Topband: Rig Comparisons

Jim Brown jim at audiosystemsgroup.com
Tue Jul 29 01:00:36 EDT 2014


Online chatter about what rigs were used at WRTC and why got me to 
pursuing something that's been bugging me for a long time -- the band 
pollution produced by many of today's transmitters. K6XX tackled it in 
talk to NCCC last fall, and over the weekend, when IOTA was slow (which 
was a lot of the time in W6) moved on it.

For almost ten years, we've seen lots of analysis of receiver 
measurements, but little attention to transmitter cleanliness. So on 
Saturday, continuing on Sunday and today, I've been pulling data from 
ARRL product reviews, putting it into a Quattro Pro spreadsheet, and 
plotting a dozen or so rigs on the same graph. Two sets of data -- the 
spectra 5 kHz either side of a CW signal, and phase noise out to 1 MHz, 
pretty much tell the story.

All of the data is from ARRL -- my contribution is organizing it so that 
we can better learn from it.

k9yc.com/TXNoise.pdf

This is rough, a work in progress. Comments appreciated.

The slides for K6XX's talk are at k9yc.com/publish.htm

73, Jim K9YC


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