In all fairness, I have to append this. I held off saying what I wanted to because I knew of someone who would be watching this reflector, and I didn't want my comments out to 'the group'.
I said "I believe it is due to resonance" and it is as far as the antenna is concerned. I also believe it is due to the K3. I bought it for my last sun cycle, and it has been a pure enjoyment for me. I'm not a 'nectar' drinker, if you get the connection. It just wouldn't be right to not acknowledge the excellent receiver. The NR is effective for man-made noise. I would like to see it better on atmospheric noise, but I don't know if that will be possible. I bought the K3 for it's operating conveniences, and it's reputation as a good receiver which I have found to be accurate. I am especially pleased with the filtering. Since I got the P3 and can see the signals beside my passband that I am not hearing, I have been amazed. In summary, even a good radio needs a resonant antenna. Rich, n0ce ----- Original Message ----- From: "Richard Fjeld" <rpfj...@embarqmail.com> To: <k...@charter.net> Cc: "elecraft posting" <elecraft@mailman.qth.net> Sent: Tuesday, November 13, 2012 11:39 AM Subject: Re: [Elecraft] K3 sensitivity below 40 meters >I think it may be due to my final comment, but first, some info. > > My pre-amp is off and the ATT is on 90% of the time. I seldom turn on the > pre-amp. With the pre-amp off, and the ATT on, I consistently hear guys > breaking in that the others in the group do not hear, and they run good > equipment. They comment on it, and believe it is due to my antenna. The > apex of my antenna is only 40 feet high. One of them has a 100 foot tower. > I believe it is due to resonance. Read on. > > I would suspect antenna not resonant, or working with a swr that is not > optimum for the frequency. (You need both.) Emphasis is given to swr > for > transmit out of concern for the finals, but I discovered years ago how > important a 1.0:1 swr is for receive. Anything less is a compromise in > receive performance. > > You say "to 'hear' an S9 signal". That has me curious. S9 is RF, hearing > is AF. Still pondering.... > > The K3 is calibrated for S9 at -50 uV with the pre-amp on. This may be the > answer to your question. It could also be that you need to calibrate your > S-meter. The XG-2 works well for that. > > Good luck, > Rich, n0ce > > > ----- Original Message ----- > From: <k...@charter.net> > To: <elecraft@mailman.qth.net> > Sent: Tuesday, November 13, 2012 8:39 AM > Subject: [Elecraft] K3 sensitivity below 40 meters > > >> >> Conventional wisdom historically has been that a receiver preamp is not >> used at 40 meters and below primarily because it is not needed, indeed >> it would typically degrade receiver performance. So why is it necessary >> to engage the 20 dB preamp on the K3 to get it to hear an S9 signal at >> the appropriate level of other receivers? >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
