Jim, it was a ground loop problem caused by the metal spacer. You'd have to have a very early K144XV for it to be present. Here's how to tell if yours needs modifying as described in the mod instructions:
This change was incorporated into the K144XV assembly process in September, 2010. All K144XV's shipped after September are already modified. If you are unsure, remove the K3 top cover and inspect the K144XV module mounted on the left side panel. If there is a screw in the hole directly above the Elecraft name on the top label, the modification has not been done. The K144XV module is directly under the K3 top cover mounted on the left side panel (when the front of the K3 is toward you). The label says "Elecraft K144XV 2M Module". You probably don't need to completely remove the top cover. Just lift it enough to see that label. Note that there should be two empty holes in the top - that one and one closer to the side panel (unless Elecraft has redesigned the cover to remove the superfluous holes). Note that there SHOULD be a screw in a hole just to the right of the word "STATUS" on the edge farthest from the side panel. If yours has a screw in that location (instead of an empty hole), let me know and I'll dig up a copy of the mod sheet for you. I can no longer find it on the Elecraft web site. 73 Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Miller Sent: Saturday, May 18, 2013 1:59 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K144XV Strange Readings Will someone please describe this "center spacer" so I can verify whether it is in mine or not? Was it an active part of the circuitry? If I have it in mine can I just remove it without any other modifications? Why does removing an inactive part have any effect? 73, Jim KG0KP -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Ron D'Eau Claire Sent: Friday, May 17, 2013 10:20 PM To: mtebe...@mchsi.com; elecraft@mailman.qth.net Subject: Re: [Elecraft] K144XV Strange Readings Mike: First e-mail k3supp...@elecraft.com or call them (831-763-4211) for further guidance. As Dave says the center spacer was removed very early on when some stability issues arose. I have an early pre-production board, but it was stable with and now without that spacer. This sounds like something new but may be something that you can tackle yourself. 73, Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Michael Eberle Sent: Friday, May 17, 2013 7:57 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K144XV Strange Readings Dave, Yes that is exactly what it appears to be doing. My frequency counter is showing RF at 153.600 MHz regardless of what part of the band it is tuned to. I removed the K144XV Reference Lock Board and there was no change. Is there anything that can be done to correct this, or do I need to send it back to Elecraft? I just bought it 2 months ago so it shouldn't be an early production run board. Thanks, Mike KI0HA On 5/17/2013 6:50 PM, WW2R Elecraft wrote: > Both my early edition K144XV were not unconditionally stable and were > swr intolerant > > I think you will find that the 3:1 swr is because it is oscillating > "out of band". Try listening on a scanner. I have experienced this on > my two k144xv and g4ddk had the same issue with his. One example > produced 162MHz, one 168MHz one around 158MHz. When you tune or speak > it stabilizes and generates > on 2m My k144xv were fine if I operated at the bottom end of 2m where the > swr was 1.1:1 but my antenna swr rose to 1.6:1 at around 144.8MHz and > above this point it showed the instability you mentioned > > > Mine were replaced with the later production run k144xv (the one > without the centre spacer, but that could just be coincidence!) and > the issue has not arisen since > > Dave > > G4FRE ______________________________________________________________ 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 ______________________________________________________________ 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 ______________________________________________________________ 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
