Re: [Elecraft] KAT 500 Loses Match
David, True but IIRC I was replying to a message where he said the SWR was flat through 6m. Usually, somewhere between 20m and 6m, receive losses do count. Ken WA8JXM On 1/14/2024 4:33 PM, David Woolley wrote: The receive part of the penalty, from a lossy antenna, only applies if the dominant noise source is after the point of attenuation. That's not generally true at HF. (I wonder if, at microwave frequencies, it is possible to use circulators and isolators to put passive losses in on only the transmit path.) __ 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
The receive part of the penalty, from a lossy antenna, only applies if the dominant noise source is after the point of attenuation. That's not generally true at HF. (I wonder if, at microwave frequencies, it is possible to use circulators and isolators to put passive losses in on only the transmit path.) -- David Woolley On 14/01/2024 05:16, Ken WA8JXM wrote: Unless its something like a log periodic, I think anything with those frequency/SWR specs can only do it with high resistive losses. It reminds me of the HF dipole B makes for the military: it is designed to appear to have a low SWR by having 3 db of resistive losses. The military considered that an acceptable design. Remember, antenna losses affect TX and RX, so that's 6 db system loss. __ 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
If you were putting 200 watts into it on FT8 that's almost three times the manufacturers rating and you're lucky you didn't fry it. Dave AB7E On 1/14/2024 1:18 PM, Michael Reynolds, NO6O wrote: Actually, I was only putting around 200 into the antenna, and it's doing fine. I've been continuing to make digital contacts without the amp and tuner. The antenna works great for me. I reached 50 countries during the past few weeks of testing. Fortunately, I fully understand what was going wrong. Michael, NO6O On 2024-01-14 1:03 PM, David Gilbert wrote: Fully agree. The specs for the CHA-250B say a maximum of 75 watts for digital modes ... i.e., continuous duty modes. That pretty much says what the actual heat dissipation capability is. If he was trying to put 500 watts into his antenna in almost any mode, it is probably toast ... figuratively and literally. Dave AB7E On 1/14/2024 8:17 AM, Morgan Bailey wrote: The Cha250 b is NOT an antenna capable of greater than 100 watts for any length of time. It is a 5:1 unun hooked to a 23 foot aluminum radiator. It needs to be 30 feet in the air and if that happens it will function like a vertical OCFD. Still it is only good for 100 watts. When running a tuner with the KAT500 and KPA500 you are heating up the puny unun and the cores are totally being fried. Plus the reactance probably is generating high voltage on the short radiator causing arcs across any of the many connections inside the matching section. A guy fried a base section and I have it in the garage. That is your problem. I have owned 2 of the antennas and as such they work in a pinch and work well for fast POTA activation with 100 watts but other than that they are pretty much a megga compromise antenna. You would be way better off with a 998 mfg remote tuner and a 43 foot vertical over a radial field. Check out the Zero5 antennas for the cheapest durable 43foot vertical solution. 73, Morgan NJ8M BS + MS + $2.98 = COFFEE Real Life Experience = Priceless, says the man who set his back yard on fire with a breadboard tuner loading a 160 meter inverted L with 1000 watts. LOL __ 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 ab7e...@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
Actually, I was only putting around 200 into the antenna, and it's doing fine. I've been continuing to make digital contacts without the amp and tuner. The antenna works great for me. I reached 50 countries during the past few weeks of testing. Fortunately, I fully understand what was going wrong. Michael, NO6O On 2024-01-14 1:03 PM, David Gilbert wrote: Fully agree. The specs for the CHA-250B say a maximum of 75 watts for digital modes ... i.e., continuous duty modes. That pretty much says what the actual heat dissipation capability is. If he was trying to put 500 watts into his antenna in almost any mode, it is probably toast ... figuratively and literally. Dave AB7E On 1/14/2024 8:17 AM, Morgan Bailey wrote: The Cha250 b is NOT an antenna capable of greater than 100 watts for any length of time. It is a 5:1 unun hooked to a 23 foot aluminum radiator. It needs to be 30 feet in the air and if that happens it will function like a vertical OCFD. Still it is only good for 100 watts. When running a tuner with the KAT500 and KPA500 you are heating up the puny unun and the cores are totally being fried. Plus the reactance probably is generating high voltage on the short radiator causing arcs across any of the many connections inside the matching section. A guy fried a base section and I have it in the garage. That is your problem. I have owned 2 of the antennas and as such they work in a pinch and work well for fast POTA activation with 100 watts but other than that they are pretty much a megga compromise antenna. You would be way better off with a 998 mfg remote tuner and a 43 foot vertical over a radial field. Check out the Zero5 antennas for the cheapest durable 43foot vertical solution. 73, Morgan NJ8M BS + MS + $2.98 = COFFEE Real Life Experience = Priceless, says the man who set his back yard on fire with a breadboard tuner loading a 160 meter inverted L with 1000 watts. LOL __ 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
Fully agree. The specs for the CHA-250B say a maximum of 75 watts for digital modes ... i.e., continuous duty modes. That pretty much says what the actual heat dissipation capability is. If he was trying to put 500 watts into his antenna in almost any mode, it is probably toast ... figuratively and literally. Dave AB7E On 1/14/2024 8:17 AM, Morgan Bailey wrote: The Cha250 b is NOT an antenna capable of greater than 100 watts for any length of time. It is a 5:1 unun hooked to a 23 foot aluminum radiator. It needs to be 30 feet in the air and if that happens it will function like a vertical OCFD. Still it is only good for 100 watts. When running a tuner with the KAT500 and KPA500 you are heating up the puny unun and the cores are totally being fried. Plus the reactance probably is generating high voltage on the short radiator causing arcs across any of the many connections inside the matching section. A guy fried a base section and I have it in the garage. That is your problem. I have owned 2 of the antennas and as such they work in a pinch and work well for fast POTA activation with 100 watts but other than that they are pretty much a megga compromise antenna. You would be way better off with a 998 mfg remote tuner and a 43 foot vertical over a radial field. Check out the Zero5 antennas for the cheapest durable 43foot vertical solution. 73, Morgan NJ8M BS + MS + $2.98 = COFFEE Real Life Experience = Priceless, says the man who set his back yard on fire with a breadboard tuner loading a 160 meter inverted L with 1000 watts. LOL __ 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
The Cha250 b is NOT an antenna capable of greater than 100 watts for any length of time. It is a 5:1 unun hooked to a 23 foot aluminum radiator. It needs to be 30 feet in the air and if that happens it will function like a vertical OCFD. Still it is only good for 100 watts. When running a tuner with the KAT500 and KPA500 you are heating up the puny unun and the cores are totally being fried. Plus the reactance probably is generating high voltage on the short radiator causing arcs across any of the many connections inside the matching section. A guy fried a base section and I have it in the garage. That is your problem. I have owned 2 of the antennas and as such they work in a pinch and work well for fast POTA activation with 100 watts but other than that they are pretty much a megga compromise antenna. You would be way better off with a 998 mfg remote tuner and a 43 foot vertical over a radial field. Check out the Zero5 antennas for the cheapest durable 43foot vertical solution. 73, Morgan NJ8M BS + MS + $2.98 = COFFEE Real Life Experience = Priceless, says the man who set his back yard on fire with a breadboard tuner loading a 160 meter inverted L with 1000 watts. LOL On Fri, Jan 12, 2024 at 4:28 PM Jim Brown wrote: > 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 mbaileyc...@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 1/13/2024 2:02 PM, email wrote: With the K4 power (drive) low enough, the amp can make 200W. Maybe not efficiently. I regularly reduce drive from K3 or K4 to big amp to run 100W in NAQP, and on 60M, and 200W on 30M. I do that because I run the K3 and K4 for two-radio contesting from a 100Ah LiFePO4 battery that is floated through a charge regulator. That allows the battery to keep up during a long contest, AND run the radios in the range of 13VDC, where the output stage runs cleaner. (yes, 200W is only 3db more than 100W) If FT8 RX level at -24, then 3db may be important ?? Depends on what you're trying to work, and conditions. I run legal limit with WSJT modes when going for DX on 160M (5,000 mile paths), and for weak signal propagation on 6M. 73, Jim K9YC steve WB3LGC On 1/12/24 7:52 PM, Ken WA8JXM wrote: Why do you have the amplifier running? 30m is as restricted power band. __ 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
The military isn't chasing DX or contesting ... They need enough radiation for adequate operation in their networks. In the example, a resistor in the folded dipole gives them that, they don't care about the 3dB, and a much easier radio system to set up. Little different for us "Amateurs." 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Ken WA8JXM wrote on 1/13/2024 9:16 PM: Unless its something like a log periodic, I think anything with those frequency/SWR specs can only do it with high resistive losses. It reminds me of the HF dipole B makes for the military: it is designed to appear to have a low SWR by having 3 db of resistive losses. The military considered that an acceptable design. Remember, antenna losses affect TX and RX, so that's 6 db system loss. Ken WA8JXM On 1/13/2024 2:37 PM, Walter Underwood wrote: The C HA-50HD is rated for 250 W SSB or 75 W for digital modes. It gets a flat SWR with resistive losses in the transformer. That is why the transformer has heat sink fins. A KPA500 is almost certainly overheating the transformer and causing failures. I would back off the power to match the ratings. For SSB with compression, I would run less than 250 W, maybe 150 W. It is possible that overheating has caused permanent damage to the transformer. One detailed set of tests showed at least 75% of transmitter power being turned into heat in the transformer. Here is what Comet says about that antenna. CHA-250HD (New version of the CHA-250B) The Comet CHA-250HD is the revised CHA-250B. The top section of aluminum has been replaced with a solid whip for greater flexibility and less strain on the lower sections in high winds. A uniquely designed broadband vertical requiring NO GROUND RADIALS. This is EXTREMELY easy to assemble, requires no tuning or adjustments and VSWR is under 1.6:1 continuously from 3.5MHz – 57MHz! It is not a 1/4 wave vertical, but an end-fed long wire type antenna with a matching transformer in a vertical position. Broadband: TX 3.5 – 57MHz RX 2.0 – 90MHz VSWR: 1.6:1 or less Max Power: 250W SSB 75W Digital modes/FT8, etc… CHA-250HD Transformer Section This is a the “magic” behind the CHA-250HD, the transformer matching section. The transformer on the original CHA-250 had smooth sides. The current version has a heat sink to dissipate heat created inside the transformer. Yes, some of the RF that enters the power feeding section is turned into heat rather than transmitted as RF, but that is one of the compromises needed to create a broad-band, low SWR, multi-band HF antenna with minimal visual impact. https://cometantenna.com/amateur-radio/base-antennas/multi-band-hfvhfuhf-2/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ 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 k6dg...@gmail.com -- This email has been checked for viruses by AVG antivirus software. www.avg.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
Unless its something like a log periodic, I think anything with those frequency/SWR specs can only do it with high resistive losses. It reminds me of the HF dipole B makes for the military: it is designed to appear to have a low SWR by having 3 db of resistive losses. The military considered that an acceptable design. Remember, antenna losses affect TX and RX, so that's 6 db system loss. Ken WA8JXM On 1/13/2024 2:37 PM, Walter Underwood wrote: The C HA-50HD is rated for 250 W SSB or 75 W for digital modes. It gets a flat SWR with resistive losses in the transformer. That is why the transformer has heat sink fins. A KPA500 is almost certainly overheating the transformer and causing failures. I would back off the power to match the ratings. For SSB with compression, I would run less than 250 W, maybe 150 W. It is possible that overheating has caused permanent damage to the transformer. One detailed set of tests showed at least 75% of transmitter power being turned into heat in the transformer. Here is what Comet says about that antenna. CHA-250HD (New version of the CHA-250B) The Comet CHA-250HD is the revised CHA-250B. The top section of aluminum has been replaced with a solid whip for greater flexibility and less strain on the lower sections in high winds. A uniquely designed broadband vertical requiring NO GROUND RADIALS. This is EXTREMELY easy to assemble, requires no tuning or adjustments and VSWR is under 1.6:1 continuously from 3.5MHz – 57MHz! It is not a 1/4 wave vertical, but an end-fed long wire type antenna with a matching transformer in a vertical position. Broadband: TX 3.5 – 57MHz RX 2.0 – 90MHz VSWR: 1.6:1 or less Max Power: 250W SSB 75W Digital modes/FT8, etc… CHA-250HD Transformer Section This is a the “magic” behind the CHA-250HD, the transformer matching section. The transformer on the original CHA-250 had smooth sides. The current version has a heat sink to dissipate heat created inside the transformer. Yes, some of the RF that enters the power feeding section is turned into heat rather than transmitted as RF, but that is one of the compromises needed to create a broad-band, low SWR, multi-band HF antenna with minimal visual impact. https://cometantenna.com/amateur-radio/base-antennas/multi-band-hfvhfuhf-2/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ 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
Check all of your connections such as PL-259 and SO-239. I once had the same problem with a dipole antenna and a loose shield wire would disconnect and put my SWR >9. You could also have a bad kink in your coax cable. Good Luck Sent with Proton Mail secure email. On Friday, January 12th, 2024 at 1:46 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 n6...@protonmail.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
With the K4 power (drive) low enough, the amp can make 200W. Maybe not efficiently. (yes, 200W is only 3db more than 100W) If FT8 RX level at -24, then 3db may be important ?? steve WB3LGC On 1/12/24 7:52 PM, Ken WA8JXM wrote: Why do you have the amplifier running? 30m is as restricted power band. __ 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 antenna is rated for 250 watts, which is most likely the cause of the problem. This is common, we upgrade from low power to high and don’t realize that we need to upgrade out antenna system as well. For use with the KPA500, you should replace it with an antenna with a higher rating. These are easy to fabricate - I am currently using a 110 foot long dipole with ladder line feed which is tunes quite nicely by the KAT500, and has no issues with either of my KPA500s. Just take a look at examples in the current ARRL Antenna book for better info. 73! Jack, W6FB > On Jan 12, 2024, at 11:28 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 > > > 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 <mailto: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 <http://www.qsl.net/> > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to jackbrin...@me.com <mailto:jackbrin...@me.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
The C HA-50HD is rated for 250 W SSB or 75 W for digital modes. It gets a flat SWR with resistive losses in the transformer. That is why the transformer has heat sink fins. A KPA500 is almost certainly overheating the transformer and causing failures. I would back off the power to match the ratings. For SSB with compression, I would run less than 250 W, maybe 150 W. It is possible that overheating has caused permanent damage to the transformer. One detailed set of tests showed at least 75% of transmitter power being turned into heat in the transformer. Here is what Comet says about that antenna. CHA-250HD (New version of the CHA-250B) The Comet CHA-250HD is the revised CHA-250B. The top section of aluminum has been replaced with a solid whip for greater flexibility and less strain on the lower sections in high winds. A uniquely designed broadband vertical requiring NO GROUND RADIALS. This is EXTREMELY easy to assemble, requires no tuning or adjustments and VSWR is under 1.6:1 continuously from 3.5MHz – 57MHz! It is not a 1/4 wave vertical, but an end-fed long wire type antenna with a matching transformer in a vertical position. Broadband: TX 3.5 – 57MHz RX 2.0 – 90MHz VSWR: 1.6:1 or less Max Power: 250W SSB 75W Digital modes/FT8, etc… CHA-250HD Transformer Section This is a the “magic” behind the CHA-250HD, the transformer matching section. The transformer on the original CHA-250 had smooth sides. The current version has a heat sink to dissipate heat created inside the transformer. Yes, some of the RF that enters the power feeding section is turned into heat rather than transmitted as RF, but that is one of the compromises needed to create a broad-band, low SWR, multi-band HF antenna with minimal visual impact. https://cometantenna.com/amateur-radio/base-antennas/multi-band-hfvhfuhf-2/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Jan 12, 2024, at 11:15 PM, Bruce Forsberg wrote: > > 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 wun...@wunderwood.org __ 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
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
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
