[Elecraft] XG3 device...

[Al Lorona]

Geoff, you're right. But I gather you're talking about two closely-spaced 
sources?

I think the original question was whether harmonics from a *single* source would 
be a real problem. After all, this thread was originally about the XG3.

Generally, any harmonics aren't going to be a real big problem. They'll be 
well-filtered by the time they get to the real nonlinearities in a receiver. 


And even if they're not, consider a 7 MHz signal coming out of an XG3 along with 
a 2nd harmonic at 14 MHz.

The third order mixing products will be at 0 and 21 MHz. This will only be 
dangerous if the receiver is either a zero-IF design or has very poor front end 
rejection.

The problem might get a little worse as you go down to 160 meters, but even then 
the 3rd order product will be at 5.4 MHz, which any 160m receiver worth its salt 
should be able to reject.

Al  W6LX