[Johnson] Question on a Valiant.

[Glen Zook]

Remember, on the Valiant, as on most "boat anchor"
transmitters, you are measuring cathode current and
not plate current.  Cathode current also includes the
screen current which must be subtracted to get true
plate current.  Each 6146 draws about 12 mA of screen
current.  Thus, you have to have 330 mA plus about 36
mA which is 366 mA at 681 volts for 225 watts input.

Also, remember that the 6146 is rated at a maximum of
67.5 watts input for AM operation.  For 3 of them, the
maximum input should not exceed 202.5 watts, and
running at this power level will greatly reduce the
longetivity of the tubes.  They are much happier at no
more than 60 watts input on AM and no one can tell the
difference at the other end.  However, the tubes will
last several times longer.

On CW, the maximum power input is 90 watts, or 270
watts for 3 tubes.  Again, cutting this back to about
75 watts input will greatly increase the tube life.

The power figures are directly from RCA as published
in various tables in advertisements in QST, etc.

Glen, K9STH


--- "Guy Olinger, K2AV" <k2av@contesting.com> wrote:

225 watts input with 330 mils would require 681 volts keydown.

=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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