At 09:05 AM 6/11/2004, R. Kline wrote:
I agree in principle. However the 30-40 dB attenuation expected appears
somehwhat exaggerated from my personal experience and from what I've read.
Perhaps there is a more involved system of stubs that will do this (other
than a simple short circuited quarter wave stub in parallel with the
line)?????
73
Riki K7NJ - 4X4NJ
30 + dB is easily obtainable at the deepest part of the null with a single
filter. But the Q is fairly high.
40 + dB is easily obtainable with the typical dual-stub filter. With proper
stagger tuning it is possible to maintain 40 dB over a broader range.
I always use twin stubs--1/4 wave apart on the harmonic to get a solid
30 + dB over most of the band/mode.
I can't provide specific patterns--my notes are all at the Colorado QTH.
--John
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