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Old 25-Nov-2020, 4:43 PM   #76
Senior Member
Join Date: Jan 2010
Location: Dallas, TX
Posts: 171
Originally Posted by rabbit73 View Post
It is possible to modify the graph for clarity:...
Yes, in many cases, the graphical images could be helpful.

Having the raw data to analyze, when looking for relatively small performance differences (say between two different antenna preamp combinations), could help to ascertain differences of less than one dB.


Have designed, built, and tested several low-noise preamplifiers in combination with custom high gain antennas.

It is somewhat straightforward to evaluate relative noise figure of amplifiers, or the relative gain of antennas.

But more difficult to evaluate the performance of a particular preamplifier and antenna combination. The degree of impedance match or mismatch between amplifier and antenna can affect both noise figure and effective antenna gain.

Further complication is (in KY) receiving stations at 100 miles distant, there are large variations in signal levels vs time.

It is difficult to ascertain performance differences, especially when the performance difference may be a dB or even less.

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