[CQ-Contest] SO2R Questions

[Pete Smith]

At 09:58 AM 5/29/03 -0300, Scott Nichols wrote:
>I'm in the process of converting my station to SO2R and need some help...
>
>I have 2 MP's, one amp (for now), and one set of antennas (for now) 
>consisting of a tri-bander and several dipoles, all fed through one coax 
>switch in the shack...
>
>My biggest concern for the moment is antenna selection/switching and 
>filtering, so as not to blow up one of the MP's front-ends...Been reading 
>everything I can find on this, but unfortunately, I'm don't know enough 
>about it to fully understand everything...

Just a couple of thoughts to add to the excellent info from others.  The 
MPs have an RX antenna loop out the back that can be used for inserting 
some sort of receiver protector, which might be a good idea.  If you look 
back in the towertalk archive, you'll find a fairly extensive thread on 
this in November 2001.

As one smart person observed during that discussion, a first step is to 
learn just how much RF actually gets from one antenna to another (or from 
one radio to another, not always the same thing).  WE9V did these 
measurements in his station, and wrote about it in an excellent article in 
the May/June 2001 National Contest Journal, titled "Antenna Isolation in 
the Real World."

For what it's worth, I opted for a minimal SO2R combination.  With my 
second radio on a trap vertical some 300 feet from my tower, I have had 
relatively few problems (and no destructive ones) operating SO2R with no 
filtering or other protection.  It helps to keep the second radio on a band 
lower than that used by the run radio, and stubs or bandpass filters would 
certainly be helpful.

73, Pete N4ZR
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