A properly sourced and terminated length of coax is not inductive. You have classic symptoms of common mode current problems.
J On Nov 19, 2014, at 9:31 AM, Milverton M. Swire via Elecraft <[email protected]> wrote: Jim, RFI is not the issue here.What is happening is a matter of " Inductance " By adjusting the length of the Jumper, the Impedance is adjusted accordingly. ((((73)))) Milverton. From: James kvochick <[email protected]> To: "N2TK, Tony" <[email protected]> Cc: "[email protected]" <[email protected]> Sent: Wednesday, November 19, 2014 7:19 AM Subject: Re: [Elecraft] Strange K3 & KPA500 Issues fixed with a longer coax cable? We tried all the normal "common mode" tricks, but the feedline length appeared to be the most effective. Jim K8JK Sent from my iPad > On Nov 19, 2014, at 7:32 AM, N2TK, Tony <[email protected]> wrote: > > I had a similar problem many years ago with an L-4B amp. > I wonder if adding ferrite to the coax would solve this problem? > GL > N2TK, Tony > > -----Original Message----- > From: Elecraft [mailto:[email protected]] On Behalf Of Jim > Kvochick > Sent: Tuesday, November 18, 2014 9:16 PM > To: [email protected] > Cc: [email protected] > Subject: [Elecraft] Strange K3 & KPA500 Issues fixed with a longer coax > cable? > > I've stumbled into a strange problem. > > I have 4 friends with similar K3 stations to my own; K3 >>> KPA500 >>> > KAT500. The stations are powered with similar power sources. > > One station sounds fine, works great. The other 4 had strange issues that > manifested themselves as audio distortion when running the amplifier. After > looking all over for RF and grounding issues, we swapped the coax cable from > the K3 to the amplifier, with a longer cable (about 6 to 7 feet - largely > because that was the only free cable we had handy). > > Making the cable from the K3 to the amplifier longer eliminated the issue. > putting the cable back brought the problem back. Making a new short cable > still left us with audio distortion. The only thing that seemed to solve > the issue in all 4 cases was making the K3 to amplifier cable longer. > > This got me to investigate my own station. It turns out that the cable I > used between the amplifier and the radio was about 6 feet long. Swapping > this cable for a shorter length brought about audio distortion symptoms. > > Does anyone have any thoughts about this? > > Cheers > > Jim K8JK > > ______________________________________________________________ > 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] > > ______________________________________________________________ > 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] ______________________________________________________________ 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] ______________________________________________________________ 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] ______________________________________________________________ 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]
