On Tue, 18 Nov 2008 08:03:53 +0000, David Woolley (E.L) wrote: >In this case, there is no splitting loss, and the noise is uncorrelated >because it is being received at different locations.
It's a risky to assume that ALL RX noise is uncorrelated after being detected. While there may be differences in RF level due to antenna displacement and transmission line length, the detected audio may be correlated if some specific noise source is heard by both receivers. In other words, noise can be random or correlated. Examples: an impulse noise generated from a power line or hash generated by a swithing power supply. While both are broadband sources, they are NOT random. If both antennas hear a source like them, the detected audio will be correlated between the two receivers! So in that case, there's no advantage from combining the two RX outputs. The 3 dB advantage arises when the noise is truly random, like the noise preamps that are not common to the two receivers. 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
