On Sep 9, 2005, at 7:27 AM, John T. M. Lyles wrote:
> Chris
> The Continental 816R series FM broadcast rig has a variant with
> 4CX15,000A. I assume you didn't mean 4CX1500A. At their website
> http://www.contelec.com/ go to support, then look for manuals and
> download the training manual for this. You might find the screen
> power supply details there. CEC uses the trick of grounding the
> screen and putting negative screen V return and postive grid bias
> return on the filament of the tube, with an isolated filament
> transformer. It is conventional grid driven tetrode operation, but
> better stability via the excellent screen grid grounding for RF.
Not only is the stability better, it solves the problem of trying to
build a screen bypass cap that will handle c. 25A at 28MHz.
>
> Otherwise, the screen power supply for such tetrodes (and the
> 4CX10,000 and 4CX20,000 series) is quite conventional, most use a LC
> filter, single phase power supply (or three phase) and FWbridge
> rectifier. Most are not regulated in the broadcast FM rigs (class C)
> and just have a stiff bleeder resistance across the output of the PS.
>
> 73
> John
> K5PRO
>
>>
>> Message: 2
>> Date: Thu, 8 Sep 2005 12:27:20 -0700
>> From: "Chris" <rfcrazy@cox.net>
>> Subject: [Amps] Screen Supply
>> To: <amps@contesting.com>
>> Message-ID: <000001c5b4ab$55245960$0301a8c0@chriszfw9zp3ay>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Hello,
>>
>>
>>
>> Can anyone help me with a schematic for a screen supply for a
>> 4cx15000a? Or
>> point me in a direction in which I may locate one? I need a model
>> reference.
>>
>>
>>
>> Thank you :-)
>>
>>
>>
>> Chris
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>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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