But remember, there are two basic loading conditions that will give a SWR of 1.2:1 ...
60R+J0 will give 1.2:1 and pull a current lower than a perfect match ... 42R+J0 will give 1.2:1 and pull a current greater than a perfect match ... (and of course all the reactive permutations around the load circle) ... On Tue, 13 Oct 2020 at 01:56, Bill Coleman <aa...@arrl.net> wrote: > 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 <donw...@embarqmail.com> 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 <donw...@embarqmail.com> > 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: aa...@arrl.net > >> Web: http://boringhamradiopart.blogspot.com > >> Quote: "Not within a thousand years will man ever fly!" > >> -- Wilbur Wright, 1901 > >> > > > > Bill Coleman, AA4LR, PP-ASEL Mail: aa...@arrl.net > 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: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 ro...@redpoint.org.uk ______________________________________________________________ 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
