On Wed, 11 Jun 2008 13:34:21 -0400, Joe Subich, W4TV wrote: >BTW, to answer Ed's question ... even a limited dynamic range >is generally satisfactory for "narrow bandwidth" operation.
You're exactly right, Joe, and this is quite important. Signal to noise measurements are broadband, but RTTY and PSK decoders are looking VERY narrowband. The noise in the narrow bandwidth of good PSK and RTTY decoders is a tiny fraction of the measured broadband noise, but the signal level can be the full output of the RX. It's the same sort of advantage that an RX with good IF filtering enjoys. While I haven't done studies on the subject, I'd bet that amplitude distortion and phase distortion are of much greater signifcance. And phase distortion mostly occurs in the IF of the radios as a byproduct of the filters, so I would expect radios with better filters to be better RTTY and PSK performers. These factors certainly ARE a major contributor to speech intelligibility, which is why the K2 is not wonderful in narrow SSB modes -- the amplitude and phase response of the stagger-tuned filters looks like the cut-through of a mountain range! Ed -- do you have any anecodotal or other experience on that? 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
