
> > that extensive modifications in an untried
> > cavity will produce......
> >
> > However, science for the benefit of learning
> > is fruitful at any expense.
> >
> > "The operation was a success, but the patient died."
> >
> > Good hunting, "hals und beinbruch!"
> >
> > Harold Mandel
> > W4HBM
>
> _________________________________________________________________
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