This reply is going back in the thread, on purpose because I've settled the matter. The follow on discussion in the other thread was informative (thanks) and I'll store it in a note for the station.
TL;DR; Situation is resolved. Bad RF due to crap elbow connector and lack of diligence in ferrite application on AUX serial cabling. -- Gory Details: Some background that I apologize for not mentioning (and wasting your time - very sorry). But, I didn't know at the time of the original question post. When I was testing *after* the post, I went to the KPA and flipped the display to show TEMP. So when I repeated the experiment (even into a dummy load), I heard the clicks as before, but when I glanced at the LCD panel of the KPA I noticed that the Frequency was bouncing around. (14 Mhz then 18Mhz then back to 14Mhz and then show the TEMP again). I thought, "why on earth is the KPA trying to use a different frequency??" That triggered some evaluation of an earlier email (name withheld) that mentioned RF in the shack. I dug through the parts bin and got a handful of snap-on ferrite and loaded up the AUX Cables on the ends.. Tons of ferrite. OK so then I re-ran the test. Same result but slightly better. Not as much relay chatter. Then I began to wonder about the RF again. I decided to move some equipment. I moved the KPA from the top of the KAT and placed it nearby but not as it was before. Re-routed the coax and so on and re-tested. But this time not as pervasive. Some relay chatter, but less clicking (and less band-switching in the KPA). OK, so we're getting somewhere... Then I took a real good look at the coax. Sure enough those Amphenol elbow connectors were not what I thought they were. Upon closer inspection I realized they were (let us just say) not what I wanted. I swapped them out and lo and behold the problem was gone. No amount of CW into the Dummy Load would trigger the click (ie., the "band switch" clicking). It was the band-switch relay that was clicking after all. Not the Bypass to MAN and vice versa... I was too proud to notice that I had a couple of connectors that were not the prime quality. And too proud to realize I hadn't really applied as much ferrite where it needed to be. I am really sorry to spin up so many great minds to think about this. Lesson learned. Really make sure RF(I) is eliminated. Really. Eliminated. Now, to whom should I send a complementary coffee gift card with the essential fix... Thanks very much. I return you now to the list for more important issues. Thanks. --- 73, Jeff W7BRS https://blog.w7brs.com On Monday, January 1st, 2024 at 1:31 PM, Jeff Wandling <j...@w7brs.com> wrote: > W7BRS> comments in-line below. > > > > > --- > 73, Jeff W7BRS > https://blog.w7brs.com > > > > On Monday, January 1st, 2024 at 1:21 PM, Andy Durbin a.dur...@msn.com wrote: > > > > > "Actual Results: The ATU-500 clicks between Bypass and MAN (by "clicks", I > > mean only what I can infer from the behavior -- it is as if the ATU-500 is > > either using the memory-based ATU settings of the previously tuned settings > > and switching between that and what seems like a Bypass mode) -- the > > clicking is rapid and persistent at the onset of the CW message." > > > > How does your KAT500 know what frequency to use? Does it have a serial data > > interface or does it depend only on the internal RF counter? > > > W7BRS> AUX cable between K3 to KAT-500 and KAT-500 to KPA-500. They are in > serial communication per Elecraft protcol(s), whatever those are. > > > What KAT500 mode (AUTO, MAN, BYP) is selected when you observe this anomaly? > > > W7BRS> Per manual for KAT-500/KPA-500 the stated "nominal" mode is MAN. So I > leave the KAT-500 in MAN after tuning the antenna to 1.1. > > > I ask these questions because I doubt the problem has anything to do with > > SWR thresholds. > > > W7BRS> Interesting. I am only guessing that the excessive clicking in the > KAT-500 was the KAT-500 going in/out of BYPASS. (This isn't the clicking > associated with the Tune-search for L/C. It's a different kind of click. I > don't know how else to describe it other than a single kind of click as if it > was a single relay in operation in the KAT-500 -- that same kind of 'click' > sound that would occur if you switched between MAN and BYPASS on the KAT-500. > Same sound. But that's not definitive enough I suppose. I don't have any > Serial Log data from the Utility to base that guess. > > > W7BRS> Thanks for the questions. I've got a few other replies to sort through > with other suggestions: > > > 1. Try dummy load vs. real antenna > 2. Carefully listen if clicks are syncopated with CW (they aren't but I can > listen again to make sure). > 3. RF/RFI - Not likely except that Serial AUX cable might be picking up some > RF.. I could attach some ferrite cores around it to rule out. Otherwise the > shack is weighted down with ferrite in all the right places -- Everywhere. > /hi/ > > W7BRS> Thanks again for the questions, very good. > > > Andy, k3wyc > > > > ______________________________________________________________ > > 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 j...@w7brs.com ______________________________________________________________ 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
