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[Amps] Low Amplification Factor Triodes in Grounded Grid

To: "amps@contesting.com" <amps@contesting.com>
Subject: [Amps] Low Amplification Factor Triodes in Grounded Grid
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
Date: Thu, 12 Mar 2009 00:33:21 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
  Speaking of Bill Orr, I looked up an old article in the 15th edition of the 
"'Radio Handbook".
Actually two articles. One is a mathematical analysis of a 304TL in class C 
grounded grid. 
It has an amplification factor of 12.  It does take 200 watts drive to get a 
full gallon for that time.
200 watts drive for 1000 watts plate input power and 1025 watts output. 
   The second is a pratical one with pictures and everything. He also suggest 
bias voltage for
class B operation.  This was before the common 100 watt output transceivers 
were available.
Most hams in the 1950s had transmitters and receivers and a 35T in class C 
easily produced
200 watts output with 2kV on the plate. Or maybe a 75TL ( 1/4 of a 304TL).  At 
some point this 
amplifier exceeded the full gallon limit when a change to the FCC rules took 
into account 
the feed thru power in grounded grid amplifiers by requiring you to add up the 
plate input powers of
all the amplifier stages contributing power to the output to the antenna.
  You know, that may have been why Bill Orr published the article. You could 
get more than a kW to 
the antenna and still be within the 1kW plate input power limit.


73
Bill wa4lav
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