[CQ-Contest] Band reject filters

Tom Delker k1ky at bellsouth.net
Mon Mar 20 21:33:53 EST 2000

You can expect anywhere from 20-25 db notch at the resonant frequency
and surrounding for a particular stub length.  You can also put two of
them in parallel for more isolation. I have done this, and it works
well... BUT nowhere near as convenient as a bandpass box like the ICE
Model 419, which includes the band-select switch.  Well worth the $200~
.  By the time you make all the stubs and come up with the switching,
you might as well have purchased a commercial box.

One advantage of the coax stubs is that you can hang them on the output
of your amplifier, where the commercial boxes go between the exciter and
the amplifier. I have some very close-spaced antennas and get very good
isolation with the ICE unit.

$.02 please.

Thomas M. Delker - K1KY CFO#395 - Smyrna / Gallatin / Short Mtn. TN
A.R.R.L. District Emergency Coordinator - Tennessee District #4
C.A.T.S. (W4CAT) - 147.30/145.23/145.49/145.17/223.98/444.45/444.65
Stones River A.R.C. (K4FUN) - http://www.members.home.com/srarc
Tennessee Contest Group (K4TCG) - http://www.k4ro.net/tcg.html
         CODE WARRIOR ©  #2  - Mobile CW Operator
     "Putting code on the road using the primary mode"

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