On May 29, 2006, at 1:06 PM, PA3DUV wrote:
> Rich,
>
> For the single bander they might get away with it.
> But I've seen multiband designs of the same origin which catched
> fire due to oscillation of the amp.
Indeed, Dick. For an 8171, the problem is typically oscillation at
c. 70MHz, so multi-band or single-band makes no difference. As I see
it, grounding the screen collet with 8, Cu straps is something to
avoid if one is trying to build a VHF oscillator using the 8171.
>
> Cheers, Dick
> PA3DUV
>
> ----- Original Message ----- From: "R L Measures" <r@somis.org>
> To: "PA3DUV" <pa3duv@planet.nl>
> Cc: <amps@contesting.com>
> Sent: Monday, May 29, 2006 10:02 PM
> Subject: Re: [Amps] twin 4CX-10 000D amplifier: multiple tubes
>
>
>> Not directly-grounding the screen collet of a 4cx10,000D is an
>> invitation to a squirrel invasion.
>>
>> On May 28, 2006, at 1:06 PM, PA3DUV wrote:
>>
>>> Gentlemen,
>>>
>>> For those interested in the design of HF power amplifiers this
>>> web page might be of interest:
>>>
>>> http://66.249.93.104/translate_c?
>>> hl=en&ie=UTF-8&oe=UTF-8&langpair=ja %7Cen&u=http://www.iizuka-
>>> net.ne.jp/~bear-el/10000d-2&prev=/ language_tools
>>>
>>> or without the translator:
>>>
>>> http://ns.iizuka-net.ne.jp/~bear-el/10000d-2/
>>>
>>> This single band 7 MHz amp for amateur usage is conservatively
>>> rated at 20 kW output. Exciter is an Icom IC7800.
>>> According to the builder of the amp is does 20 kW out without
>>> abnormal blower noise levels or a burning smell from the RF deck.
>>> A 30 kVA 3 phase power supply is used, generating an unloaded B+
>>> of 8 kV DC.
>>>
>>> Cheers, Dick
>>> PA3DUV
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> R L MEASURES, AG6K. 805-386-3734
>> r@somis.org
>>
>>
>
>
R L MEASURES, AG6K. 805-386-3734
r@somis.org
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