You are right Vic - it's an old discussion. I was only quoting what the engineers of ancient times thought was correct.
For myself, I have done tests adding QRN (white noise) to a weak signal using a noise generator and calibrated attenuator. Bring it up to where I can almost but not quite copy, then decrease the noise until I can. In my case it's always been more than 3dB. Of course listening to a typical HF band is an entirely different environment than listening to audio in a lab environment. Maybe I'm just a lousy weak signal guy, but that has given me a good benchmark for what I need in the way of an improvement. And maybe it's the variations among operators that make the discussion unending. My tests suggested to me that what the radio engineers of the past used was pretty close to what I'd want. 73 Ron AC7AC -----Original Message----- This argument will never die. But remember the last time you called CQ and a station came back that you could hear, but not copy. (I'm thinking CW, but it also applies to SSB). You know he is in there, but despite struggling with the narrowest possible bandwidth and every trick your receiver is capable of, you just can't get his call as he floats in and out of the noise. I maintain that even ONE dB matters in this situation. On 9/27/2013 10:03 AM, Ron D'Eau Claire wrote: > Quite true on HF. > > 3dB often matters doing weak signal work on 6 meters and up, and > sometimes on 10 meters, but on HF there are too many other variables, QSB, etc. > > Back in the 30's and 40's the "Radio Engineering" texts used to list 6 > dB as the minimum change one might expect to detect by ear on HF due > to all the propagation variations. (Back then, 10 meters was a UHF > band.) > > I always thought that was why Collins settled on 6dB for one S-unit on > their receiver S-meters. > > 73, Ron AC7AC > > -----Original Message----- > > I think there is a lot of evidence that 3dB does not matter. 10dB matters. > 6dB might matter. > > wunder > Walter Underwood > K6WRU > CM87wj > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html > -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
