[Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:
> If anyone has done a K3 to IC-7800 comparison,

Here's another VERY interesting set of RX measurements. The Noise Power 
Ratio (NPR), is essentially a measure of how broadband noise and QRM 
outside the passband show up inside the passband. It combines the 
effects of phase noise and various forms of non-linearity in the RX 
system. First study the methodology, then the data. Big numbers are 
better. :)

http://www.ab4oj.com/test/docs/npr_test.pdf

The guy who did this work is Adam Farson, VA7OJ, AB4OJ, an EE retired 
from a career in telecom, now living in Vancouver, BC. He spoke to our 
local ham club last weekend, and his presentation was quite interesting. 
Several of us had dinner with him. He seems quite genuine, no horses in 
the race, his objectives seem to be the same as Rob Sherwood and my own 
-- to put mfrs feet to the fire to improve the receive performance and 
signal quality of the stuff they sell us. :)

There's an important caveat to his work. The NPR measurements require 
very sophisticated band-stop filters in his instrumentation setup, and 
based on the filters he has been able to source, that limits the 
frequency range where he can do his measurements. An example is in the 
footnote for the Flex-6700, which has no preselector for the range where 
he had to do his measurements, which may have caused that radio to 
measure worse than it would on the ham bands.

73, Jim K9YC