[TowerTalk] station to station interference

Jim Brown jim at audiosystemsgroup.com
Tue Sep 27 20:36:00 EDT 2016


On Tue,9/27/2016 5:17 PM, Steve NR4M wrote:
> Any guidance on what I should be looking for would be of great help.

Hi Steve,

What radios and amps?  Some are a lot cleaner than others. The 
interference you describe sounds like it could be phase noise. The 
TXNoise collection of ARRL Lab test data (on my website) is a good place 
to see differences between rigs on TX. That data is several years old. 
Since then, new firmware has improved the FTDX5000 and others in that 
line, the new synth board designed for the K3S is about 10 dB better on 
phase noise on both TX and RX. The Flex rigs didn't test well, but Flex 
issued new firmware that, I'm told, improved it significantly. But I 
can't get one to measure. I DID measure an FTDX5000 and confirmed the 
improvement. Data is on my website.

Could one of more of the amps be overdriven, or otherwise behaving 
badly? Good chokes on all antennas at their feedpoints?

73, Jim K9YC



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