K3 Strange Problem
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Guy, Don
I don't get the emails just the digest show your emails to me. I agree the antenna should be the first place and in fact I did look at it hanging in the air but I have not lowered it to give it a closer inspection. Unfortunately my antenna analyzer is one MFJ's first and only gives SWR and Resistance. It did not really show anything helpful. Since it is an 88' long dipole it isn't resonant any any of the bands. Here is what is strange about this. I have only had the K3 a few weeks. I did not have a problem tuning on 30m. The first time the problem occurred was when I went SPLIT then turned on the SUB rx. Immediately it gave the HIGH SWR warning. Then I tried tune and got the strange tuning behavior. So I began to trouble shoot the problem. I tried different combinations of settings, etc. The antenna comes in to an antenna switch with one position on the K3 and the other on the K2. I wanted to eliminate the switch and connect directly to the coax coming from the balun. To get to where I could make that connection I had to completely disconnect everything from the back of the K3 and move close enough to reach that coax, thus bypassing the switch. So I did that and when I tried a tune I got the same result, it tuned to the same spot and stopped. No difference. Then I redid all the cables to the rear of the K3. And guess what. This time when I hit tune it went right to 1:1.2 without hardly any relay action. So did some tests, retuning and so forth. It continued to work okay. I even had a qso with a good rst. That was last Saturday. On Sunday afternoon, I came in and tuning on 30m found a dx station working pileup. That is when I went A>B, SPLIT and then turned on SUB. As soon as I hit the paddle and it went to transmit, the HIGH SWR message appeared and when I tried ANT TUNE it tuned just like it had before. SWR shows max and RF out shows min while relays are working, then it SWR drops to 1:1.8 to 2 and power out shows 100w (what it is set for). I don't know why the problem went away when it did, I have not been able to duplicate again. d I'll take down the ant and inspect it.But it works fine on all the other bands. Tunes with no problems all other bands. The KAT100 tunes but the KAT3 doesn't? Thanks, guys, for your suggestions. Joe k4nvj ______________________________________________________________ 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 |
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Joe,
In addition to the antenna check out, try replacing the patch cables from the K3 to the switch as well, you may have an intermittent there or poor bonding to the shield (a common problem, making effective coax connector bonds is a learned art). I think you said you were using a balun to the ladder line. That run of coax to the switch (and K3) should be as short as possible too (some say under ten feet total between tuner and balun, some say shorter). It's all part of the antenna load equation for the tuner and you may have some reaction there. Bypassing the switch (use a barrel connector if you must) eliminates that as a problem source. It could have an open, a short or intermittent (or poor connector). Is the ladder line a reactive length on any band? When you drop the antenna, give the ladder line a look see too. Did a raven do something nasty to the line? What happens when you tune into a dummy load? Is it consistent? Pick one end and work toward the other end, eliminating the possibilities in a logical manner. You'll get there and then can let us know what you find. With me, it's often a DOH! moment. ;-) Rick WA6NHC -----Original Message----- From: Joe Ford I did not have a problem tuning on 30m. The first time the problem occurred was when I went <SNIP> I wanted to eliminate the switch and connect directly to the coax coming from the balun. To get to where I could make that connection I had to <SNIP> Then I redid all the cables to the rear of the K3. And guess what. This time when I hit tune it went right to 1:1.2 without hardly any relay action. So did some tests, retuning and so forth. It continued to work okay. I even had a qso with a good rst. ______________________________________________________________ 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 |
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In reply to this post by Joe Ford-2
Joe,
You results seem to be erratic. Loose PL-259s can cause symptoms like that. Finger tight for PL-259s is not good enough, the connectors must be seated in the notches, and after finger-tightening, must be torqued a bit more with pliers to obtain a secure connection. The connection to the coax shell depends on having them tight. Also check to be certain all PL-259s have good soldering to the braid. That is the cause of many problems that work well one time, but fail the next time it is tried. A bad connection to the shield can (and will) produce a HIGH SWR indication. I am not saying you have exactly the problems I have indicated, but something similar may be present. 73, Don W3FPR On 11/1/2011 9:24 PM, Joe Ford wrote: > Guy, Don > > I don't get the emails just the digest show your emails to me. > > I agree the antenna should be the first place and in fact I did look > at it hanging in the air but I have not lowered it to give it a closer > inspection. Unfortunately my antenna analyzer is one MFJ's first and > only gives SWR and Resistance. It did not really show anything > helpful. Since it is an 88' long dipole it isn't resonant any any of > the bands. > > Here is what is strange about this. I have only had the K3 a few > weeks. I did not have a problem tuning on 30m. The first time the > problem occurred was when I went SPLIT then turned on the SUB rx. > Immediately it gave the HIGH SWR warning. Then I tried tune and got > the strange tuning behavior. So I began to trouble shoot the problem. > I tried different combinations of settings, etc. The antenna comes in > to an antenna switch with one position on the K3 and the other on the > K2. I wanted to eliminate the switch and connect directly to the coax > coming from the balun. To get to where I could make that connection I > had to completely disconnect everything from the back of the K3 and > move close enough to reach that coax, thus bypassing the switch. So I > did that and when I tried a tune I got the same result, it tuned to > the same spot and stopped. No difference. Then I redid all the cables > to the rear of the K3. And guess what. This time when I hit tune it > went right to 1:1.2 without hardly any relay action. So did some > tests, retuning and so forth. It continued to work okay. I even had a > qso with a good rst. > > That was last Saturday. On Sunday afternoon, I came in and tuning on > 30m found a dx station working pileup. That is when I went A>B, SPLIT > and then turned on SUB. As soon as I hit the paddle and it went to > transmit, the HIGH SWR message appeared and when I tried ANT TUNE it > tuned just like it had before. SWR shows max and RF out shows min > while relays are working, then it SWR drops to 1:1.8 to 2 and power > out shows 100w (what it is set for). I don't know why the problem > went away when it did, I have not been able to duplicate again. d > > I'll take down the ant and inspect it.But it works fine on all the > other bands. Tunes with no problems all other bands. The KAT100 tunes > but the KAT3 doesn't? > > Thanks, guys, for your suggestions. > > Joe > k4nvj 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 |
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Good catch Don. And it should be noted that not all PL-259 mate properly if
the outer shaft of the SO-239 (or barrel connector) is too short. It should be seated, tight and with no movement in any direction. Though I don't use pliers; I just crank on it and check them periodically. Rick WA6NHC -----Original Message----- From: Don Wilhelm Loose PL-259s can cause symptoms like that. ______________________________________________________________ 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 |
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Don't forget the 'quality of PL259 plugs' issue that's has been mentioned on here before. A while ago I nearly pulled my amp apart to check the input relay to see if that was the cause of my intermittent 'Hi SWR' and no rx signal problem. Problem was an intermittent mating of the PL259 centre pin in the socket barrel; either the pin was slightly undersize or the barrel had previously been expanded by a PL259 with too much solder on the pin.
73, Stewart, GW0ETF
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In reply to this post by Joe Ford-2
On Tue, Nov 1, 2011 at 9:24 PM, Joe Ford <[hidden email]> wrote:
... I'll take down the ant and inspect it.But it works fine on all the other > bands. Tunes with no problems all other bands. The KAT100 tunes but the KAT3 > doesn't? Tuning all bands using a single antenna is always dicey somewhere.Success is NOT guaranteed, but fortunate. You are often operating at the fringe of a tuner's range on one band or another. The KAT 100 and KAT3 are not the same tuners, have different coils, different tradeoffs, and different firmware to drive it. Though the ranges are approximately the same, give the two units an impedance at the far fringe, and one or the other may not be able tune it properly. Change any of the coax lengths after the tuner, INCLUDING THOSE INSIDE THE K3, by switching, exchange, or whatever, and what just barely got tuned the last time by the same tuner may not now tune. Though this may not be your problem at all, a friend of mine was having troubles of this mysterious sort. Eventually he discovered that he had not soldered either the braid OR the center conductor on a PL259. It worked for YEARS before it finally started getting intermittent. Another ham had a balun that was gradually going bad and overheating, apparently shorting some turns and causing mysterious changes in SWR. He discovered that because during a QRO contest it caught fire and completely shorted out. Actually his wife discovered it looking out the window at the tower out in the field, and came and told him his tower was on fire. The way to validate and check out one of these compromise antennas, is to run it when it is brand new and working spiffy. SWEEP the MFJ CONTINUOUSLY from the bottom of the lowest band to the top of the highest band. Note the actual resonances you find along the way. Write down those frequencies, the R at those resonant frequencies, and the 2:1 SWR points above and below all of those resonances. Entirely possible that all of the resonances are outside the ham bands. Keep these figures as a reference. When you have trouble, repeat the measurements. IF there is trouble in the antenna, those readings will change. If the coax gets waterlogged, the 2:1 SWR points will broaden out significantly and the R values at resonance will likely change. If something gets broken the resonances will all move on you. If you have an AIM 4170 as your analyzer, just sweep it from 0.5 to 30 MHz and save the file. You can then import it and have an onscreen compare between the old and new readings. 73, Guy. ______________________________________________________________ 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 |
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Guy,
Thanks for the tips. My coax jumpers are some I bought from a company I don't remember exactly which one. It was one that I saw recommended somewhere. Unfortunately the PL259s are crimped on but they seem to work okay. Just to be sure, when I was troubleshooting the problem I replaced the jumper with no change. I can't remember if I traded with the K2. I might have. I need to change the coax anyway because I need them to be a little longer. If I can find someone who sells good quality with soldered PL259s I'll probably order them, otherwise I'll just make my on. I lowered the dipole, looked it over but didn't see anything except the ends a rusting a little where they are tied to the insulators. Unfortunately it doesn't hang free and clear. I have lots of trees. I tried to reroute it where it would be more in the clear. Then I put it back up and it performs the same. I guess the next step is to replace it with the other dipole that tested okay. When I did the test I just hung the dipole between 2 trees. I did not hang it where the problem dipole is so it was not a 100% valid test. I'll try switching the 2 and see what happens. At least the test confirmed the switch and balun are okay. Thanks for the suggestion about recording the swr across the antenna bandwidth when it is new. I can plot a little graph and save it for future use. Even for my beam which is not new it will be a good thing to have. Joe k4nvj ________________________________ From: Guy Olinger K2AV <[hidden email]> To: Joe Ford <[hidden email]> Cc: Elecraft <[hidden email]>; "[hidden email]" <[hidden email]> Sent: Wednesday, November 2, 2011 3:49 PM Subject: Re: K3 Strange Problem On Tue, Nov 1, 2011 at 9:24 PM, Joe Ford <[hidden email]> wrote: ... I'll take down the ant and inspect it.But it works fine on all the other > bands. Tunes with no problems all other bands. The KAT100 tunes but the KAT3 > doesn't? Tuning all bands using a single antenna is always dicey somewhere.Success is NOT guaranteed, but fortunate. You are often operating at the fringe of a tuner's range on one band or another. The KAT 100 and KAT3 are not the same tuners, have different coils, different tradeoffs, and different firmware to drive it. Though the ranges are approximately the same, give the two units an impedance at the far fringe, and one or the other may not be able tune it properly. Change any of the coax lengths after the tuner, INCLUDING THOSE INSIDE THE K3, by switching, exchange, or whatever, and what just barely got tuned the last time by the same tuner may not now tune. Though this may not be your problem at all, a friend of mine was having troubles of this mysterious sort. Eventually he discovered that he had not soldered either the braid OR the center conductor on a PL259. It worked for YEARS before it finally started getting intermittent. Another ham had a balun that was gradually going bad and overheating, apparently shorting some turns and causing mysterious changes in SWR. He discovered that because during a QRO contest it caught fire and completely shorted out. Actually his wife discovered it looking out the window at the tower out in the field, and came and told him his tower was on fire. The way to validate and check out one of these compromise antennas, is to run it when it is brand new and working spiffy. SWEEP the MFJ CONTINUOUSLY from the bottom of the lowest band to the top of the highest band. Note the actual resonances you find along the way. Write down those frequencies, the R at those resonant frequencies, and the 2:1 SWR points above and below all of those resonances. Entirely possible that all of the resonances are outside the ham bands. Keep these figures as a reference. When you have trouble, repeat the measurements. IF there is trouble in the antenna, those readings will change. If the coax gets waterlogged, the 2:1 SWR points will broaden out significantly and the R values at resonance will likely change. If something gets broken the resonances will all move on you. If you have an AIM 4170 as your analyzer, just sweep it from 0.5 to 30 MHz and save the file. You can then import it and have an onscreen compare between the old and new readings. 73, Guy. ______________________________________________________________ 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 |
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There is nothing wrong with crimped connectors if done properly. Is
this an antenna that was working fine and then stopped on one band with absolutely no changed in the shack or coax etc? What band is out of whack...I apologize for missing most of this thread. Mike W0MU J6M CQ WW DX CW Contest 2011 J6/W0MU November 21 - December 1 2011 W0MU-1 CC Cluster w0mu.net On 11/2/2011 6:55 PM, Joe Ford wrote: > Guy, > > Thanks for the tips. My coax jumpers are some I bought from a company I don't remember exactly which one. It was one that I saw recommended somewhere. Unfortunately the PL259s are crimped on but they seem to work okay. Just to be sure, when I was troubleshooting the problem I replaced the jumper with no change. I can't remember if I traded with the K2. I might have. I need to change the coax anyway because I need them to be a little longer. If I can find someone who sells good quality with soldered PL259s I'll probably order them, otherwise I'll just make my on. > > I lowered the dipole, looked it over but didn't see anything except the ends a rusting a little where they are tied to the insulators. Unfortunately it doesn't hang free and clear. I have lots of trees. I tried to reroute it where it would be more in the clear. Then I put it back up and it performs the same. I guess the next step is to replace it with the other dipole that tested okay. When I did the test I just hung the dipole between 2 trees. I did not hang it where the problem dipole is so it was not a 100% valid test. I'll try switching the 2 and see what happens. At least the test confirmed the switch and balun are okay. > > > Thanks for the suggestion about recording the swr across the antenna bandwidth when it is new. I can plot a little graph and save it for future use. Even for my beam which is not new it will be a good thing to have. > > > Joe > k4nvj > > > > ________________________________ > From: Guy Olinger K2AV<[hidden email]> > To: Joe Ford<[hidden email]> > Cc: Elecraft<[hidden email]>; "[hidden email]"<[hidden email]> > Sent: Wednesday, November 2, 2011 3:49 PM > Subject: Re: K3 Strange Problem > > On Tue, Nov 1, 2011 at 9:24 PM, Joe Ford<[hidden email]> wrote: > > ... I'll take down the ant and inspect it.But it works fine on all the other >> bands. Tunes with no problems all other bands. The KAT100 tunes but the KAT3 >> doesn't? > Tuning all bands using a single antenna is always dicey > somewhere.Success is NOT guaranteed, but fortunate. You are often > operating at the fringe of a tuner's range on one band or another. > The KAT 100 and KAT3 are not the same tuners, have different coils, > different tradeoffs, and different firmware to drive it. Though the > ranges are approximately the same, give the two units an impedance at > the far fringe, and one or the other may not be able tune it properly. > > Change any of the coax lengths after the tuner, INCLUDING THOSE INSIDE > THE K3, by switching, exchange, or whatever, and what just barely got > tuned the last time by the same tuner may not now tune. > > Though this may not be your problem at all, a friend of mine was > having troubles of this mysterious sort. Eventually he discovered that > he had not soldered either the braid OR the center conductor on a > PL259. It worked for YEARS before it finally started getting > intermittent. > > Another ham had a balun that was gradually going bad and overheating, > apparently shorting some turns and causing mysterious changes in SWR. > He discovered that because during a QRO contest it caught fire and > completely shorted out. Actually his wife discovered it looking out > the window at the tower out in the field, and came and told him his > tower was on fire. > > The way to validate and check out one of these compromise antennas, is > to run it when it is brand new and working spiffy. SWEEP the MFJ > CONTINUOUSLY from the bottom of the lowest band to the top of the > highest band. Note the actual resonances you find along the way. > Write down those frequencies, the R at those resonant frequencies, and > the 2:1 SWR points above and below all of those resonances. Entirely > possible that all of the resonances are outside the ham bands. Keep > these figures as a reference. When you have trouble, repeat the > measurements. IF there is trouble in the antenna, those readings will > change. If the coax gets waterlogged, the 2:1 SWR points will broaden > out significantly and the R values at resonance will likely change. > If something gets broken the resonances will all move on you. > > If you have an AIM 4170 as your analyzer, just sweep it from 0.5 to 30 > MHz and save the file. You can then import it and have an onscreen > compare between the old and new readings. > > 73, Guy. > ______________________________________________________________ > 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 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 |
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