"No Spam" wrote in message
. ..
I'm trying to come up with some ideas for multi-op field day station
isolation. Main problem will be front end desens between Voice and CW
portion of the same band. Main concern is on 20M

I'm thinking simple stub filters. Though they are wide, I would think
that there would be a few DB of isolation 100Khz away. Perhaps several in
parallel to narrow it up a bit.

Would a simple LC resonant circuit with perhaps 20-30Khz of BW work?

Any thing else I should be considering?


Thanks You!

coax stubs are too broad... use lumped filters if you need them, but its
hard to get real good isolation within a band. one proven way to help
prevent problems is proper prior planning of the layout, put the cw and ssb
stations as far apart as possible. if both are using dipoles or yagis
arrange them so they are in each others nulls when pointing in the prefered
direction. using one with horizontal antenna and the other vertical may
also help.

On Wed, 07 May 2008 21:35:21 +0000, Dave wrote:

"No Spam" wrote in message
. ..
I'm trying to come up with some ideas for multi-op field day station
isolation. Main problem will be front end desens between Voice and CW
portion of the same band. Main concern is on 20M

I'm thinking simple stub filters. Though they are wide, I would think
that there would be a few DB of isolation 100Khz away. Perhaps several
in parallel to narrow it up a bit.

Would a simple LC resonant circuit with perhaps 20-30Khz of BW work?

Any thing else I should be considering?


Thanks You!

coax stubs are too broad...

I thought so too, until I tried one. I was working 20 meters on a
tribander ans a KW, teh guy beside me was on a 40/30 meter fan dipole
running legal limit. Antennas were less than 50 feet apart. Without th
stub, I couldn't work period, with it, it knocked the 40 meter signal
completely out, FAPP.

-73 de Mike N3LI -