KPA1500 SWR meter
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I have noticed that after my KPA1500 gets above 50C the SWR indicator light starts to show intermittent high SWR. My KPA500 did not do that. I'm using resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor does the SWR indicator on the K3S. It seems the SWR indicator lights are acting independent of the meter on the KPA1500 screen. RF? I have not had any faults or shut downs as a result of the indicated high SWR. The amp operates wonderfully, but the indicator lights are a bit bothersome. Anyone have similar issues?
73, Mike AD5A ______________________________________________________________ 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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I have experienced strange SWR indications (high SWR) when the SWR shows 1:1 on the K3S. Note: no ATU in the K3S.
> On Apr 29, 2018, at 10:13 AM, Mike Crownover <[hidden email]> wrote: > > I have noticed that after my KPA1500 gets above 50C the SWR indicator light starts to show intermittent high SWR. My KPA500 did not do that. I'm using resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor does the SWR indicator on the K3S. It seems the SWR indicator lights are acting independent of the meter on the KPA1500 screen. RF? I have not had any faults or shut downs as a result of the indicated high SWR. The amp operates wonderfully, but the indicator lights are a bit bothersome. Anyone have similar issues? > 73, > Mike AD5A > ______________________________________________________________ > 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] Carl Yaffey K8NU Recording studio. [hidden email] 614 268 6353, Columbus OH http://www.carl-yaffey.com http://www.grassahol.com http://www.bluesswing.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 Mike Crownover
Mike,
May I suggest you inspect all the connections in your antenna system. There are connections that may be just fine at 500 watts, but will either break down or arc over at 1500 watts. What happens if you drive the KPA1500 only to 500 watts? If it behaves the same as it does at 1500 watts, then you may have a problem with the KPA1500, but if things behave normally at 500 watts, then look at your antenna system. 73, Don W3FPR On 4/29/2018 10:13 AM, Mike Crownover wrote: > I have noticed that after my KPA1500 gets above 50C the SWR indicator light starts to show intermittent high SWR. My KPA500 did not do that. I'm using resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor does the SWR indicator on the K3S. It seems the SWR indicator lights are acting independent of the meter on the KPA1500 screen. RF? I have not had any faults or shut downs as a result of the indicated high SWR. The amp operates wonderfully, but the indicator lights are a bit bothersome. Anyone have similar issues? ______________________________________________________________ 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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Mike,
Have you looked at the SWR report shown in KPA1500 Utility? Try that and see whether it shows the same as the display. There are 2 pieces to the SWR - there is the sensor part and then there is the display part. There is a possibility that the sensor is doing OK, but the display end of things may be what is causing the problem. KPA1500 Utility uses a different path (but the same sensor) for its display of SWR than the front panel display. In either case, it does seem (by my first guess) that there is a solder or cable connection in the KPA1500 that is heat sensitive. How high does the SWR go? If it stays below 1.5, it will cause no problem despite your concern for that behavior. Unless I am mistaken, the SWR indication on the K3 shows only the SWR of what is connected to the K3, which is the amplifier input 73, Don W3FPR On 4/29/2018 2:25 PM, Mike Crownover wrote: > Don, > > Thanks for the comment. I’ve done that test and at low temps,~35c, no > difference at 1500 or 500. I haven’t done it at high temps yet, but I > would think if it were arcing, the temp of the amp wouldn’t matter, > although I’m certainly no expert on these matters. Additionally, I > would expect the SWR indicator on the screen to show the fluctuation > as well. It never moves from 1.1:1. > > Mike AD5A > ______________________________________________________________ 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 Mike Crownover
Mike,
You mention this occurs when interior temp reaches 50c (122F). Just a guess that a device in the SWR ckt or indicator driver is changing bias with temp and giving a false indication. This is really a question for Elecraft Tech Dept. I I am correct in my supposition they, already know about it. Might be a need for better air circulation for the amp, if so. 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: [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 Don Wilhelm
Don,
I downloaded the utility and SWR displayed stayed the same, 1.1:1 while the display on the KPA1500 peaked at 2 to 1, one red light. This occurs around 60C. No problem until then. 73, Mike AD5A -----Original Message----- From: Don Wilhelm <[hidden email]> Sent: Sunday, April 29, 2018 2:28 PM To: Mike Crownover <[hidden email]>; Mike Crownover <[hidden email]>; [hidden email] Subject: Re: [Elecraft] KPA1500 SWR meter Mike, Have you looked at the SWR report shown in KPA1500 Utility? Try that and see whether it shows the same as the display. There are 2 pieces to the SWR - there is the sensor part and then there is the display part. There is a possibility that the sensor is doing OK, but the display end of things may be what is causing the problem. KPA1500 Utility uses a different path (but the same sensor) for its display of SWR than the front panel display. In either case, it does seem (by my first guess) that there is a solder or cable connection in the KPA1500 that is heat sensitive. How high does the SWR go? If it stays below 1.5, it will cause no problem despite your concern for that behavior. Unless I am mistaken, the SWR indication on the K3 shows only the SWR of what is connected to the K3, which is the amplifier input 73, Don W3FPR On 4/29/2018 2:25 PM, Mike Crownover wrote: > Don, > > Thanks for the comment. Ive done that test and at low temps,~35c, no > difference at 1500 or 500. I havent done it at high temps yet, but I > would think if it were arcing, the temp of the amp wouldnt matter, > although Im certainly no expert on these matters. Additionally, I > would expect the SWR indicator on the screen to show the fluctuation > as well. It never moves from 1.1:1. > > Mike AD5A > ______________________________________________________________ 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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Mike,
I have never had my hands on the innards of the KPA1500, so I can't offer much except for you to email [hidden email]. 73, Don W3FPR On 4/30/2018 1:45 PM, [hidden email] wrote: > Don, > > I downloaded the utility and SWR displayed stayed the same, 1.1:1 while the > display on the KPA1500 peaked at 2 to 1, one red light. This occurs around > 60C. No problem until then. > ______________________________________________________________ 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 Mike Crownover
Mike I had the very same thing happen last night while operating the 7QP
contest..... which is the first contest I have operated with the KPA1500 .... the heatsink temperature was down in the mid 40s C at the time .... and in my case it occurred on 160 meters only .... SWR as per other meters as well as the digital readout on the 1500 were reading 1.2:1 ... and did not change even when the LED flashing occurred ..... but I was getting intermittent flashing of all LEDs on the amp's SWR meter .... During the contest I was continuously running on CW with hourly QSO rates running between the 70s and 110s .... I opted to manually switch on the fan to keep the temperature below 60 degs C ..... level 2 seemed to keep it there most of the time .... but I did move up to level 3 a few times (and BTW, at that speed the KPA1500 is clearly the noisiest amp I have ever owned .... but, arguably, it may very well be the "coolest" also ..... headphones were absolutely necessary with that noisy fan ..... clearly much noisier than the Alpha 9500 sitting right next door ... which I also used during the same contest... So Mike, you're not the only one experiencing this phenomenon.... whatever it is.. Don, N5LZ (KPA1500 #45) -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Mike Crownover Sent: Sunday, April 29, 2018 8:13 AM To: [hidden email] Subject: [Elecraft] KPA1500 SWR meter I have noticed that after my KPA1500 gets above 50C the SWR indicator light starts to show intermittent high SWR. My KPA500 did not do that. I'm using resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor does the SWR indicator on the K3S. It seems the SWR indicator lights are acting independent of the meter on the KPA1500 screen. RF? I have not had any faults or shut downs as a result of the indicated high SWR. The amp operates wonderfully, but the indicator lights are a bit bothersome. Anyone have similar issues? 73, Mike AD5A ______________________________________________________________ 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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I have the same problem with S/N 64. I thought it might be a cable but the
problem occurs on all bands, both antenna outputs and into a dummy load. I'm only about 90% sure that it is related to temperature - I was too busy working the contest to do much more troubleshooting. And I agree with the fan noise comments - the pitch of the noise comes right through my Bose noise canceling headphones. 73, Bud N7CW On Sun, May 6, 2018 at 3:43 PM Don Butler <[hidden email]> wrote: > Mike I had the very same thing happen last night while operating the 7QP > contest..... which is the first contest I have operated with the KPA1500 > .... the heatsink temperature was down in the mid 40s C at the time .... > and > in my case it occurred on 160 meters only .... SWR as per other meters as > well as the digital readout on the 1500 were reading 1.2:1 ... and did not > change even when the LED flashing occurred ..... but I was getting > intermittent flashing of all LEDs on the amp's SWR meter .... > > During the contest I was continuously running on CW with hourly QSO rates > running between the 70s and 110s .... I opted to manually switch on the fan > to keep the temperature below 60 degs C ..... level 2 seemed to keep it > there most of the time .... but I did move up to level 3 a few times (and > BTW, at that speed the KPA1500 is clearly the noisiest amp I have ever > owned > .... but, arguably, it may very well be the "coolest" also ..... headphones > were absolutely necessary with that noisy fan ..... clearly much noisier > than the Alpha 9500 sitting right next door ... which I also used during > the > same contest... > > So Mike, you're not the only one experiencing this phenomenon.... whatever > it is.. > > Don, N5LZ (KPA1500 #45) > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Mike Crownover > Sent: Sunday, April 29, 2018 8:13 AM > To: [hidden email] > Subject: [Elecraft] KPA1500 SWR meter > > I have noticed that after my KPA1500 gets above 50C the SWR indicator light > starts to show intermittent high SWR. My KPA500 did not do that. I'm using > resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor > does the SWR indicator on the K3S. It seems the SWR indicator lights are > acting independent of the meter on the KPA1500 screen. RF? I have not had > any faults or shut downs as a result of the indicated high SWR. The amp > operates wonderfully, but the indicator lights are a bit bothersome. Anyone > have similar issues? > 73, > Mike AD5A > ______________________________________________________________ > 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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