Using just one of 20 “extra” spurs, I measuredthe spur peak at -90 with the preamp on. Base line is -125 with it on.
Turning off the preamp, the peak is -75, base line -112. The s/n remains basically with preamp on and off. The main thing is, Those spurs were not there previously. I just took the PX3 out to the shop and hooked it to another supply. The spurs are still there. Dave > On Jul 16, 2017, at 10:22 PM, Don Wilhelm <[email protected]> wrote: > > Dave, > > The KX3 is designed to be operated with the preamp on most of the time. The > only reason to turn it off is when extremely strong signals are encountered. > > The preamp eliminates many spurious signals that are actually out of band due > to its signal rejection "filtering". That has nothing to do with the > sensitivity, and it can kill extraneous results such as you are seeing. > > If it makes those responses substantial with the preamp on, then there may be > a problem to be addressed. > > 73, > Don W3FPR > > On 7/16/2017 10:07 PM, Dave Sublette wrote: >> Good point. However I am on 20 meters, which really doesn’t need the >> preamp. Besides, the spikes are 40 dB high or so. No, this behavior is >> definitely looking like a failure. I have one more thing to try. I will >> carry it out to the shop in my garage and plug it in. If it is the same >> there as in here, it’s not any external influence. Thanks for hanging in >> there with me. >> 73, >> Dave >>> On Jul 16, 2017, at 9:56 PM, Dale Boresz <[email protected]> wrote: >>> >>> Dave, make sure that the preamp is engaged on your KX3. If the preamp is >>> off and you are receiving on a quiet band, you'll see "stuff" that would >>> normally be covered by the band noise. Turn on the preamp, and the >>> artifacts that you're seeing should be pushed below the noise floor of just >>> about any band. ______________________________________________________________ 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 Message delivered to [email protected]
