Re: [Elecraft] KAT 500 Loses Match
The only thing that has a flat 1:1 SWR from 80m to 6m is a good quality dummy load. Dave AB7E On 1/12/2024 10:28 PM, Michael Reynolds, NO6O wrote: Greetings, I joined this list today, after sending a message to Elecraft support, describing a similar problem. I have an Icom IC-7610, with the KPA500 and KAT500, and my SWR spontaneously climbs into the red sometimes during transmissions. It takes some effort to correct it, and I typically lose a QSO in the process. The relays go nuts trying to re-tune, and sometimes produces a fault condition. Usually, I can correct it by restarting both the amplifier and tuner. I have a Comet CHA-250HD, which has a almost a flat 1.1 SWR from 80m to 6m. I don't need a tuner while barefoot. However, when I first hooked up the KPA500, the SWR was not flat, and added the KAT500 this week, which led to my SWR issue. I hope the cause and resolution can be determined. Michael NO6O __ 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] KAT 500 Loses Match
I have a CHA-250B antenna, but it is not currently up. This antenna is only rated for 250W SSB which is probably 100W on CW or a digital mode. I think this antenna has a matching network and at higher powers will saturate the cores causing SWR to rise out of control. Same thing happens for me with an EFHW antenna on 80M at 500W. This is a limitation with core matching networks. Bruce, WB6IZG On Fri, Jan 12, 2024 at 9:29 PM Michael Reynolds, NO6O wrote: > Greetings, > > I joined this list today, after sending a message to Elecraft support, > describing a similar problem. I have an Icom IC-7610, with the KPA500 > and KAT500, and my SWR spontaneously climbs into the red sometimes > during transmissions. It takes some effort to correct it, and I > typically lose a QSO in the process. The relays go nuts trying to > re-tune, and sometimes produces a fault condition. Usually, I can > correct it by restarting both the amplifier and tuner. I have a Comet > CHA-250HD, which has a almost a flat 1.1 SWR from 80m to 6m. I don't > need a tuner while barefoot. However, when I first hooked up the > KPA500, the SWR was not flat, and added the KAT500 this week, which led > to my SWR issue. > > I hope the cause and resolution can be determined. > > Michael > NO6O > > > __ 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] KAT 500 Loses Match
Your situation sounds like 1) something is heating up and changing value or 2) something is arcing and changing value. Are you using a balun or choke that is underrated? Ken WA8JXM On 1/13/2024 12:28 AM, Michael Reynolds, NO6O wrote: Greetings, I joined this list today, after sending a message to Elecraft support, describing a similar problem. I have an Icom IC-7610, with the KPA500 and KAT500, and my SWR spontaneously climbs into the red sometimes during transmissions. It takes some effort to correct it, and I typically lose a QSO in the process. The relays go nuts trying to re-tune, and sometimes produces a fault condition. Usually, I can correct it by restarting both the amplifier and tuner. I have a Comet CHA-250HD, which has a almost a flat 1.1 SWR from 80m to 6m. I don't need a tuner while barefoot. However, when I first hooked up the KPA500, the SWR was not flat, and added the KAT500 this week, which led to my SWR issue. I hope the cause and resolution can be determined. Michael NO6O m __ 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] KAT 500 Loses Match
Greetings, I joined this list today, after sending a message to Elecraft support, describing a similar problem. I have an Icom IC-7610, with the KPA500 and KAT500, and my SWR spontaneously climbs into the red sometimes during transmissions. It takes some effort to correct it, and I typically lose a QSO in the process. The relays go nuts trying to re-tune, and sometimes produces a fault condition. Usually, I can correct it by restarting both the amplifier and tuner. I have a Comet CHA-250HD, which has a almost a flat 1.1 SWR from 80m to 6m. I don't need a tuner while barefoot. However, when I first hooked up the KPA500, the SWR was not flat, and added the KAT500 this week, which led to my SWR issue. I hope the cause and resolution can be determined. Michael NO6O On 2024-01-12 10:36 PM, Bill Johnson wrote: Good advice Bill K9YEQ From: elecraft-boun...@mailman.qth.net on behalf of Ken WA8JXM Sent: Friday, January 12, 2024 5:52:52 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KAT 500 Loses Match It's possible that something is arcing and, of course changing the tuning. Do you have the internal tuner in the K4? If so, does it behave the same way? Why do you have the amplifier running? 30m is as restricted power band. If you leave the amp and tuner out of the circuit and transmit with the K4 directly, does the SWR meter stay steady, or does it fluctuate at full power? Ken WA8JXM Why is the amplifier connected? 30m is a restricted powerband. On 1/12/2024 4:46 PM, Paul Ecker wrote: I am experiencing a new problem for me, with my KAT 500. So far I've noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz segments on 30M. Setup is K4D, KAT 500 & KPA 500. Win 10 pc. Running CW, I can start transmitting and all is fine- my LP100A is showing 1.2 SWR and am getting max power out of the radio. Then all of sudden the SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if I start transmitting again – pwr out is only about 10 W at that new match, and eventually the tuner becomes untuned again. Sometimes, it will then hold the tune but still only getting abt 9-10w power out. The issue occurs with KPA500 both on and off. Does this sound like a KAT 500 problem or maybe an RFI problem. 73 Paul w2eck __ 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 k9...@live.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 mich...@no6o.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] KAT 500 Loses Match
I just realized you said 30m. Why are you running the amplifier ("max
power") on 30m??
Dave AB7E
On 1/12/2024 2:46 PM, Paul Ecker wrote:
I am experiencing a new problem for me, with my KAT 500. So far I've
noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR
of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz
segments on 30M.
Setup is K4D, KAT 500 & KPA 500. Win 10 pc.
Running CW, I can start transmitting and all is fine- my LP100A is showing
1.2 SWR and am getting max power out of the radio. Then all of sudden the
SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if
I start transmitting again – pwr out is only about 10 W at that new match,
and eventually the tuner becomes untuned again. Sometimes, it will then
hold the tune but still only getting abt 9-10w power out. The issue occurs
with KPA500 both on and off.
Does this sound like a KAT 500 problem or maybe an RFI problem.
73 Paul
w2eck
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Re: [Elecraft] KAT 500 Loses Match
Good advice Bill K9YEQ From: elecraft-boun...@mailman.qth.net on behalf of Ken WA8JXM Sent: Friday, January 12, 2024 5:52:52 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KAT 500 Loses Match It's possible that something is arcing and, of course changing the tuning. Do you have the internal tuner in the K4? If so, does it behave the same way? Why do you have the amplifier running? 30m is as restricted power band. If you leave the amp and tuner out of the circuit and transmit with the K4 directly, does the SWR meter stay steady, or does it fluctuate at full power? Ken WA8JXM Why is the amplifier connected? 30m is a restricted powerband. On 1/12/2024 4:46 PM, Paul Ecker wrote: > I am experiencing a new problem for me, with my KAT 500. So far I've > noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR > of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz > segments on 30M. > > Setup is K4D, KAT 500 & KPA 500. Win 10 pc. > > Running CW, I can start transmitting and all is fine- my LP100A is showing > 1.2 SWR and am getting max power out of the radio. Then all of sudden the > SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if > I start transmitting again – pwr out is only about 10 W at that new match, > and eventually the tuner becomes untuned again. Sometimes, it will then > hold the tune but still only getting abt 9-10w power out. The issue occurs > with KPA500 both on and off. > > Does this sound like a KAT 500 problem or maybe an RFI problem. > > > 73 Paul > > w2eck __ 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 k9...@live.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
[Elecraft] KAT 500 Loses Match
Thanks to all for the advice and suggestions. Will be out of pocket for a day or so, but you have given me lots of areas to checkout and troubleshoot. Will let you know what I find out. 73 Paul w2eck __ 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] KAT 500 Loses Match
It's possible that something is arcing and, of course changing the tuning. Do you have the internal tuner in the K4? If so, does it behave the same way? Why do you have the amplifier running? 30m is as restricted power band. If you leave the amp and tuner out of the circuit and transmit with the K4 directly, does the SWR meter stay steady, or does it fluctuate at full power? Ken WA8JXM Why is the amplifier connected? 30m is a restricted powerband. On 1/12/2024 4:46 PM, Paul Ecker wrote: I am experiencing a new problem for me, with my KAT 500. So far I've noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz segments on 30M. Setup is K4D, KAT 500 & KPA 500. Win 10 pc. Running CW, I can start transmitting and all is fine- my LP100A is showing 1.2 SWR and am getting max power out of the radio. Then all of sudden the SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if I start transmitting again – pwr out is only about 10 W at that new match, and eventually the tuner becomes untuned again. Sometimes, it will then hold the tune but still only getting abt 9-10w power out. The issue occurs with KPA500 both on and off. Does this sound like a KAT 500 problem or maybe an RFI problem. 73 Paul w2eck __ 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] KAT 500 Loses Match
It sounds like a bad connection or arc-over in a connector, cable, balun, etc. after the KAT500. I had a similar issue that drove me nuts for weeks until I found a corroded solder connection in a balun at the feedpoint of an antenna. It does not sound like an RFI issue. 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco On 12/01/2024 23:46, Paul Ecker wrote: I am experiencing a new problem for me, with my KAT 500. So far I've noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz segments on 30M. Setup is K4D, KAT 500 & KPA 500. Win 10 pc. Running CW, I can start transmitting and all is fine- my LP100A is showing 1.2 SWR and am getting max power out of the radio. Then all of sudden the SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if I start transmitting again – pwr out is only about 10 W at that new match, and eventually the tuner becomes untuned again. Sometimes, it will then hold the tune but still only getting abt 9-10w power out. The issue occurs with KPA500 both on and off. Does this sound like a KAT 500 problem or maybe an RFI problem. 73 Paul w2eck __ 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 tok2vco@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] KAT 500 Loses Match
__ 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] KAT 500 Loses Match
That sounds EXACTLY like an arc over somewhere past your KAT500. Could be a connector, the coax, the connection to the dipole, or any similar spot, but my bet would be the connection to the connector or the connector itself. Dave AB7E On 1/12/2024 2:46 PM, Paul Ecker wrote: I am experiencing a new problem for me, with my KAT 500. So far I've noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz segments on 30M. Setup is K4D, KAT 500 & KPA 500. Win 10 pc. Running CW, I can start transmitting and all is fine- my LP100A is showing 1.2 SWR and am getting max power out of the radio. Then all of sudden the SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if I start transmitting again – pwr out is only about 10 W at that new match, and eventually the tuner becomes untuned again. Sometimes, it will then hold the tune but still only getting abt 9-10w power out. The issue occurs with KPA500 both on and off. Does this sound like a KAT 500 problem or maybe an RFI problem. 73 Paul w2eck __ 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 toab7e...@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] KAT 500 Loses Match
I would first check all connections. If you are running 500 w then any bad connection can create your issue, not the amp. Bill K9YEQ From: elecraft-boun...@mailman.qth.net on behalf of Paul Ecker Sent: Friday, January 12, 2024 3:30:16 PM To: Ken Winterling Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] KAT 500 Loses Match Ken With the KAT connected to a dummy load on the 30M port, I don't see the problem re-occur. The SWR measured outside prior to entering the box with a polyphaser is low. So some type of problem is between the KAT and the connection box outside?? 73 & tnx for help Paul w2eck On Fri, Jan 12, 2024 at 5:13 PM Ken Winterling wrote: > Paul, > > Connect a dummy load in place of the antenna and repeat your testing. > This will eliminate the antenna as a possible source of RFI. > > Report the results of your tests, > > GL! > > *Ken* > *WA2LBI* > > > > > On Fri, Jan 12, 2024 at 4:47 PM Paul Ecker wrote: > >> I am experiencing a new problem for me, with my KAT 500. So far I've >> noticed this issue on 30M. I am using a dipole cut only for 30M with an >> SWR >> of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz >> segments on 30M. >> >> Setup is K4D, KAT 500 & KPA 500. Win 10 pc. >> >> Running CW, I can start transmitting and all is fine- my LP100A is showing >> 1.2 SWR and am getting max power out of the radio. Then all of sudden the >> SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if >> I start transmitting again – pwr out is only about 10 W at that new match, >> and eventually the tuner becomes untuned again. Sometimes, it will then >> hold the tune but still only getting abt 9-10w power out. The issue occurs >> with KPA500 both on and off. >> >> Does this sound like a KAT 500 problem or maybe an RFI problem. >> >> >> 73 Paul >> >> w2eck >> __ >> 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 wa2...@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 k9...@live.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] KAT 500 Loses Match
Ken With the KAT connected to a dummy load on the 30M port, I don't see the problem re-occur. The SWR measured outside prior to entering the box with a polyphaser is low. So some type of problem is between the KAT and the connection box outside?? 73 & tnx for help Paul w2eck On Fri, Jan 12, 2024 at 5:13 PM Ken Winterling wrote: > Paul, > > Connect a dummy load in place of the antenna and repeat your testing. > This will eliminate the antenna as a possible source of RFI. > > Report the results of your tests, > > GL! > > *Ken* > *WA2LBI* > > > > > On Fri, Jan 12, 2024 at 4:47 PM Paul Ecker wrote: > >> I am experiencing a new problem for me, with my KAT 500. So far I've >> noticed this issue on 30M. I am using a dipole cut only for 30M with an >> SWR >> of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz >> segments on 30M. >> >> Setup is K4D, KAT 500 & KPA 500. Win 10 pc. >> >> Running CW, I can start transmitting and all is fine- my LP100A is showing >> 1.2 SWR and am getting max power out of the radio. Then all of sudden the >> SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if >> I start transmitting again – pwr out is only about 10 W at that new match, >> and eventually the tuner becomes untuned again. Sometimes, it will then >> hold the tune but still only getting abt 9-10w power out. The issue occurs >> with KPA500 both on and off. >> >> Does this sound like a KAT 500 problem or maybe an RFI problem. >> >> >> 73 Paul >> >> w2eck >> __ >> 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 wa2...@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] KAT 500 Loses Match
On 1/12/2024 1:46 PM, Paul Ecker wrote: Does this sound like a KAT 500 problem or maybe an RFI problem. It sounds like a problem somewhere after the output of the power amp, including all interconnecting cables, the feedline, and the antenna. Common problems are loose connectors and/or adapters, junk connectors and/or adapters, connectors poorly installed, moisture somewhere in that path, some defect in the antenna. The vast majority of connectors and adapters sold to hams are junk. If it isn't stamped "Amphenol" or with a MIL-spec number, it's probably junk. 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] KAT 500 Loses Match
Paul, Connect a dummy load in place of the antenna and repeat your testing. This will eliminate the antenna as a possible source of RFI. Report the results of your tests, GL! *Ken* *WA2LBI* On Fri, Jan 12, 2024 at 4:47 PM Paul Ecker wrote: > I am experiencing a new problem for me, with my KAT 500. So far I've > noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR > of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz > segments on 30M. > > Setup is K4D, KAT 500 & KPA 500. Win 10 pc. > > Running CW, I can start transmitting and all is fine- my LP100A is showing > 1.2 SWR and am getting max power out of the radio. Then all of sudden the > SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if > I start transmitting again – pwr out is only about 10 W at that new match, > and eventually the tuner becomes untuned again. Sometimes, it will then > hold the tune but still only getting abt 9-10w power out. The issue occurs > with KPA500 both on and off. > > Does this sound like a KAT 500 problem or maybe an RFI problem. > > > 73 Paul > > w2eck > __ > 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 wa2...@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
[Elecraft] KAT 500 Loses Match
I am experiencing a new problem for me, with my KAT 500. So far I've noticed this issue on 30M. I am using a dipole cut only for 30M with an SWR of 1.2 to 1.3 max SWR across the band. I “trained the tuner” at 20khz segments on 30M. Setup is K4D, KAT 500 & KPA 500. Win 10 pc. Running CW, I can start transmitting and all is fine- my LP100A is showing 1.2 SWR and am getting max power out of the radio. Then all of sudden the SWR jumps to >9.0. The KAT starts chattering and finds a new match. But if I start transmitting again – pwr out is only about 10 W at that new match, and eventually the tuner becomes untuned again. Sometimes, it will then hold the tune but still only getting abt 9-10w power out. The issue occurs with KPA500 both on and off. Does this sound like a KAT 500 problem or maybe an RFI problem. 73 Paul w2eck __ 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] K3+KPA500+KAT500 RFI Revisited
On 1/12/2024 12:18 PM, Jeff Wandling wrote: Seems like a while ago I was troubleshooting the RFI problem between the equipment. Is everything in your home and your station properly bonded and grounded? Is every chassis on your operating desk bonded together? Is the operating desk common point bonded to all the grounds in your home? http://k9yc.com/GroundingAndAudio.pdf Are there arrestors on all of your antennas, and are they bonded to the other grounds? Are there serious ferrite chokes at the feedpoint of every antenna? A serious ferrite choke is one of these. http://k9yc.com/2018Cookbook.pdf If you're using any form of end-fed antenna, including a vertical, does it have radials or a counterpoise? There's one other mechanism that I'm aware of, having been a beta tester for KA500 years ago. When running two radios with amps and tuners, their frequency-detecting circuitry for station #1 while in receive can get enough RF from station #2 transmitting to switch to station #2's band. This depends primarily on how close the antennas for the two stations are to each other and how much power we're running. This is very old info, from the early days of KAT500, and may have been minimized by later versions of firmware. 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] K3+KPA500+KAT500 RFI Revisited
Before replacing cables or adding ferrites, I would make sure that all the chassis are bonded together with short runs of heavy gauge wire. Differences in ground potentials between equipment can make a mess of things. For more info, get the book on grounding and bonding from the ARRL. https://www.arrl.org/grounding-and-bonding-for-the-amateur wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Jan 12, 2024, at 12:18 PM, Jeff Wandling wrote: > > Dear Elecraft aficionados: > > The symptom is KPA switching bands during Tx. > > Seems like a while ago I was troubleshooting the RFI problem between the > equipment. > > K3 + KPA500 + KAT500 > > Using the "enhanced" configuration where serial cable between the K3 to KAT > to KPA assisted in communicating band changes as well as key-down event and > so on. > > I own two KPA-500's. Both are less than 6mo old. > > Let me refer to them as KPA-1 and KPA-2. KPA-1 is in the hands of Elecraft > for repair. It worked flawlessly (until needing repair), but the RFI issue I > will write about did not exist when that KPA-1 was in the chain. > > KPA-2 was purchased in December as a backup. Since putting KPA-2 in-line, the > RFI problems I will describe have gone unresolved. > > Scenario is with KPA-2 in-line. > > Even running tiny power (< 10W, <15 W) I can routinely and 100% reproduce the > problem where the BCD data in the AUX line that carries the information about > which band the KPA should be set on will change during Tx. > > For example I can put KAT into MAN, put KPA in bypass. Tune the antenna via > K3 and witness the search resolve to a 1:1 on the SWR. That sometimes will > trigger the effect -- I can see in the KPA, even in bypass that the band the > KPA is set on is changed from the band the K3 is set on. Even more insidious > is that if the KPA winds up on a different band after the tune (or after > "VVV" CW testing after tune), that pressing the band button on the KPA to > bring it back does not bring the KPA back to the right band. It is as if the > KPA has two states of band-awareness.. The awareness of the band displayed in > the LCD and the band that the input is set for. > > Here's an example: > K3 on 40m > Tune per usual (KAT MANUAL, KPA Bypass) > KPA remains on 40m. > K3 power output 14W > Then put the KPA into Operate > Tap "VVV" out on the key. > Witness the KPA operate but then switch band to 30m or 17m or 20m, etc.. (not > expected) > Then on the KPA tap (Band) 7 (for the 40m band) and nothing happens (not > expected) > Tap on the KPA 14 then the whole chain switches to 20m (expected) > > Suppose the TUNE did not yield a band-switch during Tx, repeating the test > but this time putting the KPA into Operate after the tune is sure-fire going > to cause the bandswitch. > > (I configured the KPA to go to Bypass in the event of a band-change event in > order to have some sense of protection while the key-down test Tx occurs). > > That's the scenario where after Tx the KPA is out of sync with the K3. > Whether or not the KPA is attempting to frequency-count is not evident, the > KPA:RADIO setting is "K3" which means leverage the BCD data from the K3 > vis-a-vis the KAT path. > > I can replicate this band-inconsistency at will. I don't think I can safely > operate the equipment if the BCD encoded band data is fluctuating during Tx. > What would happen if I switched bands (N1MM) and hit the keyer and the KPA > got confused on the last Tx? Magic smoke I imagine. > > Only happened with KPA-2 not KPA-1. But I'm wondering if KPA-1 suffered a > catastrophe caused by this scenario and I didn't notice the clicking > band-switch because I had not expected it to switch bands during Tx. > > What have I done to remedy? I think I've tried everything but obviously I > have a gap -- otherwise I'd have solved this problem. > > - New coax between everything. > - Shorter or longer coax, different coax (RG-213, 8X, LMR-240, etc..) > - Tighter loops (6 -8") when there is excess coax or lazy big loops where > there is excess coax. > - New connectors/adapters (Yes, Amphenol) > - Re-route coax different ways. Avoid this, that and the other, etc.. > Permutations of routing. > - Move and adjust placement of equipment. KAT near the KPA, KAT away from the > KPA, both near or away from the K3, etc.. > - Chokes between things. K3 to KPA, KPA to KAT, KAT to antenna system > - Non-bleeding chokes, bleeding chokes. > - Ferrite on serial cables, more ferrite, insane amounts of ferrite, or zero > ferrite > - Move the position of serial cables above, below, up, down, left, right. > > I haven't got to the point of putting little tangerines on altars and burning > incense. I'm trying to keep a positive mood while part of me wants to take up > the art of Bonsai and raking the sand. > > Obviously RFI is a likely culprit, but I'll be damned if I can figure out > where it is -- or rather why it would be
[Elecraft] K3+KPA500+KAT500 RFI Revisited
Dear Elecraft aficionados: The symptom is KPA switching bands during Tx. Seems like a while ago I was troubleshooting the RFI problem between the equipment. K3 + KPA500 + KAT500 Using the "enhanced" configuration where serial cable between the K3 to KAT to KPA assisted in communicating band changes as well as key-down event and so on. I own two KPA-500's. Both are less than 6mo old. Let me refer to them as KPA-1 and KPA-2. KPA-1 is in the hands of Elecraft for repair. It worked flawlessly (until needing repair), but the RFI issue I will write about did not exist when that KPA-1 was in the chain. KPA-2 was purchased in December as a backup. Since putting KPA-2 in-line, the RFI problems I will describe have gone unresolved. Scenario is with KPA-2 in-line. Even running tiny power (< 10W, <15 W) I can routinely and 100% reproduce the problem where the BCD data in the AUX line that carries the information about which band the KPA should be set on will change during Tx. For example I can put KAT into MAN, put KPA in bypass. Tune the antenna via K3 and witness the search resolve to a 1:1 on the SWR. That sometimes will trigger the effect -- I can see in the KPA, even in bypass that the band the KPA is set on is changed from the band the K3 is set on. Even more insidious is that if the KPA winds up on a different band after the tune (or after "VVV" CW testing after tune), that pressing the band button on the KPA to bring it back does not bring the KPA back to the right band. It is as if the KPA has two states of band-awareness.. The awareness of the band displayed in the LCD and the band that the input is set for. Here's an example: K3 on 40m Tune per usual (KAT MANUAL, KPA Bypass) KPA remains on 40m. K3 power output 14W Then put the KPA into Operate Tap "VVV" out on the key. Witness the KPA operate but then switch band to 30m or 17m or 20m, etc.. (not expected) Then on the KPA tap (Band) 7 (for the 40m band) and nothing happens (not expected) Tap on the KPA 14 then the whole chain switches to 20m (expected) Suppose the TUNE did not yield a band-switch during Tx, repeating the test but this time putting the KPA into Operate after the tune is sure-fire going to cause the bandswitch. (I configured the KPA to go to Bypass in the event of a band-change event in order to have some sense of protection while the key-down test Tx occurs). That's the scenario where after Tx the KPA is out of sync with the K3. Whether or not the KPA is attempting to frequency-count is not evident, the KPA:RADIO setting is "K3" which means leverage the BCD data from the K3 vis-a-vis the KAT path. I can replicate this band-inconsistency at will. I don't think I can safely operate the equipment if the BCD encoded band data is fluctuating during Tx. What would happen if I switched bands (N1MM) and hit the keyer and the KPA got confused on the last Tx? Magic smoke I imagine. Only happened with KPA-2 not KPA-1. But I'm wondering if KPA-1 suffered a catastrophe caused by this scenario and I didn't notice the clicking band-switch because I had not expected it to switch bands during Tx. What have I done to remedy? I think I've tried everything but obviously I have a gap -- otherwise I'd have solved this problem. - New coax between everything. - Shorter or longer coax, different coax (RG-213, 8X, LMR-240, etc..) - Tighter loops (6 -8") when there is excess coax or lazy big loops where there is excess coax. - New connectors/adapters (Yes, Amphenol) - Re-route coax different ways. Avoid this, that and the other, etc.. Permutations of routing. - Move and adjust placement of equipment. KAT near the KPA, KAT away from the KPA, both near or away from the K3, etc.. - Chokes between things. K3 to KPA, KPA to KAT, KAT to antenna system - Non-bleeding chokes, bleeding chokes. - Ferrite on serial cables, more ferrite, insane amounts of ferrite, or zero ferrite - Move the position of serial cables above, below, up, down, left, right. I haven't got to the point of putting little tangerines on altars and burning incense. I'm trying to keep a positive mood while part of me wants to take up the art of Bonsai and raking the sand. Obviously RFI is a likely culprit, but I'll be damned if I can figure out where it is -- or rather why it would be -- affecting this given all of the mitigations attempted. But I'm always a student and looking for things that were/are not obvious at first. I'm almost to the point where I will take away the "enhanced" mode serial data path between the equipment and rely on the analog key-line between them and RF frequency-counter capabilities so that the KAT and the KPA are on the right band when I key-down. I just need to review the docs to make sure I have the KPA and the KAT setup to go "analog" rather than "KPA:RADIO = K3" mode. But the 'enhanced' mode is much more preferred since it is a K-line. Thoughts and suggestions welcome. Ping directly if you wish. Thanks! Jeff
