[Amps] History of Grounded Grid Amplfiers

[RCM]

> On Dec 15, 2020, at 08:30, Rob Atkinson <ranchorobbo at gmail.com> wrote:
> 
> 
> These are class C grid driven transmitters, very different from a
> grounded grid, cathode driven class AB amplifier which, because it is
> cathode driven does not require a neutralizing circuit.  I believe
> Bill Orr developed the grounded grid cathode driven linear amplifier
> when he was with Eimac, and covered the design in a 1969 Ham Radio
> Magazine article using the zero bias 3-500Z.     I imagine he worked
> out the metering.
> 
> With such an amplifier, there's a lot going on around the cathode:  It
> has to be lit up, biased, metered, and driven with RF.    It takes a
> lot more drive, but manufacturers liked it because the cathode Z was
> easy to match, or with tube exciters they didn't even bother, and no
> Cn circuit was needed.  Band switching was easy.
> 

I think 1969 is a little late to the dance.

I have a 1959 Bill Orr handbook with a GG 304TL.

Same book has my first home brew with 837’s and Central Electronics 20A.

Also, four 811’s. A 4-250.

A 1956 ARRL  handbook has four 811’s

The Collins 30L1  from the 1950’s is GG 811’s

When building my 3-500Z box, in the 1980’s, I had a couple of questions.

I called Eimac, Bill answered the phone. 45 minutes later…..

Go here and mouse down to “Radio” 

Fill a hard drive. ARRL 1936, 1942, Bill’s 1959 Handbooks.
http://www.tubebooks.org/technical_books_online.htm <http://www.tubebooks.org/technical_books_online.htm>

Bob
K2RK