Do you have Mic+Line enabled in the K3?
Sounds like RF on the cable between the K3 Line-Out and computer Line-In is being sent back to the K3 Line In jack. Improve the grounding of your station, including direct grounds on both the K3 and computer to the common ground point and add common mode chokes to both your feedline and the "Line In" connection to your computer. 73, ... Joe, W4TV > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Bud > Governale, W3LL > Sent: Tuesday, January 19, 2010 1:34 PM > To: [email protected] > Subject: [Elecraft] K3 Audio/RFI Feedback > > > I'm experiencing audio/RFI feedback on 80M between the > frequencies of 3650 KHz to 3850 KHz using a full-size 80M > vertical 100' from the radio. > SWR is under 2:1. No difference if I use the built-in ATU. > > If I key the K3 and tap the mic once it goes into > motorboating with full output (100W). > > The K3 monitor is set at 0. > > If I mute the PC line-in sound card there is no motorboating > feedback. If I reduce the K3 mic setting from 30 toward 0 > there is no motorboating feedback. If I reduce the PC line-in > volume setting toward 0 there is no motorboating feedback. If > I pull out the cable to the PC line-In there is no > motorboating feedback. If I pull out the cable to the PC > line-Out there is no motorboating feedback. At 50W setting > the motorboating starts but is not self sustaining. At 90W > setting the motorboating is self sustaining. > > Any suggestions on where next to look - or a solution? > > 73, > > Bud W3LL > [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 ______________________________________________________________ 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
