[Amps] output ckts.

[Vic Rosenthal]

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