This comes up quite often, and here is a reply from Wayne about it. You can check your PX3 as follows.
> Are you using a PX3 or P3? Assuming it's a PX3, try this: > > - make sure RX I/Q is set to ON (KX3 menu) > - make sure the PX3->KX3 cables are fully seated > - connect an antenna to the KX3 > - switch to 20 meters > - turn the preamp ON and set the PREAMP menu entry on the KX3 to 20 dB > - set the PX3's SPAN to 50 kHz or lower > - adjust the REF level so the "grass" (noise floor) is close to the bottom of > the spectralplot > > With the above setup, there will typically be no visible fixed spectral lines > on the PX3. > > As described in the PX3 FAQ on our web site, very wide SPAN settings and low > front-end gain (e.g., turning off the preamp) will reduce the signal-to-noise > ratio of an RX I/Q-based pandapter, including making wideband spurs more > apparent. The same limitations apply when using the KX3 (or other quadrature > downconversion radio) with a PC sound card. Typically this doesn't impact > usability, e.g. locating signals of interest. In fact most sound cards are > limited to displaying about 48 kHz of spectrum, while the PX3 can go wider > thanks to its high-performance/high-speed A-to-D converter. 73 from David GM4JJJ > On 16 Jul 2017, at 23:47, Dave Sublette <k...@arrl.net> wrote: > > Tnx Roger and Matt. Roger — I don’t have the KX3/PX3 interfaced with the > audio on the computer. I do have the usb port connected. > > Matt — I believe it is the 2.5 mm jacks that carry the Rx I/Q between the KX3 > and PX3. I unplugged the antenna and the spikes are still there. I > unplugged the Rx I/Q plug from the PX3 and the irregularly space spikes went > away and the regularly spaced spikes were still there at the same levels as > when the cable was plugged in. > > I’m still thinking there is a failure in the PX3. > > Dave >> On Jul 16, 2017, at 6:06 PM, Dave Sublette <k...@arrl.net> wrote: >> >> I have had my PX3 for a little over a year (I think). It has been used >> sparingly. Until this afternoon, it has worked perfectly. Now I see a >> spike in the center of the display and periodic spikes across the entire >> screen. Almost all are symmetrical in frequency and amplitude about the >> center line. There are some that are not symmetrical. I have plugged and >> unplugged all the cables, taking care to see that each is fully into the >> socket. >> >> So, perhaps I have a failure that requires returning to Elecraft? Have any >> of you had the same experience? >> >> 73, >> >> Dave, K4TO >> ______________________________________________________________ >> 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 >> Message delivered to k...@arrl.net > > ______________________________________________________________ > 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 > Message delivered to gm4...@yahoo.co.uk ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
