Tubes with 12 or 28 v Plates?

Wed Jan 5 17:56:56 EST 2000

Except for maybe a couple of watts, none. Even that is from a couple of
car-radio type Low plate voltage audio output tube types....
Simple AM/CW tube transmitter designs are found in the ARRL Handbook up to
the 60's, as well as in issues of all the amateur magazines - QST, Ham
Radio, 73 and CQ. The RSGB handbook from those years is a good resource, as
well as the Editors and Engineers Radio Handbook.

If you want to build a tube transmitter to work from 12 or 24 VDC, you'll
have to build or buy a DC-to-DC converter to get the plate voltage for any
regular, non car-radio type tube of which very few types were made -
transistors came out before they became very popular.

73, Meir WF2U

P.S. You can take a few tube curves and try to figure out the impedance and
plate current under low voltage conditions. You can also determine the
curves empirically
by  measuring the parameters of the tube in a test setup, with the plate
voltage you want to use and vary the bias. The plate current will be
indicative of the power output capability and the plate current/grid current
will roughly give you the device gain.

-----Original Message-----
From:   Boat Anchor Owners and Collectors List
Sent:   Wednesday, January 05, 2000 11:26 AM
Subject:        Tubes with 12 or 28 v Plates?

Can anyone tell me what tubes are useful in a TX
application that are also efficient with 12 or 28vdc

Cost and availability?

Simple AM/CW HF TX designs?

- Thanks! & 73, DavidC  K1YP


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