Topband: Omni VII performance on 160m

[Richard (Rick) Karlquist]

The concept of IP3 is that you can describe nonlinearity
in a single number.  This presupposes that IP3 is independent
of excitation level below some threshold, which is typically
something like 10 dB below 1 dB compression.  I have measured
a number of devices that simply don't have a defined IP3
value, since I measure a different IP3 for every excitation level.

I am wondering if anyone has run into this on ham radio receiver
measurements?

Rick N6RK