[Amps] Alpha &&DX Conversion

[Carl]

Hams need more headroom to make up for inadequate cooling (Oh my. I dont 
like all that noise, how can I quiet it down?) and lack of understanding how 
to tune a tube with a fussy grid. Mindless QSY's without watching the grid 
meter dont help.

Carl
KM1H



----- Original Message ----- 
From: "Paul Christensen" <w9ac at arrl.net>
To: <amps at contesting.com>
Sent: Wednesday, September 05, 2012 6:04 PM
Subject: Re: [Amps] Alpha &&DX Conversion


> Vic,
>
> Valid point but the FCC- registered efficiency was 58% and is typical of 
> an FM broadcast GG design.  The AEL FM 2.5K is a GG design and not 
> tetrode-based as were the more common FM broadcast transmitters.
>
> Paul, W9AC
>
> ----- Original Message ----- 
> From: "Vic K2VCO" <k2vco.vic at gmail.com>
> To: <amps at contesting.com>
> Sent: Wednesday, September 05, 2012 5:57 PM
> Subject: Re: [Amps] Alpha &&DX Conversion
>
>
>> Paul,
>>
>> Don't forget that the FM transmitter was probably running class-C which 
>> might be 75% efficient compared to the 60% or so available in class 
>> AB1/2.
>>
>> On 9/5/2012 2:48 PM, Paul Christensen wrote:
>>>> "I will tell you why i run a 2 tuber, you put in 25 watts in and do 
>>>> 1500 easy not
>>>> push a one tuber to do 1500 out. it all comes down to what you can 
>>>> afford. bill 73"
>>>
>>> This may be an interesting point of reference.  During my college years, 
>>> I worked at a
>>> 3KW FM station in Rockford, IL as its chief engineer.  The transmitter 
>>> was an AEL
>>> FM-2.5K (FCC type accepted to 2.5KW output) and used a single 8877 to 
>>> produce
>>> 2500-watts output at 104.9 MHz.  All day long, every day, 365 days a 
>>> year.   A
>>> three-bay circularly polarized antenna brought ERP to 3KW.
>>>
>>> If a 77Dx is running intermittent amateur-class service but under high 
>>> duty-cycle modes
>>> like RTTY at 1500-watts output (the U.S. legal limit, for example), I 
>>> think its
>>> reasonable to assume that a 8877 is already operating with sufficient 
>>> headroom of
>>> roughly 1KW.   For what purpose do any of us need more than 1KW of 
>>> headroom from our
>>> vacuum tubes when producing 1.5KW?
>>>
>>> Paul, W9AC _______________________________________________ Amps mailing 
>>> list
>>> Amps at contesting.com http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> -- 
>> Vic, K2VCO
>> Fresno CA
>> http://www.qsl.net/k2vco/
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
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