Excessive SWR Faulting KPA500
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I discovered a problem this afternoon where the KPA500 is faulting on 20,
17 and 12 meters. Set up here is the K-line, K3/KAT500/KPA500. Everything had been working fine until this point. I get a hard fault (error code 9) on the three bands which means excessive SWR even though it has tuned fine before switching from standby. Antennas: 6BTV vertical and Inverted Vs for 17 and 12. The Vs are fed from a common point. The KPA500 works fine on 80 thru 10 on the 6BTV except 20 of course. I tried turning down the power when on 20 (via the K3 drive) but the SWR runs up and faults. I checked the Elecraft website but no schematics for the KPA500. My guess is the LPF units for the bands in question have gone TU. 73 de Ed ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Hi Ed,
What results do you observe when you connect the output of your KPA500 direct to a dummy load? 73 Frank W3LPL ----- Original Message ----- From: [hidden email] To: [hidden email] Sent: Saturday, April 18, 2020 12:18:55 AM Subject: [Elecraft] Excessive SWR Faulting KPA500 I discovered a problem this afternoon where the KPA500 is faulting on 20, 17 and 12 meters. Set up here is the K-line, K3/KAT500/KPA500. Everything had been working fine until this point. I get a hard fault (error code 9) on the three bands which means excessive SWR even though it has tuned fine before switching from standby. Antennas: 6BTV vertical and Inverted Vs for 17 and 12. The Vs are fed from a common point. The KPA500 works fine on 80 thru 10 on the 6BTV except 20 of course. I tried turning down the power when on 20 (via the K3 drive) but the SWR runs up and faults. I checked the Elecraft website but no schematics for the KPA500. My guess is the LPF units for the bands in question have gone TU. 73 de Ed ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Excessive SWR Faulting KPA500
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In reply to this post by k2te
Sounds as though the antenna has failed on those 3 bands. I doubt it
is the KPA500. Check the KPA500 feeding a known good 50 dummy load. If it is good there, then it is the antenna. If it shows the same results as with the antenna, then it is the amplifier. Also you can bypass the KPA500 to STBY mode and check the system by observing the SWR on the K3. 73 Bob, K4TAX On 4/17/2020 7:18 PM, [hidden email] wrote: > I discovered a problem this afternoon where the KPA500 is faulting on 20, > 17 and 12 meters. Set up here is the K-line, K3/KAT500/KPA500. > Everything had been working fine until this point. I get a hard fault > (error code 9) on the three bands which means excessive SWR even though > it has tuned fine before switching from standby. Antennas: 6BTV vertical > and Inverted Vs for 17 and 12. The Vs are fed from a common point. The > KPA500 works fine on 80 thru 10 on the 6BTV except 20 of course. I tried > turning down the power when on 20 (via the K3 drive) but the SWR runs up > and faults. > > I checked the Elecraft website but no schematics for the KPA500. My > guess is the LPF units for the bands in question have gone TU. > > 73 de Ed > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > -- This email has been checked for viruses by AVG. https://www.avg.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k2te
Bob,
You mentioned: "Also you can bypass the KPA500 to STBY mode and check the system by observing the SWR on the K3." I think you meant the KAT500 instead of the K3. The K3 has to be bypassed to work with the tuner. Anyway, I have made some progress. I tried running through my dummy load and I got the run-up condition to fault on 17 and 20. I had to run reduced power since the load is only rated for 300W. The odd thing is that I had to use the tuner to make things happy with the load. Thanks to AI4VZ, I have the schematics for the KPA500 and the LPF details. The schematics are from 2011 or so and my gear is from 2017 but I doubt the design changed significantly. After testing with the dummy load, I re-connected to my patch panel only to find that all the settings in the KAT500 were gone. I had to retune from 80 through 10; what a PITA! However, my efforts were rewarded with the amp working fine on CW everywhere except 12 meters. I may have an intermittent on 12 since the best I can do is 2.9:1 SWR after the tuner shuts up. Since both the 12 and 17 meter Vs are off the same feed point, the 17 may be guilty as well; it settles around 1.9:1. As for the amp faulting, I may have an RFI issue. The 6BTV is only six feet from the shack. Another possibility: the fault surfaced when running the amp on FT8. The long duty cycle plus RFI may have done me in. Tnx for your help. 73 de Ed ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Hi Ed,
At a distance of only six feet to your antenna, perhaps your amplifier is trying to warn you that you may also have a human RF safety issue. 73 Frank W3LPL ----- Original Message ----- From: [hidden email] To: [hidden email] Cc: [hidden email] Sent: Saturday, April 18, 2020 7:53:06 PM Subject: Re: [Elecraft] Excessive SWR Faulting KPA500 Bob, You mentioned: "Also you can bypass the KPA500 to STBY mode and check the system by observing the SWR on the K3." I think you meant the KAT500 instead of the K3. The K3 has to be bypassed to work with the tuner. Anyway, I have made some progress. I tried running through my dummy load and I got the run-up condition to fault on 17 and 20. I had to run reduced power since the load is only rated for 300W. The odd thing is that I had to use the tuner to make things happy with the load. Thanks to AI4VZ, I have the schematics for the KPA500 and the LPF details. The schematics are from 2011 or so and my gear is from 2017 but I doubt the design changed significantly. After testing with the dummy load, I re-connected to my patch panel only to find that all the settings in the KAT500 were gone. I had to retune from 80 through 10; what a PITA! However, my efforts were rewarded with the amp working fine on CW everywhere except 12 meters. I may have an intermittent on 12 since the best I can do is 2.9:1 SWR after the tuner shuts up. Since both the 12 and 17 meter Vs are off the same feed point, the 17 may be guilty as well; it settles around 1.9:1. As for the amp faulting, I may have an RFI issue. The 6BTV is only six feet from the shack. Another possibility: the fault surfaced when running the amp on FT8. The long duty cycle plus RFI may have done me in. Tnx for your help. 73 de Ed ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k2te
"At a distance of only six feet to your antenna, perhaps your amplifier is trying to warn you that you may also have a human RF safety issue. "
Well, do you feel warm.... We do what we must to get a signal out. My 40 m dipole is in the attic of a single story house under an asphalt and fibreglass radome. Yes I have RF in the "shack" and every other room in the house. My choice how high I turn the wick though and that choice is less than 500 W. My "controller" prevents my getting excited and turning the wick up all the way. Antenna is well matched though and KPA500 is happy. The only problems I've had with an unhappy KPA500 were on 20 m. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Hi Andy,
A very close 40 meter antenna is much safer than a close 12 or 10 meter antenna See FCC Amateur Radio Regulations: Part 97.13 Restrictions on station location. (c) Before causing or allowing an amateur station to transmit from any place where the operation of the station could cause human exposure to RF electromagnetic field levels in excess of those allowed under §1.1310 of this chapter, the licensee is required to take certain actions. (1) The licensee must perform the routine RF environmental evaluation prescribed by §1.1307(b) of this chapter, if the power of the licensee's station exceeds the limits given in the following table: Evaluation required if power in (watts) exceeds: 160m 500 watts 80 m 500 watts 75 m 500 watts 40 m 500 watts 30 m 425 watts 20 m 225 watts 17 m 125 watts 15 m 100 watts 12 m 75 watts 10 m 50 watts (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could exceed the limits contained in §1.1310 of this chapter in accessible areas, the licensee must take action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating compliance with these limits can be found in the FCC's OET Bulletin Number 65, “Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields.” 73 Frank W3LPL ----- Original Message ----- From: "Andy Durbin" <[hidden email]> To: [hidden email] Sent: Sunday, April 19, 2020 12:07:13 AM Subject: [Elecraft] Excessive SWR Faulting KPA500 "At a distance of only six feet to your antenna, perhaps your amplifier is trying to warn you that you may also have a human RF safety issue. " Well, do you feel warm.... We do what we must to get a signal out. My 40 m dipole is in the attic of a single story house under an asphalt and fibreglass radome. Yes I have RF in the "shack" and every other room in the house. My choice how high I turn the wick though and that choice is less than 500 W. My "controller" prevents my getting excited and turning the wick up all the way. Antenna is well matched though and KPA500 is happy. The only problems I've had with an unhappy KPA500 were on 20 m. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Excessive SWR Faulting KPA500
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"A very close 40 meter antenna is much safer than a close 12 or 10 meter antenna "
I used to teach the RF safety class for our club's extra and general course students. Most people in the Extra course were already General and almost none of them had ever conducted an RF safety evaluation. I don't think any of the Extra student even knew what an RF safety evaluation was. A concern for my station is that my roof mounted 2 ele SteppIR can be pointed directly into my neighbor's 2 story house. Good thing there is little DX to chase directly north of my QTH. Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by donovanf
Hi guys,
Here in Canada we have something called Safety Code 6, which states that a field strength level on any HF frequency over 3.16V/m is unsafe in an uncontrolled space. On a small city lot, close to neighbors, the power you're mentioning will definitely exceed 3.16V/m. What levels to do you have to comply with in the US? Bert VE3NR On 4/18/2020 8:33 PM, [hidden email] wrote: > Hi Andy, > > > A very close 40 meter antenna is much safer than a close 12 or 10 meter antenna > > > See FCC Amateur Radio Regulations: Part 97.13 Restrictions on station location. > > > (c) Before causing or allowing an amateur station to transmit from any > place where the operation of the station could cause human exposure to > RF electromagnetic field levels in excess of those allowed under §1.1310 > of this chapter, the licensee is required to take certain actions. > > > (1) The licensee must perform the routine RF environmental evaluation > prescribed by §1.1307(b) of this chapter, if the power of the licensee's > station exceeds the limits given in the following table: > Evaluation required if power in (watts) exceeds: > 160m 500 watts > 80 m 500 watts > 75 m 500 watts > 40 m 500 watts > 30 m 425 watts > 20 m 225 watts > 17 m 125 watts > 15 m 100 watts > 12 m 75 watts > 10 m 50 watts > > > (2) If the routine environmental evaluation indicates that the RF electromagnetic > fields could exceed the limits contained in §1.1310 of this chapter in accessible > areas, the licensee must take action to prevent human exposure to such RF > electromagnetic fields. Further information on evaluating compliance with these > limits can be found in the FCC's OET Bulletin Number 65, “Evaluating > Compliance with FCC Guidelines for Human Exposure to Radiofrequency > Electromagnetic Fields.” > > > 73 > Frank > W3LPL > > ----- Original Message ----- > > From: "Andy Durbin" <[hidden email]> > To: [hidden email] > Sent: Sunday, April 19, 2020 12:07:13 AM > Subject: [Elecraft] Excessive SWR Faulting KPA500 > > "At a distance of only six feet to your antenna, perhaps your amplifier is trying to warn you that you may also have a human RF safety issue. " > > Well, do you feel warm.... > > We do what we must to get a signal out. My 40 m dipole is in the attic of a single story house under an asphalt and fibreglass radome. Yes I have RF in the "shack" and every other room in the house. My choice how high I turn the wick though and that choice is less than 500 W. My "controller" prevents my getting excited and turning the wick up all the way. > > Antenna is well matched though and KPA500 is happy. The only problems I've had with an unhappy KPA500 were on 20 m. > > 73, > Andy, k3wyc > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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