There is (was) a known problem with the MMIC amplifier (comprising the IF amp into the P3) oscillating.....this instability could certainly manifest itself in what you are seeing.
The guys at Elecraft sent me a replacement rear panel interface board and my prob went away Also, make certain the coax connectors are well grounded to the rear panel with the supplied star washers. Hope this helps John On Tue May 29 5:15 , Arthur Burke sent: >Is it possible the ribbon cable is as long as it is because it will need to >eventually be routed around something else to be added later? > >Art - N4PJ > > > >On Tue, May 29, 2012 at 2:10 AM, Bob Lanning bob.lann...@verizon.net>wrote: > >> In response to my message May 23, 2012; 3:27pm on the Elecraft P3 >> reflector Roger White W5RDW in Murphy, Texas responded off-list. He had >> the same problem I described. It was not coming from the K3 but from >> inside the P3. We both noted it started after installing the SVGA. >> >> During our investigation we boy found: >> >> 1 - the signal is about 5kHz wide >> 2 - it moves either up or down in frequency ever so slowly >> 3 - moving the VFO does not change the position of the signal - internal >> to P3? >> 4 - reach back and approach the IF signal coax between the K3 & P3 >> causes it to temporarily go away >> 5 - sometimes touching the P3 cabinet caused it to disappear >> 6 - changed out the coax but it still happens >> >> When the signal crosses the VFO frequency no sound is heard - only the >> signal being listened to. But reaching back in the proximity of the >> linking coax causes it to go away. Turning PC and other gear off has no >> effect. >> >> Roger and I spent sometime isolating the source. We found a signal was >> coupling into the IF cable inside the P3 from the ribbon cable. As you >> can see from the SVGA instruction manual the ribbon cable is so long >> that if not dressed it goes across the P3 and pushes up against the IF >> coax in the unit. >> >> When the ribbon cable is dressed by folding it tightly keeping it well >> away from the IF coax the wondering signal no longer appears. >> >> If you are having this anomaly Roger and I recommend making the change >> to the ribbon cable as shown in the two pictures below. It would be >> nice to have a shorter ribbon cable. >> >> 73, >> >> Bob - W6OPO >> Roger - W5RDW >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: 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: 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
