Re: [Elecraft] [OT] High SWR on 20 and 40
Thanks for the input Guy, Actually, the lengths are just a result of me trying to get this antenna optimized for 40m with my Yaesu 840 and the MFJ unbalanced tuner. This is my first HF antenna, and I never intended for it to be a true multibander. And yes - it never performed well on 20m at all. I live on a small lot and can't get anything too high, so it was just a means to get on the air. It did well on 40m and 30m with the old setup, so more than anything, I am curious why the K2/KAT2 can't seem to tune it up on 40. 40/30/20 is all I'm interested in right now, so perhaps the half G5RV might be something I should explore?! I certainly would not be opposed to lopping 8 feet off each end of this antenna. Thanks again! Dave Guy, K2AV wrote: The 16 feet of window line makes me wonder if you're not trying to do a half-size G5RV, but got the top dimensions wrong. -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4403981.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
Hi Daniel! I too have a KX1/AT1, and in fact, noticed this issue on the KX1 before I was even done building the K2. I just hooked the KX1 back up, and I'm getting nearly the same results. 40m 8.1:1 30m 1.3:1 20m infinity:1 It's been a while since I've used it outside, but I used to hook it up directly to the dipole through the BL2 balun and I could get a great match on 40m and 30m. I am buying an antenna analyzer today. Not necessarily because I think it will solve this problem (if it does, that's great!) but I'm long overdue for one. 73, K8DJW -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4403006p4404025.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, It is of great interest that your KX1 tuner could handle the tuning if you connected it directly to the balun. Fact is that the KXAT1 range is quite limited due to only having 3 inductors and 3 capacitors to switch in and out trying to find a match - the KAT2 has 8 of each and has quite a wide range. What is the chance that you have a bad piece of coax or a bad barrel adapter in the coax line? Has your coax outside gotten water inside it? That is certainly a possibility if you did not seal the connectors - low loss foam coax can soak up a lot of water. Do you have a bad balun? (I had one that got water soaked this summer and quit on me giving high SWR indications). You might want to try a new length of coax without the balun - connect the coax directly to the ladder line. If that works, try adding back the balun, then add the original coax At some point, you will identify what is failing. 73, Don W3FPR djmd wrote: Hi Daniel! I too have a KX1/AT1, and in fact, noticed this issue on the KX1 before I was even done building the K2. I just hooked the KX1 back up, and I'm getting nearly the same results. 40m 8.1:1 30m 1.3:1 20m infinity:1 It's been a while since I've used it outside, but I used to hook it up directly to the dipole through the BL2 balun and I could get a great match on 40m and 30m. I am buying an antenna analyzer today. Not necessarily because I think it will solve this problem (if it does, that's great!) but I'm long overdue for one. 73, K8DJW No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.142/2623 - Release Date: 01/15/10 02:35:00 __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Hi Daniel and all, I have all four Elecraft rigs, including internal ATU's. The ATU in the KX1 is the least effective of all of them. While my K2 and K3 ATU's can tune my R7, which is optomized for around 7130 khz on 40 meters, to nearly flat on each end of the band (the R7 has fairly sharp tuning on 40 meters), the KX1 ATU struggles at each end of the band. I've borrowed a 2nd KX1, and gotten much the same result, so I don't think it is just my particular ATU. In such a small package, it's not hard to understand why the KX1 ATU might not be nearly as versatile. The ATU in the K3 is the best of any internal ATU I've ever had. The K2 ATU is also quite good. The ATU in my K1 does a fair job, but I've always been somewhat suspect that I might have a small problem with that ATU. Occasionally it acts like it doesn't want to activate. Since my R7 on 40 meters seems to be a good application for an ATU when doing wide excursions on the band, maybe it would be interesting to see (and plot) how each rig's ATU performs across the band. It's also interesting (to me at least) that my K3 ATU will tune the R7 on 80 meters. The K2 might do that, but I haven't tried it. Obviously the R7 is very inefficient on 75/80, but at least the radio seems happy. The bottom line for me is that the KX1 ATU is useful, but not very wide ranging. It may work better on some other types of antennas. I'm glad I have it, but some situations probably require an outboard unit that is more versatile. Since I use balanced feedline type antennas a lot when I am portable, I usually have an outboard tuner for that reason. I really like Z match tuners for QRP use. The NorCal BLT is a good one too. Dave W7AQK - Original Message - From: Daniel Paul Perez daniel.pe...@fshsociety.org To: elecraft@mailman.qth.net Sent: Friday, January 15, 2010 10:02 PM Subject: Re: [Elecraft] [OT] High SWR on 20 and 40 Dave, Thanks for posting this. I'm going through the exact same exercise with my KX-1 KXAT1 and Icom703+. Glad to know I'm not alone. The Icom is able to tune just fine and when I switch the KX1 does not tune all bands – not on 40M. The KX1 tuner is optimized for shorter lengths of wire. I too wanted to use one antenna for both radios. I wonder if the K2 is optimized for a shorter wire? I find the more coax I insert between the 4:1 balun and radio the better the Icom tunes and performs and the opposite for the Elecraft -- it then loses 80, 40, 30 and barely tunes 20. It’s really odd. I get perfect SWR with a dummy load and KX1. I'll try a few things over the next few days per Elecraft. But will be very interested in what you find. Is the window ladder line 450 ohm? Does Elecraft give guidance on how the tuners are optimized? Eighth to quarter wavelength? I want to be sure as you do that the max power goes out. Best, Daniel ad1p __ 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 __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, Have you tried putting a dummy load in line and seeing if the tuner will tune 1:1 with it? This might tell you if the problem is in the tuner. You could also place the load further along the coax and see if the problem disappears. My KAT2 can tune almost anything it seems, but it is possible that your bridge diodes got zapped and that would cause problems. 73, Julius n2wn djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW - Julius Fazekas N2WN Tennessee Contest Group http://www.k4ro.net/tcg/index.html Tennessee QSO Party http://www.tnqp.org/ Elecraft K2/100 #4455 Elecraft K3/100 #366 Elecraft K3#1875 -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4404398.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave and all, Are you aware that you can use both tuners in tandem? You can set the manual tuner quickly for a close match and then let the internal tuner refine the match. For instance, you have an antenna that is difficult to match, but you already have a list of setting for a close match (less than 3:1) on the manual tuner for that antenna - just turn to those settings and then let the KX1, K1, K2, K3 tuner clean up for a very ow SWR. 73, Don W3FPR The bottom line for me is that the KX1 ATU is useful, but not very wide ranging. It may work better on some other types of antennas. I'm glad I have it, but some situations probably require an outboard unit that is more versatile. Since I use balanced feedline type antennas a lot when I am portable, I usually have an outboard tuner for that reason. I really like Z match tuners for QRP use. The NorCal BLT is a good one too. Dave W7AQK __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Of course two tuners doubles the tuner losses. Tuner losses amount to 10 to 15% per tuner, sometimes higher. If you're not folding back power after the first tuner does its match and it's under about 1.8, don't bother. There is nothing real to be gained. If you need both tuners, the real need is for a better matched antenna or a single tuner with a wider matching range. 73 de Brian/K3KO Don Wilhelm wrote: Dave and all, Are you aware that you can use both tuners in tandem? You can set the manual tuner quickly for a close match and then let the internal tuner refine the match. For instance, you have an antenna that is difficult to match, but you already have a list of setting for a close match (less than 3:1) on the manual tuner for that antenna - just turn to those settings and then let the KX1, K1, K2, K3 tuner clean up for a very ow SWR. 73, Don W3FPR The bottom line for me is that the KX1 ATU is useful, but not very wide ranging. It may work better on some other types of antennas. I'm glad I have it, but some situations probably require an outboard unit that is more versatile. Since I use balanced feedline type antennas a lot when I am portable, I usually have an outboard tuner for that reason. I really like Z match tuners for QRP use. The NorCal BLT is a good one too. Dave W7AQK __ 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 __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
There is one benefit to a low match at the tranceiver. Most builtin power meters are only accurate at 1:1. If you're trying to ensure you are qrp and your transmitter measures output power to maintain that level you need to ensure the match is correct. jim ab3cv __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Brian, While all that is true, the operating convenience that is afforded by using that method can be more significant than the added loss - it all depends... An L network usually is a low loss tuner. All the Elecraft tuners are of the L network type, as are many other 'auto-tuners' The old link coupled tuners such as the Johnson Matchbox are also very low loss. The popular T networks can be very bad with multiple matching points, but they do have a very large range and bandswitch easily. Using a manual tuner to bring the SWR on a difficult to feed antenna down to a reasonable level and then refining the match with an internal auto-tuner provides the same convenience as operating with only the autotuner - and the manual tuner can be in a remote location. After all, matching networks at an antenna can be thought of as manual tuner whose tuning is not changed - it brings the impedance down to a level where it can be easily fed with coax, and a tuner in the shack provides the final match required for large excursions across the band. Yes, at HF, an SWR of 2:1 or less does not increase the coax loss enough to be significant. At VHF and UHF it does make a difference because the additional loss caused by SWR grows as the matched line loss increases, and matched line losses increase with increasing frequency. 73, Don W3FPR Brian Alsop wrote: Of course two tuners doubles the tuner losses. Tuner losses amount to 10 to 15% per tuner, sometimes higher. If you're not folding back power after the first tuner does its match and it's under about 1.8, don't bother. There is nothing real to be gained. If you need both tuners, the real need is for a better matched antenna or a single tuner with a wider matching range. 73 de Brian/K3KO Don Wilhelm wrote: Dave and all, Are you aware that you can use both tuners in tandem? You can set the manual tuner quickly for a close match and then let the internal tuner refine the match. For instance, you have an antenna that is difficult to match, but you already have a list of setting for a close match (less than 3:1) on the manual tuner for that antenna - just turn to those settings and then let the KX1, K1, K2, K3 tuner clean up for a very ow SWR. 73, Don W3FPR The bottom line for me is that the KX1 ATU is useful, but not very wide ranging. It may work better on some other types of antennas. I'm glad I have it, but some situations probably require an outboard unit that is more versatile. Since I use balanced feedline type antennas a lot when I am portable, I usually have an outboard tuner for that reason. I really like Z match tuners for QRP use. The NorCal BLT is a good one too. Dave W7AQK __ 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 __ 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 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.145/2626 - Release Date: 01/16/10 02:35:00 __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
There are many kinds and configurations of tuners, each one having differing weak spots. There is not a single one outside of military prices which does not have impedance ranges that are inappropriate for the particular tuner design. Some tuners use CONTINUOUSLY variable inductors AND capacitors to get around most of those blind spots but there will still be matching points where it can't be brought down. Often where circulating currents in that particular design MUST become so high as to destroy components or waste half the power or more . You can fit a hundred KX1's inside of the case of many tuners, so in the KX1, the overriding issue is to use a design that CAN be MINIATURIZED. That you have an auto tuner AT ALL in a KX1 is already on the wonderful side of remarkable. To criticize it for not having the range of a larger tuner with continuously variable components seems unfairly critical to an extreme. Tuners designed with switched components necessarily have a lumpy performance but are the only method that can be made small enough for internal use in a K2 or KX1, etc. None of these that I have seen will deal with 1000+ ohm loads. But the real root of the calling these no-match ranges a problem seems a lacking in basic antenna understanding. ANY wire with ANY feedpoint will have harmonically related frequency ranges where the feed impedance can go into the thousands of ohms. If you have put up a wire antenna for all band use and haven't MEASURED what these are for your antenna on intended frequencies of use, you are quite short of putting forward a reasonable case for a tuner not working or having poor design. Loading any antenna to all ham bands in any location with any miscellaneous conductors around REMAINS a very sticky problem. For sure, NOT among god-given rights, is that any auto-tuner in any rig (including a KX1) must able to tune ANY antenna to ALL bands in any circumstance and provide a 1:1 SWR. There is an antenna, manufactured for decades by BW, that is a folded dipole with with a feedline on one wire at the center, and a high power RF termination resistor on the other wire at center. The termination resistor prevents the nodes of very high feed Z, reducing the range of Z extremes to values easily matched across the spectrum. There are tens of thousands of these antennas in use over the world at military sites, embassies and other installations where frequency agility is important, particularly in spread-spectrum modes. The wasted watts on certain frequency ranges are made up for by removing the high-Z nodes at the feedpoint. That this is an entirely successful approach and design fulfilling a continuing need is proven by continued sales to this day. Designing a single antenna that does not have Hi-Z nodes on wide-spread wanted frequencies is a pastime that goes back to the dawn of radio, and continues to this day. G5RV's, 86 and 43 foot end-fed wires, off-center fed dipoles, are but a few of the answers, and each has characteristics here or there that make it unusable or less desireable in a given circumstance. If you can't match it, START WITH THE ANTENNA, THEN THE FEEDLINE. Random collections of elevated wire and feedline usually DON'T work everywhere. But if it doesn't work and you don't get it, you have a challenging and possibly highly entertaining education in front of you. Something like learning to play chess. Join the century-old society of antenna designers and tinkerers going back to Marconi and beyond. Dumping it on tuner manufactures is just so .. Never mind. 73, Guy. __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave - If an antenna suddenly changes its behavior, the cause is usually a broken connection somewhere, or a problem with the feedline, either shorted or open. So check these all first. It is easy for there to be a break in the ladder line, particularly if it uses a solid conductor that is hard to detect. Use an ohm metro from one end to the other. You should also look at the antenna with and without the balun (1:1) position) in place, the tuning shouldn't change a whole lot. If it does, look at the balun construction for a poor connection or bad solder joint. An antenna analyzer is a big help here, if you don't have one, I am sure that you can borrow one if you ask at a club meeting or speak up on the local repeater. Having said that, if everything is in good shape, the first thing I suggest that you do is to model the antennas and transmission line and see what impedances you can expect to see where. This will help you understand what to do to match the antenna or where there are problems. Otherwise you are pretty much flying blind. Get a good antenna modeling program, something like EZNEC, even the trial demo version will work for your case: http://www.eznec.com/ MMANA will work too and is free: http://www.smeter.net/antennas/mmana.php Model your antenna. You should see a reasonably low impedance on 80M, a high impedance on 40M, a moderate impedance on 30M, a high impedance on 20M, and well you should really do the modeling to get precise values. You will probably see a lot of loss on 80M as the antenna appears to be less than 0.1 wavelengths high. Anyway, record these values on the different bands. The 16 ft of ladder line acts as a transformer to transform the impedance. You can calculate what the transformation will be with transmission line program; TLW is included with the Antenna Book and is good; W9CF has a nice java based app on the web: http://fermi.la.asu.edu/w9cf/tran/ which you can also download and run locally. It is nice as it runs on any machine that runs Java. You can also see how to do the transformations by hand in the Antenna Book. Now, enter the antenna impedance values into the transmission line program and see where they get transformed. You will need to do this twice, once for the antenna - ladder line - coax run and once for the balun - coax - tuner run. Use the balun at 1:1 for the time being. You should try to borrow an antenna analyzer to verify your calculations, although with the high impedances the analyzer may not give too useful results. None of these will be exact, but they should be in the ball park and give you an idea of what you should be doing to get a match. This procedure will tell you what impedance you are expecting the tuners to tune. My guess is that it is within the range of your tuners and that you have a problem elsewhere, but do the math. If the impedance is outside the range you are expecting to tune, then you can change antenna or transmission line lengths until you get a match that is acceptable. That is far better than cutting and adding line and antenna lengths without an idea of what to expect. The 16 ft of ladder line will have different effects on different bands. On 80M the electrical length of the transmission line will be small and you won't see much transformation. It is pretty much equivalent to lengthening the antenna. You should still see a low to moderate impedance here that the tuner is capable of matching. On 40M you will see more effect, but I suspect that the impedance will still be very high, perhaps too high for the tuner to match. On 20M the line length is a quarter wave, which should transform the high antenna impedance to a low to moderate impedance which the tuner can match easily. The K-2 is pretty portable so you could try hooking it up to the antenna at the various junctions and see what happens. You should be able to get a match on 20M at the end of the ladder line. Try it with and without the balun in the 1:1 position. If that doesn't work, I suspect that you have problem in the K2 tuner or SWR circuit. You should be able to get an acceptable match with or without the balun, it won't be the same, but it should be close. You may or may not get a match here on 40M with the 1:1 balun, but you should get one with the 4:1 balun. While the first thing I Would do is look for shorts or opens or bad connections in the system, you should probably read the Antenna Book chapter on transmission lines to get a feel for what is happening to the impedance at the various transmission line junctions. Having encouraged you to measure and model, my gut feel is that you should be able to match this system with the K2 tuner and the 4:1 balun on all bands above 80M. I suspect that you have a problem in the antenna feedline and connections somewhere. Let us know how this all works out and if you have further questions, feel free to ask. - Duffey -- KK6MC James
Re: [Elecraft] [OT] High SWR on 20 and 40
Hi James, Thanks so much for the extremely informative reply! I will dig deep into a lot of your suggestions later tonight. I think I may have overcomplicated the issue, so let me see if I can give it a shakedown. First off, lets forget everything besides 40m. That's really the band I am concerned with first and foremost. Before Elecraft came into my life, I was using a Yaesu FT840 with an MFJ941E tuner. Coax (10' or so) out of the tuner, through the floor, into a barrel that goes through cementboard to the outside. From there, short coax up to a W2DU 4:1 current balun. Then 16' or so of windowline, and the dipole up about 20', about 67' long. I have a very restricted yard for antennas and just wanted to get on the air. Anyway, after some poking and prodding I was able to consistently tune up on 40m fairly well, 1.5 or less. I made several CW contacts across the country as well as Canada and South America. Then I built the KX1 with the autotuner, and was not able to get under 5:1 from the same point with all the same components in place. No big deal, I didn't intend on using the KX1 in the 'shack' anyway. But then I built the K2/KAT2, and was getting pretty much the same result. As it stands right now, I cannot break below 9.9:1 on the KAT2 on 40m from the shack. I've tried different coax types and lengths on each side of the barrel and have seen no improvement. Also, it doesn't matter which balun I use, or whether I select 1:1 or 4:1 on the BL2. Results are the same. Now, when I attach the K2 directly to the balun (now an Elecraft BL2) I can get a great match on 40m. As I can add a very short piece between the K2 and the balun with no ill effect, but once the coax is longer than about 5', the SWR shoots up. I picked up an analyzer today (259B). It's my first one, and I hardly know what I'm doing, but I can tell you right off the bat that whether I attach it to the coax in the shack, or directly to the balun, it's appearing to be resonant at the same 3 places. Around 10mhz, 20mhz, and 26mhz. If there is any other information you would like to know from the analyzer at any specific frequency and connnection point, please let me know. I hope this helps... I sincerely appreciate everyone's assistance. I'm still learning and it's nice to have a place to get good info and not made to feel like I'm an idiot. :drunk::confused: -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4403006p4406096.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
It sounds like you have a broken/shorted wire somewhere. For testing, could You run coax all the way to the antenna and see how that does? If you Antenna is insulated wire, don't overlook the possibility of a break in the Antenna itself. With 67 feet of wire, you should get a fairly decent 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, No, you are not an idiot, nor drunk, but you may be confused by the impedance transformation effects of a feedline. I suggest you take a look at the ARRL Handbook or Antenna Book chapter on Transmission Lines, especially the sections dealing with transmission line matching sections if you want an understanding of what is going on. The most common feedline matching section used by radio amateurs is the quarter wavelength section - that one is relatively easy to understand and the math is not complex. The underlying mechanism is that a low impedance at one end will transform to a high impedance at the other end. For example, if a 50 ohm electrical quarter wave of coax is used and one end is connected to a 100 ohm load, the other end will have the equivalent of a 25 ohm load - and if the far end of that same coax is shorted, it will have a very high impedance (theoretically infinity, but practically 4000 ohms) at the near end Any length of feedline (and any impedance feedline) that is not matched in its characteristic impedance at the load will act as an impedance transformer. It is nice to know the resonance points for your antenna system, but what is really needed is the impedance (both resistive and reactive) at the desired frequencies of operation. If we knew all your feedline parameters (type, velocity factor, precise length, etc) we could likely compute the impedance at any other frequency, but it is easier to just measure it since your MFJ259 provides you with a tool to do exactly that. There is no impedance transformation on a transmission line (of any length) at the points where the antenna is matched to that line - that is the situation at your resonance points if you only looked at the SWR to determine resonance. The actual resonance point of the antenna *system* is where the reactance goes to zero (or very low as indicated on the MFJ259) - then at the resonance points you would look at the resistive component - it is not likely to be 50 ohms. One other piece of information that may help your 40 meter situation is based on the fact that you can use the tuner successfully at the balun location - and that is that an electrical half wavelength of transmission line will repeat the impedance at each end - so if you connect a total of a half wavelength transmission line between the tuner and the balun, the tuner will tune it. A 40 meter electrical half wave of solid dielectric coax will be in the vicinity of 42 feet (VF+0.66, and the length of the foam dielectric coax will be close to 55.5 feet (VF+0.84). The lengths you have been trying are closer to a quarter wavelength. 73, Don W3FPR djmd wrote: I picked up an analyzer today (259B). It's my first one, and I hardly know what I'm doing, but I can tell you right off the bat that whether I attach it to the coax in the shack, or directly to the balun, it's appearing to be resonant at the same 3 places. Around 10mhz, 20mhz, and 26mhz. If there is any other information you would like to know from the analyzer at any specific frequency and connnection point, please let me know. I hope this helps... I sincerely appreciate everyone's assistance. I'm still learning and it's nice to have a place to get good info and not made to feel like I'm an idiot. :drunk::confused: __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
If you are really interested in 40M only, why on earth don't you simplify your life and get rid of the tuners, the ladderline and the BL2. Run coax from the antenna spigot on the radio to the antenna. Coil up a few turns of it at the feed point if you insist on a balun (I don't necessarily), trim the length of the wire for minimum SWR at your frequency of interest and get on and operate. Wes N7WS --- On Sat, 1/16/10, djmd d...@fuse.net wrote: From: djmd d...@fuse.net Subject: Re: [Elecraft] [OT] High SWR on 20 and 40 To: elecraft@mailman.qth.net Date: Saturday, January 16, 2010, 3:05 PM Hi James, Thanks so much for the extremely informative reply! I will dig deep into a lot of your suggestions later tonight. I think I may have overcomplicated the issue, so let me see if I can give it a shakedown. First off, lets forget everything besides 40m. That's really the band I am concerned with first and foremost. Before Elecraft came into my life, I was using a Yaesu FT840 with an MFJ941E tuner. Coax (10' or so) out of the tuner, through the floor, into a barrel that goes through cementboard to the outside. From there, short coax up to a W2DU 4:1 current balun. Then 16' or so of windowline, and the dipole up about 20', about 67' long. I have a very restricted yard for antennas and just wanted to get on the air. Anyway, after some poking and prodding I was able to consistently tune up on 40m fairly well, 1.5 or less. I made several CW contacts across the country as well as Canada and South America. Then I built the KX1 with the autotuner, and was not able to get under 5:1 from the same point with all the same components in place. No big deal, I didn't intend on using the KX1 in the 'shack' anyway. But then I built the K2/KAT2, and was getting pretty much the same result. As it stands right now, I cannot break below 9.9:1 on the KAT2 on 40m from the shack. I've tried different coax types and lengths on each side of the barrel and have seen no improvement. Also, it doesn't matter which balun I use, or whether I select 1:1 or 4:1 on the BL2. Results are the same. Now, when I attach the K2 directly to the balun (now an Elecraft BL2) I can get a great match on 40m. As I can add a very short piece between the K2 and the balun with no ill effect, but once the coax is longer than about 5', the SWR shoots up. I picked up an analyzer today (259B). It's my first one, and I hardly know what I'm doing, but I can tell you right off the bat that whether I attach it to the coax in the shack, or directly to the balun, it's appearing to be resonant at the same 3 places. Around 10mhz, 20mhz, and 26mhz. If there is any other information you would like to know from the analyzer at any specific frequency and connnection point, please let me know. I hope this helps... I sincerely appreciate everyone's assistance. I'm still learning and it's nice to have a place to get good info and not made to feel like I'm an idiot. :drunk::confused: -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4403006p4406096.html Sent from the [OT] mailing list archive at Nabble.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 __ 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
[Elecraft] [OT] High SWR on 20 and 40
Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4401077.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but whichever balun you are using, try the other one and see what happens. Do you have an antenna analyzer? or can you borrow one? If so, what is the impedance at the end of the coax? Both the resistive and reactive components please - just the SWR does not provide much information on how to advise you to proceed. You may be better off eliminating the coax entirely and running the window line all the way into the shack. 73, Don W3FPR djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
I think he would be better off throwing away the window line and eliminating the tuner. Cut the length of the dipole for resonance on 40M and then add a 20M dipole in parallel at the feed point. There will be some interaction, which can be lessened by orienting the dipoles at right angles to each other or at least getting some angular separation. Conventional wisdom (not always correct) says to use a 1:1 current balun at the antenna. With only 10W you don't want to be throwing it away in lossy tuners and mismatched transmission lines. Wes N7WS ps. The only tuner I use in my shack is the pi-net in my L4-B. --- On Fri, 1/15/10, Don Wilhelm w3...@embarqmail.com wrote: From: Don Wilhelm w3...@embarqmail.com Subject: Re: [Elecraft] [OT] High SWR on 20 and 40 To: djmd d...@fuse.net Cc: elecraft@mailman.qth.net Date: Friday, January 15, 2010, 1:45 PM Dave, Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but whichever balun you are using, try the other one and see what happens. Do you have an antenna analyzer? or can you borrow one? If so, what is the impedance at the end of the coax? Both the resistive and reactive components please - just the SWR does not provide much information on how to advise you to proceed. You may be better off eliminating the coax entirely and running the window line all the way into the shack. 73, Don W3FPR djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
It's the BL-2 switched balun that I have been using, and have tried both modes. Forgot that detail. I have also tried one of those baluns built from PVC - can't remember the manufacturer. It's a 1:1 as well. Same results. No analyzer yet, but I really should think about getting one. Planning on a lot of antenna experimentation this year. I have actually thought of eliminating the coax. I'm not sure if I can use the same route as the coax, with the metal window frames, gas pipe, water pipes, all nearby in the basement. But what about going right through the brick? I would not be opposed to doing something like this. And re: your follow up - all the testing was done with the KAT2. I have never disconnected it. I also should have mentioned that I do plan on using this antenna system with my old radio as well. Only 10w on the K2, but 50 or so with the Yaesu as well. (mostly digital and CW.) Don Wilhelm-4 wrote: Dave, Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but whichever balun you are using, try the other one and see what happens. Do you have an antenna analyzer? or can you borrow one? If so, what is the impedance at the end of the coax? Both the resistive and reactive components please - just the SWR does not provide much information on how to advise you to proceed. You may be better off eliminating the coax entirely and running the window line all the way into the shack. 73, Don W3FPR djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW __ 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 -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4402287.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
oh, and yes, I was definitely getting a 1:1 on the KAT2 between the radio and the dummy load. I put the dummy load in at all points and saw 1:1. -- View this message in context: http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4402311.html Sent from the [OT] mailing list archive at Nabble.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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, If you did not disconnect the KAT2, then please tell us the setup (all the connections) when you have SWR readings below 1.5. That may be capable of providing some sort of clue. 73, Don W3FPR djmd wrote: And re: your follow up - all the testing was done with the KAT2. I have never disconnected it. Don Wilhelm-4 wrote: Dave, Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but whichever balun you are using, try the other one and see what happens. Do you have an antenna analyzer? or can you borrow one? If so, what is the impedance at the end of the coax? Both the resistive and reactive components please - just the SWR does not provide much information on how to advise you to proceed. You may be better off eliminating the coax entirely and running the window line all the way into the shack. 73, Don W3FPR djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW __ 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 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.142/2623 - Release Date: 01/15/10 02:35:00 __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
The 16 feet of window line makes me wonder if you're not trying to do a half-size G5RV, but got the top dimensions wrong. It would be 51' (instead of 67 which is REALLY bad on 20 meters), or a little longer, say 54' if you wanted to load on 17m and 12m. My K2/10 and the auto tuner will match most anything, but your lengths are not anything I would do on purpose for multiband : ) On Fri, Jan 15, 2010 at 7:49 PM, Don Wilhelm w3...@embarqmail.com wrote: Dave, If you did not disconnect the KAT2, then please tell us the setup (all the connections) when you have SWR readings below 1.5. That may be capable of providing some sort of clue. 73, Don W3FPR djmd wrote: And re: your follow up - all the testing was done with the KAT2. I have never disconnected it. Don Wilhelm-4 wrote: Dave, Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but whichever balun you are using, try the other one and see what happens. Do you have an antenna analyzer? or can you borrow one? If so, what is the impedance at the end of the coax? Both the resistive and reactive components please - just the SWR does not provide much information on how to advise you to proceed. You may be better off eliminating the coax entirely and running the window line all the way into the shack. 73, Don W3FPR djmd wrote: Hello, I have been trying to troubleshoot my antenna system, and have been trying to avoid the dreaded high swr post, but I've run out of ideas, so I'm turning here. First let me explain my system. 67' dipole fed by 16' of window line. That's connected to an Elecraft balun. From the balun, there's a short piece of coax going to a barrel and into the basement (through a piece of cement backerboard. From inside the basement, there is another piece of coax, about 12', connected to the barrel, and going up into the bedroom directly to a K2 with an autotuner. Before the K2, I was using a Yaesu FT840 with an MFJ tuner. After tweaking the window line length and the actual length of the dipole, I never really had a problem with SWR (well, according to what the MFJ was saying, which may or may not be totally accurate.) Usually 1.5:1 or under on all bands. With the K2/KAT2 in place, the SWR reported by the tuner is all over the place. The only one that gets less than 1.5:1 is 30m. Most bands are pretty random, anywhere from 3:1 to 7:1. However, on 20 and 40, it generally does not get below 9.9:1. I've tried 4 different lengths of coax between the barrel (inside) and the rig... 3', 6', 12' 20'. I've tried a couple different lengths between the balun and the barrel on the outside. When I attach the balun directly to the K2 I get 1.3:1 on all bands (most are 1:1.) With a short piece of coax between the rig and the balun, I get the same results. I've also attached my dummy load to the barrel on the outside of the house, and tested it from the shack, and I saw 1:1 no problem. I totally understand the concept that if A works and B works, A+B doesn't necessarily work. I understand it's a whole system. But I've tried so many different combinations of coax on each side, and don't understand why my SWR is basically infinity:1 on 20 and 40, when they seemed to match reasonably with the old system. I have not tried different lengths of window line between the dipole due to the fact that I had it perfectly trimmed for my old system. But I have plenty of it and would be open to trying anything. Just trying to get the most I can out of my modest 10W. :) Any suggestions would be appreciated! 73, Dave K8DJW __ 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 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.142/2623 - Release Date: 01/15/10 02:35:00 __ 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 __ 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
[Elecraft] [OT] High SWR on 20 and 40
Dave, Thanks for posting this. I'm going through the exact same exercise with my KX-1 KXAT1 and Icom703+. Glad to know I'm not alone. The Icom is able to tune just fine and when I switch the KX1 does not tune all bands – not on 40M. The KX1 tuner is optimized for shorter lengths of wire. I too wanted to use one antenna for both radios. I wonder if the K2 is optimized for a shorter wire? I find the more coax I insert between the 4:1 balun and radio the better the Icom tunes and performs and the opposite for the Elecraft -- it then loses 80, 40, 30 and barely tunes 20. It’s really odd. I get perfect SWR with a dummy load and KX1. I'll try a few things over the next few days per Elecraft. But will be very interested in what you find. Is the window ladder line 450 ohm? Does Elecraft give guidance on how the tuners are optimized? Eighth to quarter wavelength? I want to be sure as you do that the max power goes out. Best, Daniel ad1p __ 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
Re: [Elecraft] [OT] High SWR on 20 and 40
Dave, Thanks for posting this. I'm going through the exact same exercise with my KX-1 KXAT1 and Icom703+. Glad to know I'm not alone. The Icom is able to tune just fine and when I switch the KX1 does not tune all bands – not on 40M. The KX1 tuner is optimized for shorter lengths of wire. I too wanted to use one antenna for both radios. I wonder if the K2 is optimized for a shorter wire? I find the more coax I insert between the 4:1 balun and radio the better the Icom tunes and performs and the opposite for the Elecraft -- it then loses 80, 40, 30 and barely tunes 20. It’s really odd. I get perfect SWR with a dummy load and KX1. I'll try a few things over the next few days per Elecraft. But will be very interested in what you find. Is the window ladder line 450 ohm? Does Elecraft give guidance on how the tuners are optimized? Eighth to quarter wavelength? I want to be sure as you do that the max power goes out. Best, Daniel ad1p __ 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
