[AMPS] Triode conected Tetrodes

Arthur Moe kb7ww@chatusa.com
Tue, 07 Jan 1997 12:30:42 -0800

While looking through the ARRL hand book (1979) I came across an
article for an 833a tri band amplifier. In the first part of the
article the author says 

"Pi-network value are given for various surplus tubes: 4-400A, 4-250A,
304TH and 833A.


The power tube is used in the grounded-cathode configuration. If the
tube to be used is a tetrode, the screen and grid should be tied 
together to simulate a triode. The 0.01-u F disk capacitors from each
cathode terminal to ground provide a low-impedance rf path,
effectively by-passing the cathode to ground. Grid voltage is 
developed across a low resistance, R1, which coincidentally maintains
a constant load impedance for the exciter and prevents instability."

Now for some questions:

Can other tetrodes be used the same way? i.e. 4-1000, 4CX3000,

How do you determine Bias voltage for a triode connected tetrode? 

In what range would you except the IMD to be?

Is there any problems with this type of amplifier?

Thanks for any and all answers.


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