Larry Molitor wrote:
>Does anyone have any experience with a RCA 7213?
>I have one and thought it might be interesting
>to run it triode connected grounded-grid. Any
>pertinent thoughts would be appreciated.
It would be a terrible waste. Using a UHF tube like a 7213 on HF would
be like using a high-spirited racehorse to pull a cart. Worse than that,
in triode-connected grounded grid (TCGG) the poor beast would be dead in
I don't have the characteristic curves for a 7213, but most of the RF
drive in TCGG goes into the control grid, and modern ceramic-metal
tetrodes do not have the control-grid dissipation to handle that - and
in TCGG you can't even measure the screen and control grid currents
independently. If experience with 4CXC250s is anything to go by, TCGG is
a quick, sure way to ruin the tube.
The 7213 is rare and desirable for use at UHF, so why not trade it for
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
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