Re: [Elecraft] HI CUR warning on K3
On 11/8/2023 8:21 AM, Pete Smith N4ZR wrote: I've fairly well established that the problem is not at the antenna, but arising somewhere in the grounding/RFI protection in my station, since it occurs only on one band and (more importantly) because it stopped totally after I re-tightened all the connections in my grounding system yesterday That can certainly be a major cause of problems with RF in the shack. The Carolina Windom incorporates a line isolator 22 feet down from the feedpoint, but technical questions have been raised about exactly what you describe, and I'm not technical enough either to question the analysis or to experimentally measure the common mode current on the feedline. ALL off-center-fed antennas are a train wreck for RF in the shack, and for blowing "line isolators" and chokes. This is because their strong imbalance puts huge common mode current on the feedline. They are a very bad idea, especially if running high power. Anything done to try to "fix" them is putting lipstick on a pig. 73, Jim K9YC __ 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
Re: [Elecraft] HI CUR warning on K3
Hi John - I've fairly well established that the problem is not at the antenna, but arising somewhere in the grounding/RFI protection in my station, since it occurs only on one band and (more importantly) because it stopped totally after I re-tightened all the connections in my grounding system yesterday . The Carolina Windom incorporates a line isolator 22 feet down from the feedpoint, but technical questions have been raised about exactly what you describe, and I'm not technical enough either to question the analysis or to experimentally measure the common mode current on the feedline. Further complicating the issue, the feedline to my CW is very long - on the order of 250 feet, a mix of RG8-X and Buryflex. This arose because I put the antenna switch at the base of my tower, and the feedpoint of the CW is at one extreme of what amounts to a triangle with the antenna switch and the shack. 73, Pete N4ZR On 11/7/2023 11:15 PM, j...@kk9a.com wrote: I am not very familiar with a Carolina Windom but I believe it is just a horizonal wire fed off center. These types of antennas can have significant common mode current on the feedline. Perhaps there is more current on 40m than on 80m so it works on 80m. A resonant dipole with a choke may solve this HI CUR issue. John KK9a Pete Smith N4ZR wrote: I send a few characters of CW into my Carolina Windom on 40M and after a delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR warning, and the audio gain is reduced significantly. Touch the AF gain control and it instantly returns the gain to normal, but frequently the HI CURR warning returns over and over, without any additional transmissions. This sequence does not happen, even with 1500 watts, into my dummy load, nor does it happen on the same antenna on 80M, or on 20 meters on my tribander. I've read the HI CUR warning discussion on page 65 of the manual, but it doesn't seem relevant, because I don't have external speakers. The fact that it only happens when feeding an actual antenna on one band suggests RFI, but the fact that the HI CUR warning and gain reduction recur again and again long after any RF has me puzzled. Any suggestions gratefully accepted! __ 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
Re: [Elecraft] HI CUR warning on K3
Yeah, I had to replace both the line isolator and the 4:1 balun at the feedpoint after about 2 years. 73, Pete N4ZR On 11/8/2023 11:02 AM, Tom Doligalski via Elecraft wrote: I have used one for years. That said, I have had to replace the line isolator several times! Also have one in the shack. Tom W4KX Sent from my iPad On Nov 8, 2023, at 10:49 AM,j...@kk9a.com wrote: I am not very familiar with a Carolina Windom but I believe it is just a horizonal wire fed off center. These types of antennas can have significant common mode current on the feedline. Perhaps there is more current on 40m than on 80m so it works on 80m. A resonant dipole with a choke may solve this HI CUR issue. John KK9a Pete Smith N4ZR wrote: I send a few characters of CW into my Carolina Windom on 40M and after a delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR warning, and the audio gain is reduced significantly. Touch the AF gain control and it instantly returns the gain to normal, but frequently the HI CURR warning returns over and over, without any additional transmissions. This sequence does not happen, even with 1500 watts, into my dummy load, nor does it happen on the same antenna on 80M, or on 20 meters on my tribander. I've read the HI CUR warning discussion on page 65 of the manual, but it doesn't seem relevant, because I don't have external speakers. The fact that it only happens when feeding an actual antenna on one band suggests RFI, but the fact that the HI CUR warning and gain reduction recur again and again long after any RF has me puzzled. Any suggestions gratefully accepted! -- 73, Pete N4ZR __ 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 tow...@mac.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 topete.n...@gmail.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
Re: [Elecraft] HI CUR warning on K3
I have used one for years. That said, I have had to replace the line isolator several times! Also have one in the shack. Tom W4KX Sent from my iPad > On Nov 8, 2023, at 10:49 AM, j...@kk9a.com wrote: > > I am not very familiar with a Carolina Windom but I believe it is just a > horizonal wire fed off center. These types of antennas can have significant > common mode current on the feedline. Perhaps there is more current on 40m > than on 80m so it works on 80m. > > A resonant dipole with a choke may solve this HI CUR issue. > > John KK9a > > > > > Pete Smith N4ZR wrote: > > I send a few characters of CW into my Carolina Windom on 40M and after a > delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR > warning, and the audio gain is reduced significantly. Touch the AF gain > control and it instantly returns the gain to normal, but frequently the > HI CURR warning returns over and over, without any additional > transmissions. This sequence does not happen, even with 1500 watts, > into my dummy load, nor does it happen on the same antenna on 80M, or on > 20 meters on my tribander. > > I've read the HI CUR warning discussion on page 65 of the manual, but it > doesn't seem relevant, because I don't have external speakers. The fact > that it only happens when feeding an actual antenna on one band > suggests RFI, but the fact that the HI CUR warning and gain reduction > recur again and again long after any RF has me puzzled. Any suggestions > gratefully accepted! > > -- > 73, Pete N4ZR > > __ > 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 w...@mac.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
Re: [Elecraft] HI CUR warning on K3
I am not very familiar with a Carolina Windom but I believe it is just a horizonal wire fed off center. These types of antennas can have significant common mode current on the feedline. Perhaps there is more current on 40m than on 80m so it works on 80m. A resonant dipole with a choke may solve this HI CUR issue. John KK9a Pete Smith N4ZR wrote: I send a few characters of CW into my Carolina Windom on 40M and after a delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR warning, and the audio gain is reduced significantly. Touch the AF gain control and it instantly returns the gain to normal, but frequently the HI CURR warning returns over and over, without any additional transmissions. This sequence does not happen, even with 1500 watts, into my dummy load, nor does it happen on the same antenna on 80M, or on 20 meters on my tribander. I've read the HI CUR warning discussion on page 65 of the manual, but it doesn't seem relevant, because I don't have external speakers. The fact that it only happens when feeding an actual antenna on one band suggests RFI, but the fact that the HI CUR warning and gain reduction recur again and again long after any RF has me puzzled. Any suggestions gratefully accepted! -- 73, Pete N4ZR __ 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
Re: [Elecraft] HI CUR warning on K3
Pete, The first thing to check for a HI CUR warning is the power supply voltage under full transmit load. If it is low, it will cause a HI CUR condition. The other thing that could cause it is a problem in the T/R switch or Low Pass Filter - the fact that it continues into an RX cycle points to that possibility. 73, Don W3FPR On 11/7/2023 10:31 AM, Pete Smith N4ZR wrote: I send a few characters of CW into my Carolina Windom on 40M and after a delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR warning, and the audio gain is reduced significantly. Touch the AF gain control and it instantly returns the gain to normal, but frequently the HI CURR warning returns over and over, without any additional transmissions. This sequence does not happen, even with 1500 watts, into my dummy load, nor does it happen on the same antenna on 80M, or on 20 meters on my tribander. I've read the HI CUR warning discussion on page 65 of the manual, but it doesn't seem relevant, because I don't have external speakers. The fact that it only happens when feeding an actual antenna on one band suggests RFI, but the fact that the HI CUR warning and gain reduction recur again and again long after any RF has me puzzled. Any suggestions gratefully accepted! __ 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
[Elecraft] HI CUR warning on K3
I send a few characters of CW into my Carolina Windom on 40M and after a delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR warning, and the audio gain is reduced significantly. Touch the AF gain control and it instantly returns the gain to normal, but frequently the HI CURR warning returns over and over, without any additional transmissions. This sequence does not happen, even with 1500 watts, into my dummy load, nor does it happen on the same antenna on 80M, or on 20 meters on my tribander. I've read the HI CUR warning discussion on page 65 of the manual, but it doesn't seem relevant, because I don't have external speakers. The fact that it only happens when feeding an actual antenna on one band suggests RFI, but the fact that the HI CUR warning and gain reduction recur again and again long after any RF has me puzzled. Any suggestions gratefully accepted! -- 73, Pete N4ZR __ 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
