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

[Vic K2VCO]

Tayloe Dan-P26412 wrote:

> However, if the situation is a weak signal situation where 
> the receiver noise floor is at least partially masking 
> the desired signal, we have a different situation.  Band 
> noise and stations on the band will both be correlated coming 
> out of both receivers and thus get a 6 dB improvement.  On 
> the other hand, the internal noise produced in each receiver 
> is independent and thus uncorrelated.  While correlated 
> signals add voltage wise (V + V = 2V or 6 dB gain), 
> 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!
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco