[Elecraft] KX3 VSWR problem
My last post might have been too long, so I'll try again - just the facts: Equipment: KX3 S/N 7210, FW 02.25 Problem: 6M band -> VSWR 1.8:1 (KX3 meter) on 50ohm load connected directly to ant connector (no cable). ATU - bypass Load verified good. All other bands good. ATU will match to 1:1 if enabled and tune requested. After ATU match, 25ohm load yields 2:1 (KX3 meter test - OK). MSG to Elecraft support unanswered (which seems uncharacteristic, based on rep) Looking for input on how to identify/fix problem. Thanks, Steve, WD4SDC. -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809.html Sent from the Elecraft mailing list archive at Nabble.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] KX3 VSWR problem
WD4SDC wrote > Equipment: > KX3 S/N 7210, FW 02.25 > > Problem: > 6M band -> VSWR 1.8:1 (KX3 meter) on 50ohm load connected directly to ant > connector (no cable). > > MSG to Elecraft support unanswered (which seems uncharacteristic, based on > rep) UPDATE: Just to complete this for anyone searching this problem Elecraft support did respond. I had sent the msg to supp...@elecraft.com and not the correct address which is k3supp...@elecraft.com. The test was to disconnect the remove the ATU board and connect the RF board directly to the antenna port - which worked OK - 1.2:1. With ATU installed and auto-tuned, I get 10 watts delivered to the load, so in my case the bypass VSWR is little high, but not really a concern. Since the ATU *is* installed, just tune it and everything works fine. Steve. -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809p7610774.html Sent from the Elecraft mailing list archive at Nabble.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] KX3 VSWR problem
WD4SDC wrote Equipment: KX3 S/N 7210, FW 02.25 Problem: 6M band -> VSWR 1.8:1 (KX3 meter) on 50ohm load connected directly to ant connector (no cable). Followed by this UPDATE: The test was to disconnect the remove the ATU board and connect the RF board directly to the antenna port - which worked OK - 1.2:1. With ATU installed and auto-tuned, I get 10 watts delivered to the load, so in my case the bypass VSWR is little high, but not really a concern. Since the ATU *is* installed, just tune it and everything works fine. I'm not sure I understand..are you saying with the ATU removed the VSWR is 1.2:1 and with it installed but not tuned it's 1.8:1 until the ATU "kicks in and does its job??? 72 de Jim R. K9JWV __ 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] KX3 VSWR problem
Jim Rodenkirch wrote > > I'm not sure I understand..are you saying with the ATU removed the > VSWR is 1.2:1 and with it > > installed but not tuned it's 1.8:1 until the ATU "kicks in and does its > job??? Hi Jim, Sorry for the confusion. I'll pull everything into this post to put it in the correct context: Problem: 6M band -> VSWR 1.8:1 (KX3 meter) on 50ohm load connected directly to ant connector (no cable). ATU - bypass mode Load verified good. All other bands good. ATU will match to 1:1 if enabled and tune requested. After ATU match, 25ohm load yields 2:1 (KX3 VSWR meter test - OK). So the issue was that the ATU in bypass mode on 6M into good load gives a 1.8:1 VSWR. Working with Elecraft support, I removed the ATU board to check VSWR w/o the ATU in the line. That checked good 1.2:1. The ATU in bypass mode on 6M does not quite function as a 50 ohm transmission line. For my particular unit, it was higher than expected. 1.4:1 is considered OK. If the ATU is enabled and tune is engaged, it has no problem matching the output stage to the load and delivering rated power. So, operationally not really an issue. Just leave the ATU enabled and tuned. The reason for going into bypass mode was to perform a TX gain cal procedure, which specifies the ATU must be set to bypass. I used the KX3 utility to do this and it sets the ATU to bypass and steps thru each band. When it got to 6M, it failed - probably because the foldback circuit was kicking in @ 1.8:1 and/or the output stage can't deliver the 6 watts need to complete the cal into that mismatch. Doing the cal manually with the ATU on and matched for 6M band works fine. Hopefully, this provides a more useful note for anyone else that may have a similar issue. Trying to contribute back to the list - as I have learned a lot using this resource. Steve WD4SDC -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809p7610821.html Sent from the Elecraft mailing list archive at Nabble.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] KX3 VSWR problem
WD4SDC wrote > MSG to Elecraft support unanswered (which seems uncharacteristic, based on > rep) I was contacted by elecraft support shortly after this post. Will be running some tests per their advice. Steve WD4SDC -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809p7608813.html Sent from the Elecraft mailing list archive at Nabble.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] KX3 VSWR problem
Could it be your load is not rated to 50 MHZ ? Some are only good to 30 MHZ. On Wednesday, October 7, 2015, WD4SDC wrote: > WD4SDC wrote > > MSG to Elecraft support unanswered (which seems uncharacteristic, based > on > > rep) > > I was contacted by elecraft support shortly after this post. Will be > running some tests per their advice. > > Steve WD4SDC > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809p7608813.html > Sent from the Elecraft mailing list archive at Nabble.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 rickw...@gmail.com > -- Rick, W8ZT Sent from Gmail Mobile __ 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] KX3 VSWR problem
Rick Robinson wrote > Could it be your load is not rated to 50 MHZ ? Some are only good to 30 > MHZ. Hi Rick. Good point. I should have included my load spec w/ the "facts": I'm using a Narda 40W DC->12GHz w/ N->BNC adapter I borrowed at work. And verified it @ 50MHz - just because sometimes test equipment gets abused ;) Steve. -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-VSWR-problem-tp7608809p7608851.html Sent from the Elecraft mailing list archive at Nabble.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] KX3 VSWR problem (WD4SDC)
Steve: Is it possible your dummy load is not 50 ohms at 6M? In other words, is your dummy load designed to work at VHF frequencies? Maybe it's only designed for HF frequencies. Just a thought, but it could possibly explain your problem. 73, John AA0VE Jim Rodenkirch wrote I'm not sure I understand..are you saying with the ATU removed the VSWR is 1.2:1 and with it installed but not tuned it's 1.8:1 until the ATU "kicks in and does its job??? Hi Jim, Sorry for the confusion. I'll pull everything into this post to put it in the correct context: Problem: 6M band -> VSWR 1.8:1 (KX3 meter) on 50ohm load connected directly to ant connector (no cable). ATU - bypass mode Load verified good. All other bands good. ATU will match to 1:1 if enabled and tune requested. After ATU match, 25ohm load yields 2:1 (KX3 VSWR meter test - OK). So the issue was that the ATU in bypass mode on 6M into good load gives a 1.8:1 VSWR. Working with Elecraft support, I removed the ATU board to check VSWR w/o the ATU in the line. That checked good 1.2:1. The ATU in bypass mode on 6M does not quite function as a 50 ohm transmission line. For my particular unit, it was higher than expected. 1.4:1 is considered OK. If the ATU is enabled and tune is engaged, it has no problem matching the output stage to the load and delivering rated power. So, operationally not really an issue. Just leave the ATU enabled and tuned. The reason for going into bypass mode was to perform a TX gain cal procedure, which specifies the ATU must be set to bypass. I used the KX3 utility to do this and it sets the ATU to bypass and steps thru each band. When it got to 6M, it failed - probably because the foldback circuit was kicking in @ 1.8:1 and/or the output stage can't deliver the 6 watts need to complete the cal into that mismatch. Doing the cal manually with the ATU on and matched for 6M band works fine. Hopefully, this provides a more useful note for anyone else that may have a similar issue. Trying to contribute back to the list - as I have learned a lot using this resource. Steve WD4SDC __ 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] KX3 VSWR problem (WD4SDC)
Hi John, Resonable question. The load was a Narda type N 20W dry load good from DC - 12GHz - borrowed from work;) And I did test it just to make sure someone else did not "abuse" it (bench test equipment). Also tested the N->BNC adapter. Trust, but verify your test equipmentgood advice. 73, Steve. Steve: Is it possible your dummy load is not 50 ohms at 6M? In other words, is your dummy load designed to work at VHF frequencies? Maybe it's only designed for HF frequencies. Just a thought, but it could possibly explain your problem. 73, John AA0VE -- View this message in context: http://elecraft.365791.n2.nabble.com/Re-KX3-VSWR-problem-WD4SDC-tp7610860p7610870.html Sent from the Elecraft mailing list archive at Nabble.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
