SWR on the problem antenna is below 1.2:1. It’s a trap dipole - designed for that band.
It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more. > On Oct 12, 2020, at 2:12 AM, Don Wilhelm <[email protected]> wrote: > > Bill, > > I would suggest that you check the SWR on the antenna before concluding it is > an RF feedback problem. > Don't forget that the balun may be breaking down with power and show no > problem at lower power (like from an antenna analyzer). > > Don W3FPR > > On 10/11/2020 8:53 PM, Bill Coleman wrote: >> Don, >> >> I finally got around to running my K3 into a dummy load. >> >> I had no problem running 100w or even 110w with a dummy load. Current draw >> from the power supply was 22 A and 23 A, respectively, on the K3 display. No >> HI CUR indications. >> >> External wattmeter validates the output. >> >> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to >> take it down, and now I’m using a trap 80/40/20m dipole through the tuner. >> No HI CUR indication on that antenna, either. >> >> Even though I have current baluns on both antennas, I’m thinking that my HI >> CUR problem may be related to RF feedback in the shack. >> >> Do you concur? >> >> I’m in the process of a number of shack improvements, including antenna >> replacements and grounding and bonding, so that might take care of it. >> >>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[email protected]> wrote: >>> >>> Bill, >>> >>> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy >>> load). >>> If it is into an antenna, there are a whole lot of guesses about how the >>> antenna behaves with higher power levels than your antenna analyzer shows. >>> So check it with a dummy load to eliminate the possibility that the problem >>> is in the antenna. >>> >>> Put an external wattmeter in line with the dummy load to eliminate >>> questions about the calibration on the K3 wattmeter. >>> >>> If you can measure the actual current drawn, that would also be helpful. >>> >>> 73, >>> Don W3FPR >>> >>> On 1/11/2020 11:18 AM, Bill Coleman wrote: >>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime >>>> after that, I noticed that on 12m, I’m seeing a HI CUR indication when I >>>> set the power level to more than about 80-85 watts. The K3 will back off >>>> on the power level, then slowly ramp back up until it hits HI CUR again. >>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the >>>> transmit gain calibration at both 5 and 50 watts, as specified in the >>>> instructions. Just in case something went awry, I ran it again. >>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 >>>> ought to be able to produce over 110 watts on 12m. >>>> I’m not seeing this issue on other bands. >>>> No issues with calibration >> Bill Coleman, AA4LR, PP-ASEL Mail: [email protected] >> Web: http://boringhamradiopart.blogspot.com >> Quote: "Not within a thousand years will man ever fly!" >> -- Wilbur Wright, 1901 >> > Bill Coleman, AA4LR, PP-ASEL Mail: [email protected] Web: http://boringhamradiopart.blogspot.com Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ______________________________________________________________ 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 Message delivered to [email protected]
