Re: K3 APF Adjustable Q

Posted by Kok Chen on Nov 01, 2010; 10:28pm
URL: http://elecraft.85.s1.nabble.com/K3-APF-Adjustable-Q-tp5688670p5695369.html


On Nov 1, 2010, at 12:53 AM, David Woolley (E.L) wrote:

> Quote para 2, both points:  Reciprocity still applies with respect to gain and off axis effects.

My mistake.  David is correct on this point.  

Given a constant signal power across the receiving antenna terminals, the SNR would be constant no matter what the beam patten is (as long as noise is isotropic).  The integrated noise power is constant no matter what the beam shape is.

No, this does not mean you should not use a more directive antenna :-).  A more directive antenna directed towards the signal will increase the signal power while not increasing the noise power.

73
Chen, W7AY



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