[Elecraft] Anyone use a noise canceller?

[David Woolley]

David Cutter wrote:
> and spend time to set up the controls, (eg 3B7C).  It seems intuitive to me 
> that with more than one rx antenna and mixers it should be possible to null 
> more than one signal.

It's not that intuitive.  The sense antenna inputs will combine 
linearly, which means that if you just control phase and amplitude, the 
combination will be a third combination of them, not both 
simultaneously.  If you want to cancel both simultaneously, you will 
have to find two other variables, which would in practice, have to be 
the antenna locations (x and y).  As the effect would be in wavelengths, 
you would have to move at least one sense antenna with frequency.

You need two independent parameters for each simultaneously cancelled 
source.

Getting the sense antennas close to the two sources will help, as once 
you attenuate the sense signal to match the main signal, it will 
re-introduce relatively little of the other interfering signal which 
will not originate close to that sense antenna.

-- 
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.