SWR question
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Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line.
On the KPA500 the SWR reads 1.3 with one or two SWR led's lit also one or two led's lit on the KAT500 but the SWR display on the P3 shows about 6. Any ideas why this is happening? Joe K2UF ______________________________________________________________ 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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Where is the TX sensor located? It should be between the KPA500 and the
KAT500. It sounds like you have it in-line after the KAT500. Mark, WB9CIF -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Joe K2UF Sent: Wednesday, September 14, 2016 6:49 PM To: [hidden email] Subject: [Elecraft] SWR question Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line. On the KPA500 the SWR reads 1.3 with one or two SWR led's lit also one or two led's lit on the KAT500 but the SWR display on the P3 shows about 6. Any ideas why this is happening? Joe K2UF ______________________________________________________________ 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 Joe K2UF
If your TX sensor is in line after the KAT500, you might be observing the
SWR of the antenna side of the ATU. The KPA500 and KAT500 LEDs show the SWR at the transmitter side of the ATU, rather than the antenna side. The KAT500 Utility will show the "bypass VSWR", which is the SWR observed by the ATU when it is in Bypass. 73 de Dick, K6KR -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Joe K2UF Sent: Wednesday, September 14, 2016 11:49 To: [hidden email] Subject: [Elecraft] SWR question Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line. On the KPA500 the SWR reads 1.3 with one or two SWR led's lit also one or two led's lit on the KAT500 but the SWR display on the P3 shows about 6. Any ideas why this is happening? Joe K2UF ______________________________________________________________ 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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> The KAT500 Utility will show the "bypass VSWR", which is the SWR observed
by the ATU when it is in Bypass. As will the SWR meter on the KPA500, right? Barthold -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Dick Dievendorff Sent: Wednesday, September 14, 2016 1:24 PM To: 'Joe K2UF'; [hidden email] Subject: Re: [Elecraft] SWR question If your TX sensor is in line after the KAT500, you might be observing the SWR of the antenna side of the ATU. The KPA500 and KAT500 LEDs show the SWR at the transmitter side of the ATU, rather than the antenna side. The KAT500 Utility will show the "bypass VSWR", which is the SWR observed by the ATU when it is in Bypass. 73 de Dick, K6KR -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Joe K2UF Sent: Wednesday, September 14, 2016 11:49 To: [hidden email] Subject: [Elecraft] SWR question Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line. On the KPA500 the SWR reads 1.3 with one or two SWR led's lit also one or two led's lit on the KAT500 but the SWR display on the P3 shows about 6. Any ideas why this is happening? Joe K2UF ______________________________________________________________ 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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Without seeing the entire diagram, SWR is not a consistent value throughout
the feedline. We actually proved this a one of my classes back in college. I can't remember how many jumper cables I made to up to this test at 100Mhz. All different wavelengths and random lengths as well. Let me borrow something Cecil KG7BK said in a previous forum a long time ago. *The SWR changes every inch up and down the transmission line because everyinch has a finite loss and because the SWR is never exactly 1/1 at theload. _For practical purposes_ if the transmission line is matchedto the load the SWR is close enough to 1/1. If the transmission line is not matched to the load, the SWR decreases in the direction toward the generator because of losses. Removing an inch of transmission linechanges the SWR... inserting an SWR meter changes the SWR... hopefullyby a neglible amount.* *SWR's of 1/1, infinite and zero impedences, exactly 50 ohm antennas andtransmission lines are human concepts that do not exist in reality.Sometimes they are good approximations to reality and sometimes they arenot.* Mike va3mw On Wed, Sep 14, 2016 at 3:55 PM, Barthold Lichtenbelt via Elecraft < [hidden email]> wrote: > > The KAT500 Utility will show the "bypass VSWR", which is the SWR observed > by the ATU when it is in Bypass. > > As will the SWR meter on the KPA500, right? > > Barthold > > -----Original Message----- > From: Elecraft [mailto:[hidden email]] On Behalf Of Dick > Dievendorff > Sent: Wednesday, September 14, 2016 1:24 PM > To: 'Joe K2UF'; [hidden email] > Subject: Re: [Elecraft] SWR question > > If your TX sensor is in line after the KAT500, you might be observing the > SWR of the antenna side of the ATU. The KPA500 and KAT500 LEDs show the SWR > at the transmitter side of the ATU, rather than the antenna side. > > The KAT500 Utility will show the "bypass VSWR", which is the SWR observed > by > the ATU when it is in Bypass. > > 73 de Dick, K6KR > > > > -----Original Message----- > From: Elecraft [mailto:[hidden email]] On Behalf Of Joe > K2UF > Sent: Wednesday, September 14, 2016 11:49 > To: [hidden email] > Subject: [Elecraft] SWR question > > Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line. > > On the KPA500 the SWR reads 1.3 with one or two SWR led's lit also one > or > two led's lit on the KAT500 but the SWR display on the P3 shows about 6. > > Any ideas why this is happening? > > Joe K2UF > ______________________________________________________________ > 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] > 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 Elecraft mailing list
Barthold,
No, the KPA500 will see the SWR at the *input* to the KAT500, and that is what it will display. The tuner will attempt to create a low SWR when it tunes. The output side of the KAT500 will be the SWR that is presented by the antenna feedline. The KAT500 Utility will show you that bypassed VSWR value even though the KAT500 is not bypassed. 73, Don W3FPR On 9/14/2016 3:55 PM, Barthold Lichtenbelt via Elecraft wrote: >> The KAT500 Utility will show the "bypass VSWR", which is the SWR observed > by the ATU when it is in Bypass. > > As will the SWR meter on the KPA500, right? > > ______________________________________________________________ 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 Don,
I meant if the KAT500 is in bypass mode, what will the SWR meter on the KPA500 show? Thanks, Barthold -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Wednesday, September 14, 2016 2:26 PM To: Barthold Lichtenbelt; 'Dick Dievendorff'; 'Joe K2UF'; [hidden email] Subject: Re: [Elecraft] SWR question Barthold, No, the KPA500 will see the SWR at the *input* to the KAT500, and that is what it will display. The tuner will attempt to create a low SWR when it tunes. The output side of the KAT500 will be the SWR that is presented by the antenna feedline. The KAT500 Utility will show you that bypassed VSWR value even though the KAT500 is not bypassed. 73, Don W3FPR On 9/14/2016 3:55 PM, Barthold Lichtenbelt via Elecraft wrote: >> The KAT500 Utility will show the "bypass VSWR", which is the SWR >> observed > by the ATU when it is in Bypass. > > As will the SWR meter on the KPA500, right? > > ______________________________________________________________ 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 Michael Walker
Actually, it doesn't. Slap a flat plate over the end of a zero length waveguide
and the SWR is infinite. Insert whatever you want in front of that and the SWR may measure something different, but it's still infinite:-) On 9/14/2016 1:11 PM, Michael Walker wrote: > inserting an SWR meter changes the SWR... > hopefullyby a neglible amount.* > ______________________________________________________________ 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 Elecraft mailing list
Barthold,
If the KAT500 is in bypass you should see a similar SWR indicated on both the KAT500 and the KPA500. They may not be exactly the same due to component tolerances in the wattmeters. I am not sure what your goal is in asking that question. If it is a quick check on your antenna system, then that indication should be adequate. If you really want to know the SWR on the feedline with greater accuracy, measure it with an antenna analyzer or put the Elecraft W2 Wattmeter in-line. 73, Don W3FPR On 9/14/2016 4:54 PM, Barthold Lichtenbelt wrote: > Hi Don, > > I meant if the KAT500 is in bypass mode, what will the SWR meter on the > KPA500 show? > > ______________________________________________________________ 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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Dear All,
I have a KPA500 and a KAT500 for sale. Both are in mint condition and very lightly used (I use an Alpha 9500 when I need an amp). KPA500 - $2,000 delivered and insured (cables included); KAT500 - $600.00 delivered and insured (cables included). Please email me directly at [hidden email]. 73, Bob/AA6VB ______________________________________________________________ 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
Hi Don,
Ok, this all came from Dick saying that you can see the "bypass SWR" that the KAT500 measures with the PC utility. But if you don't have that hooked up, a simple trick seemed to be to put the KAT500 in bypass mode, and see what the KPA500 tells you on its SWR led bar. That can give you an idea of the SWR past the KAT500 (thus the Antenna SWR). Of course, if the SWR is too far off the KPA500 will complain. If you have a P3 with TX sensor, and you want to know your antenna SWR, then putting the P3 TX sensor after the KAT500 seems like the way to go. That way you can quickly see how well your antenna is actually matched to the feedline, and you can use the KAT500 in tune mode (and not in bypass mode). Of course, a real antenna analyzer (I use a RigExpert 600) will be more accurate. Hope that explains it Don! Regards, Barthold -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Wednesday, September 14, 2016 3:32 PM To: Barthold Lichtenbelt; [hidden email] Subject: Re: [Elecraft] SWR question Barthold, If the KAT500 is in bypass you should see a similar SWR indicated on both the KAT500 and the KPA500. They may not be exactly the same due to component tolerances in the wattmeters. I am not sure what your goal is in asking that question. If it is a quick check on your antenna system, then that indication should be adequate. If you really want to know the SWR on the feedline with greater accuracy, measure it with an antenna analyzer or put the Elecraft W2 Wattmeter in-line. 73, Don W3FPR On 9/14/2016 4:54 PM, Barthold Lichtenbelt wrote: > Hi Don, > > I meant if the KAT500 is in bypass mode, what will the SWR meter on > the > KPA500 show? > > ______________________________________________________________ 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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Barthold,
Another way to accomplish that is to power off the KPA500 and bypass the KAT500. Then the K3 will display the SWR. There are several ways to "skin that cat". Actually, if you 'train' the KAT500 to your antennas and want to monitor the status of your antennas, put the KAT500 into manual mode after the training (you should do that anyway) - and then monitor the SWR seen by the LEDs on either the KPA500 or the KAT500. If there is a significant change, then take a look at your antenna(s) with your antenna analyzer. If no significant change in the SWR indication, then just keep operating because all is well. 73, Don W3FPR On 9/14/2016 11:01 PM, Barthold Lichtenbelt wrote: > Hi Don, > > Ok, this all came from Dick saying that you can see the "bypass SWR" that > the KAT500 measures with the PC utility. But if you don't have that hooked > up, a simple trick seemed to be to put the KAT500 in bypass mode, and see > what the KPA500 tells you on its SWR led bar. That can give you an idea of > the SWR past the KAT500 (thus the Antenna SWR). Of course, if the SWR is too > far off the KPA500 will complain. > > If you have a P3 with TX sensor, and you want to know your antenna SWR, then > putting the P3 TX sensor after the KAT500 seems like the way to go. That way > you can quickly see how well your antenna is actually matched to the > feedline, and you can use the KAT500 in tune mode (and not in bypass mode). > > Of course, a real antenna analyzer (I use a RigExpert 600) will be more > accurate. > > Hope that explains it Don! > ______________________________________________________________ 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 Don,
As you say "many ways to skin the cat" :-) Thanks for that last tip, hadn't thought of that and will work as well of course! Barthold -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Wednesday, September 14, 2016 9:35 PM To: Barthold Lichtenbelt; [hidden email] Subject: Re: [Elecraft] SWR question Barthold, Another way to accomplish that is to power off the KPA500 and bypass the KAT500. Then the K3 will display the SWR. There are several ways to "skin that cat". Actually, if you 'train' the KAT500 to your antennas and want to monitor the status of your antennas, put the KAT500 into manual mode after the training (you should do that anyway) - and then monitor the SWR seen by the LEDs on either the KPA500 or the KAT500. If there is a significant change, then take a look at your antenna(s) with your antenna analyzer. If no significant change in the SWR indication, then just keep operating because all is well. 73, Don W3FPR On 9/14/2016 11:01 PM, Barthold Lichtenbelt wrote: > Hi Don, > > Ok, this all came from Dick saying that you can see the "bypass SWR" > that the KAT500 measures with the PC utility. But if you don't have > that hooked up, a simple trick seemed to be to put the KAT500 in > bypass mode, and see what the KPA500 tells you on its SWR led bar. > That can give you an idea of the SWR past the KAT500 (thus the Antenna > SWR). Of course, if the SWR is too far off the KPA500 will complain. > > If you have a P3 with TX sensor, and you want to know your antenna > SWR, then putting the P3 TX sensor after the KAT500 seems like the way > to go. That way you can quickly see how well your antenna is actually > matched to the feedline, and you can use the KAT500 in tune mode (and not > > Of course, a real antenna analyzer (I use a RigExpert 600) will be > more accurate. > > Hope that explains it Don! > ______________________________________________________________ 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: KPA500/KAT500 For Sale
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In reply to this post by Elecraft mailing list
The KAT500 has been sold.
From: Chortek Bob via Elecraft <[hidden email]> To: "[hidden email]" <[hidden email]> Sent: Wednesday, September 14, 2016 3:59 PM Subject: [Elecraft] KPA500/KAT500 For Sale Dear All, I have a KPA500 and a KAT500 for sale. Both are in mint condition and very lightly used (I use an Alpha 9500 when I need an amp). KPA500 - $2,000 delivered and insured (cables included); KAT500 - $600.00 delivered and insured (cables included). Please email me directly at [hidden email]. 73, Bob/AA6VB ______________________________________________________________ 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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