[AMPS] Some tube questions...conversion to H2O cooling

[Steve Thompson]

-----Original Message-----
From: Mike Sawyer <kc4slk@csrlink.net>
To: measures <2@vc.net>; Steve Thompson <rfamps@ic24.net>; AMPS
<amps@contesting.com>
Date: 20 September 2000 21:38
Subject: Re: [AMPS] Some tube questions...conversion to H2O cooling


>
>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
For hf use, you could try a swamping resistor per pair, and then split the
drive with wideband transformers.

Steve

>----- 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>
>> >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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>
>
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