[amsat-bb] Re: AMSAT-BB Digest, Vol 2, Issue 504

OZ1MY oz1my at privat.dk
Tue Aug 14 03:18:47 PDT 2007

Hi Richard,
A quarter wave stub tuned to 2 meters will be 3/4 wave at
70 cm.
Therefor it will reject 70 cm as well.
Greetings from Copenhagen.
73 OZ1MY
----- Original Message ----- 
From: <richard at g3rwl.demon.co.uk>
To: <amsat-bb at amsat.org>
Sent: Tuesday, August 14, 2007 10:32 AM
Subject: [amsat-bb] Re: AMSAT-BB Digest, Vol 2, Issue 504

> Scott
> > The other downside is that even with two transceivers, I'm unable to
> > full-duplex. The two bands on the antenna use seperate elements and feed
> > points, but share a boom. Transmitting on 2m completely overloads the
> > front-end of the IC-7000. While full duplex would be useful, it's not
> > absolutely necessary.
> Theres also the old fashioned stub, you put a 2m quarter-wave open-circuit
stub on the 70cm feeder close to the input of the preamp (maybe another
close to the input of the rig). A little bit tricky to tune (fabricate it
long and snip tiny bits of it off until you get maximum attenuation).
> 73
> Richard G3RWL
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