> >Sorry, brain slipped out of gear. Meant Series L.
> // More tubes in parallel proportionately lowers RL
Not necessarily it lowers because RL isn't inherently changed by tubes
in parallel. To the limit, overall RL can increase if supply voltage is
increased and current stay the same or even decreases.
> proportionately increases the amount of C-Tune
Again this is true if RL effectively decreases but in the other cases
only the output tubes capacitance is what adds.
This capacitance increase without a compensating RL decrease can
sometimes be a problem on high bands where a large residual capacitance
(tubes + plateC + stray) can force to abnormally high loaded Q PI
> needed to achieve the
> desired Q of 10 to 15. Thus, using 1, 813 or 6, 813s is essentially
> same game. More tubes simply means Lower RL, More C-tune/C-load,
> tank L, and More RF circulating current (approx. = Q x I-anode.).
> matter is yet another one of amateur-radio's, brain slipped out of
> tired old wives' tales.
> cheerio, Barry.
> > >----- Original Message -----
> >From: Tom Rauch <firstname.lastname@example.org>
> >To: Randall DuCharme <email@example.com>; <firstname.lastname@example.org>;
> >Kirkwood <email@example.com>
> >Sent: Thursday, 20 September, 2001 8:29 PM
> >Subject: [AMPS] Series C at tube
> >> > knowledge of use of more than a pair of them. They have rather
> >> > output capacitance, therefore a tad of series C from plates to
> >> > tuning cap is a good idea.
> >> Why? It certainly does not lower system Q. As a matter of fact, it
> >> raises system Q.
> >> It is a popular misconception passed along among VHF operators
> >> that a small series C between the tube an tank lowers Q. It
> >> actually does the opposite.
> >> 73, Tom W8JI
> >> W8JI@contesting.com
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