KPA100/KAT100 SWR Fault
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Dear Reflector,
Hello again. I wish I wrote more often to say how good my K2 and KPA100 with KAT100 are working, but I don't. They have been working great. I built a KPA100 and KAT100 into an EC2 enclosure. Everything has worked well for quite some time now (~1 yr.). Today, I write with a problem: I fired up my rig and find that the SWR indication on the KAT100 is faulty. Here are the symptoms, transmitting into a dummy load: First, something that works properly: when I dial up the output power without transmitting, the PWR range LED switches from low to high at ~9 watts. Then -- with the ATU in CAL mode -- when I hit TUNE with the power set to the low end of either the low- or high-power ranges none of the SWR LEDs light. With the K2 still in TUNE mode, as I slowly dial up the power, suddenly all of the SWR LEDs light. This happens if I start at 1 watt and tune to about 5 watts; and if I start at 10 watts and dial up to about 50 watts. When I hit TUNE at about 1 watt and dial up the power past 9 watts, the SWR LEDS come on at about 5 watts, then I hear a relay click in the KAT100/KPA100 indicating it changed power range at about 9 watts, but the PWR range LED does not flip from low to high and all the SWR LEDs remain lit. I also get erratic HiRFL messages on the K2 display, but not reliably when all the SWR lights come on as I described above. The K2/KPA100/KAT100 currents are normal. Otherwise, the rig seems to perform as it did before this fault appeared. Output power is good, and it all seems to transmit into an antenna that I know is resonant and good on 20 m. What should I check out first? It might help to know that between the time I noticed this problem and the last time I used the rig, there was a thunderstorm in my area. While I normally set my antenna switch to ground the antenna and project my xmitters, I did not do so this time. My coax is grounded with two levels of lightening protection at the house: "cheap" lightening-arrester connectors outdoors followed by an alpha-delta coax switch with the "arc-plug" indoors. The arc-plug is not "popped", or however you describe it -- it works fine still. Perhaps a lightening pulse of some sort caught something in the SWR section of the KAT100??? Thanks to the community for help with this problem. Doug ____________________________________________________________ TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5 Capture screenshots, upload images, edit and send them to your friends through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST! ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Doug,
I suspect that one or both of the wattmeter diodes in the KAT100 are fried. It would be a good idea to check those in the KPA100 as well. KAT100 D1 and D2 and KPA100 D16 and D17. 73, Don W3FPR Douglas Furton wrote: > Dear Reflector, > > Hello again. I wish I wrote more often to say how good my K2 and KPA100 with KAT100 are working, but I don't. They have been working great. > > I built a KPA100 and KAT100 into an EC2 enclosure. Everything has worked well for quite some time now (~1 yr.). > > Today, I write with a problem: I fired up my rig and find that the SWR indication on the KAT100 is faulty. Here are the symptoms, transmitting into a dummy load: > > First, something that works properly: when I dial up the output power without transmitting, the PWR range LED switches from low to high at ~9 watts. > > Then -- with the ATU in CAL mode -- when I hit TUNE with the power set to the low end of either the low- or high-power ranges none of the SWR LEDs light. With the K2 still in TUNE mode, as I slowly dial up the power, suddenly all of the SWR LEDs light. This happens if I start at 1 watt and tune to about 5 watts; and if I start at 10 watts and dial up to about 50 watts. > > When I hit TUNE at about 1 watt and dial up the power past 9 watts, the SWR LEDS come on at about 5 watts, then I hear a relay click in the KAT100/KPA100 indicating it changed power range at about 9 watts, but the PWR range LED does not flip from low to high and all the SWR LEDs remain lit. > > I also get erratic HiRFL messages on the K2 display, but not reliably when all the SWR lights come on as I described above. > > The K2/KPA100/KAT100 currents are normal. > > Otherwise, the rig seems to perform as it did before this fault appeared. Output power is good, and it all seems to transmit into an antenna that I know is resonant and good on 20 m. > > What should I check out first? > > It might help to know that between the time I noticed this problem and the last time I used the rig, there was a thunderstorm in my area. While I normally set my antenna switch to ground the antenna and project my xmitters, I did not do so this time. My coax is grounded with two levels of lightening protection at the house: "cheap" lightening-arrester connectors outdoors followed by an alpha-delta coax switch with the "arc-plug" indoors. The arc-plug is not "popped", or however you describe it -- it works fine still. > > Perhaps a lightening pulse of some sort caught something in the SWR section of the KAT100??? > > Thanks to the community for help with this problem. > > Doug > > ____________________________________________________________ > TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5 > Capture screenshots, upload images, edit and send them to your friends > through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST! > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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