Thanks, Ray. We think there are several issues.
At least some of these reported problems have been resolved by changes to the antenna system (connectors, baluns, and the antenna itself). If there is flashover or heat-related impedance change, the KAT500 measures a changed SWR and reacts by interrupting the key line and retuning (in mode Auto) . Some cases are related to antennas whose unmatched SWR is outside the KAT500's spec of 10:1 at 600 watts, 3:1 SWR at 1000 watts. If the antenna system (before matching) exceeds these limits, often a match can be found, but this match shouldn't be used at power above our specified threshold. More heat is dissipated by the tuner's components. If this gets way out of hand the antenna tuner does fault, which bypasses the ATU, the amplifier key line is interrupted, and the ATU red FAULT LED is illuminated. We log these faults and you can see them in your KAT500 Utility fault log display. The fault description is along the lines of "power too high for unmatched SWR'. And I believe in some cases the frequency counter is counting a signal other than the primary transmitter RF signal. I don't have much control where the pulses we count come from, but I might be able to better qualify the use of that count. If the frequency count is seen as a band change, the ATU can change antennas. We're digging into all these, and there will be firmware change to address those we can fix in firmware. I am not asserting that every one of these observations comes from antenna system problems. But some do. If your specific problem is due to a coax connector, balun, or antenna that changes impedance at high power, the changes I make in firmware aren't going to fix that problem. 73 de Dick, K6KR -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Ray Coles Sent: Tuesday, December 31, 2013 5:29 AM To: Elecraft@mailman.qth.net Subject: [Elecraft] K3/KPA500/KAT500 SWR problem As the original poster of this problem topic I have been transfixed by the subsequent correspondence on the matter. I am still assuming guilt for the original trigger, but I guess there may be a factor in the KAT 500 algorithms that may have aided and abetted my gremlin! My next move will be to revisit my rig grounding hook up (I have a pang of guilt. In that area too!). Unfortunately I am away from my shack at present on family festivity business, but I'll get right on it in a few days time, and post the result if I manage any much longed for breakthroughs! Meanwhile, thanks to everyone, and of course to the Elecraft team for picking up on this issue. HNY and 73 Ray M0XDL Sent from my iPhone Ray Coles CEng M0XDL 10 Littlemoor Road, Weymouth DT3 6AA United Kingdom ______________________________________________________________ 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
