> So the reduction in SNR (assuming equal noise power) is > 3.01 dB, not 6 dB.
That's the best case if the noise power is equal. If the "other" receiver has higher noise power (wider bandwidth, more interfering signals, etc.) the S/N reduction is greater. Even 3 dB reduction in S/N is a big hit if the DX Station you're trying to hear is at or just below the noise level. It would be a shame to turn a top performing radio into a mid-pack device by mixing the audio - because of some old wife's tail. Let those who want mixing do it externally so it doesn't impose a S/N penalty otherwise. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Kok Chen > Sent: Sunday, November 16, 2008 5:10 PM > To: Elecraft Reflector > Subject: Re: [Elecraft] K3: listening to both rcvrs > > > > On Nov 16, 2008, at 1:52 PM, Joe Subich, W4TV wrote: > > Assuming equal volume settings and equal bandwidths in the two > > receivers, the S/N will degrade by 6 dB (twice the noise voltage). > > Unless the noise is correlated, the probability density > function from > summing two random variables causes variances (noise power), not the > standard deviations (noise amplitude), to add. So the reduction in > SNR (assuming equal noise power) is 3.01 dB, not 6 dB. > > 73 > Chen, W7AY > > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
