Hey everyone, I was having RX problems on my 70cm radio during the
contest this weekend and I'm hoping to get some suggestions of things to
try before I start talking to Icom.
The setup: I use an IC-7000 for 6, 2, and 70. On that radio, 2 and 70
come out the same coax port. I have a piece of coax running out to a
diplexer, and then individual coaxes running to the two antennas. I am
a rover, so all my antennas are piled up on top of each other in close
proximity. My 6 and 2 antennas are on a different mast, so they can
occassionally be pointed into the front or rear of the 70cm antenna.
The symptoms: Most of the time, stations would tell me they could hear
me just fine, but I could not hear them at all. These would be big
fixed stations from good sites where I had no trouble contacting them on
any other band (including 2m, same radio). On some of these contacts I
had to resort to CW to complete the contact, whereas sideband was fine
even on microwaves to the same station. I had trouble hearing them on
CW too.
However, sometimes it just worked and from much more marginal sites,
like aiming just past the corner of a building and through trees. And
then this would be working the same station I had trouble hearing
earlier, but from a different site.
I did not pay close enough attention to the noise levels at each site
and on each band, but my sense is that 2m noise was very very low (which
might be a different problem?) and 70cm noise was much higher.
So, any ideas if there's anything I could try? I have limited test gear
here. I made the coax, but if that were a problem I'd expect people
couldn't hear me. I think that rules out the diplexer being a problem
too.
--
Chris Lumens - KG6CIH
Hike * MTB * XC Ski * Haskell
Research - Experimentation - Testing - More Testing
_______________________________________________
VHFcontesting mailing list
VHFcontesting@contesting.com
http://lists.contesting.com/mailman/listinfo/vhfcontesting
|