Topband: Re: topband RX

[Larry Molitor]

A question for those more versed in communication theory than myself:

Through the years I have tried, in vain, to correlate receiver test bench 
data with on-the-air performance. I guess that personal preferences create 
a good deal of subjectivity in such comparisons, but still.....

On topband, at this QTH, I observe virtually no difference in performance 
between any of the receivers I've had in the last 30 years. Some of this 
might be due to little problem with very large in-band signals and part due 
to using minimum system gain to do the job. What's left is a noise floor 
that's so high it would make most topband enthusiasts break down and cry.

It's my opinion (and others) that this high background noise is an 
incoherent mess of literally millions of spurious signals from switching 
power supplies, wireless phone IMD's, BC harmonics, power line leaks, and 
who knows what else generated in an urban environment.

It would appear that the high noise floor tends to mask performance 
degradations caused by high phase noise and some of the IMD problems 
inherent in modern synthesized radios. Is this a valid guess or is there 
more here than meets my eye (and ears)?

Thanks & 73,

Larry - W7IUV



--
FAQ on WWW:               http://www.contesting.com/FAQ/topband
Submissions:              topband@contesting.com
Administrative requests:  topband-REQUEST@contesting.com
Problems:                 owner-topband@contesting.com