[Elecraft] Re: K3: listening to both rcvrs - Reduced receivernoise floor

[Paul Christensen]

>> uncorrelated noise adds as the square root of the sum of the squares 
>> sqrt(V*V + V*V) = 1.4V or 3 dB gain.
>
> This implies that if I am listening to a very weak signal close to the rx 
> noise floor (at least at my urban QTH this is rare and would only happen 
> on the higher bands), it would pay to activate the sub-receiver in 
> diversity mode even with the same antenna!

But wouldn't the benefit be purely the result of the psychoacoustical phase 
difference between the two audio sources rather than amplitude when 
activating the 2nd Rx?

With two correlated signals, it would seem that both noise *and* the desired 
signal increase by the same amount (i.e., 6 dB).  Likewise, with two 
uncorrelated signals, both the noise and desired signal also increase by the 
same amount (i.e., 3 dB)  So, from a SNR standpoint, what is the benefit?  I 
can see where there may be a psychoacoustical phase benefit, but not of 
amplitude.

Paul, W9AC