Yes, but at the same time, your also adding Cg. Which is usually minute with
one tube but begins to add up with several.
Mike(y)
W3SLK
----- Original Message -----
From: measures <2@vc.net>
To: Steve Thompson <rfamps@ic24.net>; AMPS <amps@contesting.com>
Sent: Wednesday, September 20, 2000 12:40 PM
Subject: Re: [AMPS] Some tube questions...conversion to H2O cooling
>
> >
> >
> >-----Original Message-----
> >From: Bob Duckworth <wb4mnf@atl.org>
> >To: amps@contesting.com <amps@contesting.com>
To: <amps@contesting.com>
> >Date: 19 September 2000 15:25
> >Subject: [AMPS] Some tube questions...conversion to H2O cooling
> >
> >
> >>
> >>I'm curious.
> >>How do I figure out how much current I can squeeze through a tube.
> >>Lets use the 4cx250FG for example.
> >>
> >>4cx250FG
> >>It's heater draws 14 watts.
> >>The max plate voltage is 2KV and it's rated
> >>as a 500W input tube.
> >>Plate dissapation is 250W.
> >>
> >>If I can keep it cool, how much plate current can I expect to run
> >>before there are not enough electrons coming off the heater?
> >
> >
> >The most I've ever known of is running them in real cut off class C with
> >about 400mA of anode current key down. The user had a source of really
good
> >ones that took 3kV in cutoff and 2.7kV key down. Output from a pair was
in
> >the 1.5kw region, and they lasted around a year of regular skeds. For EME
or
> >MS cw use, transmit duty is about 60%, and there's 50% rx time so the
anode
> >dissipation isn't compromised.
> >
> >At $10 each, I'd stick to 2kV, 250mA and just put more in parallel.
> >
> good idea, Steve. Paralleling tubes is a lot easier than most builders
> think. As RL decreases, more Tune-C is naturally needed to maintain a Q
> of c. 10.
>
> cheers
>
> - Rich..., 805.386.3734, www.vcnet.com/measures.
> end
>
>
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