[amsat-bb] Re: Crossed or not crossed is the question

Scott Wilson s.wilson at yahoo.com
Mon Sep 17 12:20:34 PDT 2007

> My question to you guy is, that after i bought this one, I thought 
> that it would be hard to operate in full duplex mode as i almost 
> get cross talk on the 70cm side. 

Polarization is not the only thing to consider. There's also wattage, 
feedline arrangement, and receiver quality. 

I'm using a Cushcraft which has the 70cm alongside the 2m elements. For
FM, I'm running 75 watts xmit on 2m. With the default feedline which
consisted of two 3foot segments teed to a length of RG-58, I was getting a
lot of desense on transmit. I changed to seperated feeds of higher quality
coax, and now am running full duplex just fine.

I haven't been able to run full duplex on AO-7 yet though. That setup
consists of the same antenna plus an FT-817 for rx and transmitting SSB at
5-35 watts from an IC7000. I get crosstalk in the FT-817 even at 5 watts
xmit from the IC-7000.


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