carl seyersdahl wrote:
I don't want to reveal my age, but many, many years ago, (late
40's -mid50's maybe) there was a "multiband" tuning unit available, which ,
as I recall was certainly not good for 2 kw. but was useful on all bands ,
even to 10 mtrs. as I recall, but ,This is only a vague memory now.!!
I believe it was a "johnson" or maybe "B&W. can any of the "other"
oldtimers recall this unit????
I sure would like to "remember" some of these things.!!!!
National made the MB-40-L and MB-150-L multiband tanks. They covered 80-10 m
with two parallel-resonant circuits. Each one covered a 2-1 frequency range.
The circuit was arranged so that the high band circuit had little effect on the
low band circuit and vice versa. The circuits were also 'staggered' in such a
way that when one circuit was resonant at a particular frequency, the other was
not resonant at a harmonic of it.
The MB-40-L was rated at 40 watts input and the MB-150-L at 150. The little one
was often used in a grid circuit. One problem with these was that since the
tuned circuits covered a 2:1 ratio by varying the capacitance only, the Q was
high on 80 and 20 meters, and low on 40 and 10.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|