[CQ-Contest] Stubs are not a joke

David Robbins k1ttt at berkshire.net
Thu Jul 3 01:27:40 EDT 1997

Scott Robbins wrote:
> I have been doing some work on a SO2R contest station and have only
> recently come to the question of using band stubs for nulling out
> unwanted signals.  I have noted that at 500 watts I don't really have
> a problem, but at 1500 watts it starts to present a little bit of a
> dilemma on a few band (but not all) combinations.
> I understand the generalities of using stubs, but this is one question
> I don't know the answer to:  is right at the output of the amplifier
> the only spot the stub is useful/usable?  I use a couple of mono-
> banders on a remote coax switch that could easily have stubs on T
> connectors added at the switch.  I have seen nothing to indicate this
> is indeed possible, but wanted to inquire with the thought pool
> here first.
> --Scott, W4PA

sure, the stubs can be anywhere along the feed line.  they are most
commonly at the amp output in m/m stations because that is an easy
place to put them when the amp will only be on one band.

check out:
for some notes on stubs, including the advantages of pairs of

David Robbins K1TTT (ex KY1H)
k1ttt at berkshire.net   or   robbins at berkshire.net

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