Re: [Elecraft] A Good Antenna Length?
Thank you for all the input. Antennas are a fun thing to talk about and something every one seams to enjoy and building their own, like I do. I had many wires antennas in the last 46 years. I am still learning. One thing I have not done is get a computer program for my Apple Computer and an antenna analyzer with software for it. So I do every thing trial and error. So far I found that the KX3 and KXPA100 internal tuner seams to be as good or better than the MFJ 989B that I had for many years. there were 2 tuners that were as good or better than this back in the day. Tuners have not changed much since then except for the introduction of auto tuners. I have a MFJ 998RT that I blew up on 160M with 500 watts MFJ replaced it for free. They shipped me a new one and I have not even opened the box. With that said, I have been searching for that antenna that will tune 160-6 meters and found out on this forum it does not exist. I never attempted to do this type of search. I now know why Wayne had stated that in Digest 123 Issue 6 about 3rd harmonics on the same coax. Jim Borwn comments are words of wisdom to stand by. I try to stay away from baluns as much as possible. Hairpin matches seams to be the best route, and I had proved that with tests on and spots on RBN. I have to go to work now and will be gone for a couple of days and I know I can add more to this. Took me a while to go through all the comments, and I had forgotten some of them. so my apologies for not mentioning them. Thank you for all your help. -- Jim K9TF __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
We are well past the posting limit for a single topic. Let's give this one a rest for now. 73, Eric List Moderator etc. elecraft.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Hi Guy same thing here I was going to use it on 160 but really like 75 makes a good DX antenna and when the band is open I have no problems breaking pileups,,, up 40 Ft and out ? Horz works OK on all other harmonic related bands ,,, did run some tests with a station 30 miles from me. I used to use a tuner at the base but I find the HB antenna tuner in the shack works well ,,,So what the heck ,,, Use a series of ferrites on the coax feed and run the feed about 50 Ft through the basement to the shack not a QRP antenna ? use a Heath amp drive it wit a K3 bottom line put up some wire and get on the air Bob K3DJC On Sat, 5 Jul 2014 16:08:19 -0400 Guy Olinger K2AV writes: > An end-fed half wave inverted L (EFHWL) done properly works very > well. It > needs to be tuned at the base of the wire against ground. > > An EFHWL for 80m is an excellent antenna that has no nulls and has > vertically polarized low angle radiation equal to a decent 1/4 wave > vertical. The horizontal wire fills in the general pattern to a > hemisphere > with a broad and mild null in the direction of the horizontal pull. > It is > an ideal all-distance contest antenna, because there are no holes > in > coverage in any direction or elevation. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
An end-fed half wave inverted L (EFHWL) done properly works very well. It needs to be tuned at the base of the wire against ground. An EFHWL for 80m is an excellent antenna that has no nulls and has vertically polarized low angle radiation equal to a decent 1/4 wave vertical. The horizontal wire fills in the general pattern to a hemisphere with a broad and mild null in the direction of the horizontal pull. It is an ideal all-distance contest antenna, because there are no holes in coverage in any direction or elevation. I have used this antenna at 1.5 kW off and on across 50 years with excellent results. The current max is at the bend, with a high resistance feed at the ground, making the effective series resistance of the grounding system of no consequence. Even a completely pathetic 100 ohm ground at the base does little damage against a 1000-2000-3000 ohm feedpoint for the wire. It IS uncommon and requires tuning at the base of the antenna, and that network requires components usually found in the output tuning networks of tube based QRO amplifiers. You can't feed the base of the antenna directly from coax without a tuner, and you can't buy the tuner off the shelf anywhere. With some DPST relays, coil stock and a single well-chosen fixed value QRO transmit capacitor, the antenna + tuning mechanism can cover the entire 3.5-4 ham band with less than 1.5:1 SWR anywhere. With some further work in the tuning mechanism, and attention to a proper 160m counterpoise, the wire will work well on 160-80-40-30 with distance from any tower(s). In my experience with that over the years, the EFHWL always beat an 80 dipole or inverted vee for DX and was as good as or beat dipole and vee for local and mid range. A 4-square would beat the EFHWL for DX. 73, Guy. On Sat, Jul 5, 2014 at 1:10 PM, WILLIS COOKE via Elecraft < elecraft@mailman.qth.net> wrote: > Off center fed dipoles, Windoms and end fed half waves are primarily low > power if not QRP antennas where you can do poorly with any antenna. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Jim, What you say can be correct. However, this need not happen all the time. When common mode issues arise one of the problems is that the wrong type of balun was chosen. Voltage baluns suffer when the VSWR gets too high. What you really need to use on these types of antennas is a current type balun. They have less of a problem than do the voltage type. I use a Carolina Windom here. That means I use a voltage type balun at the feed point, deliberately causing radiation from the shield of the vertical section of feed coax. 18 feet bellow the antenna feed point I place a 1:1 current balun, an RF choke, to prevent common mode problems. I have not had problems with common mode currents with this arrangement, and it will work at higher powers than the 100 Watts I normally use so long as the baluns and coax are rated for the power level you plan to run. 73, Barry K3NDM - Original Message - From: "jim" To: "elecraft" Sent: Saturday, July 5, 2014 10:24:19 Subject: Re: [Elecraft] A Good Antenna Length? On 7/5/2014 2:05 AM, David Cutter wrote: > You might consider an off-centre-fed dipole with appropriate balun and > choke. Not if you're going to run power. An off center fed antenna generates high common mode voltage, which will fry even the best choke when running power. I wouldn't consider such an antenna at greater than 100W. 73, Jim K9YC __ 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 Message delivered to k3...@comcast.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Try here: http://www.dj0ip.de/cmc-test/results-test-data/ P-T On 5 July 2014 20:45, Dick, K2ZR wrote: > Where can I find the results comparing these 4 antennas? > http://www.dj0ip.de/cmc-test/the-antennas/ > Thanks and 73, > Dick, K2ZR > -Original Message- > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of David > Cutter > Sent: Saturday, July 05, 2014 1:30 PM > To: elecraft@mailman.qth.net; j...@audiosystemsgroup.com > Subject: Re: [Elecraft] A Good Antenna Length? > > Rick DJ0IP has performed many hundreds of cmc measurements over the last > year or so. He has yet to publish his complete findings but here is a > taste: > http://www.dj0ip.de/cmc-test/ > http://www.dj0ip.de/cmc-test/the-components/the-baluns/ > http://www.dj0ip.de/cmc-test/pre-test-preparation/ > http://www.dj0ip.de/cmc-test/results-test-data/ant-1-b0/ > http://www.dj0ip.de/cmc-test/test-configurations/ > http://www.dj0ip.de/cmc-test/results-test-data/ant-2-b5/ > > > After many hundreds of measurements he has demonstrated that with a *dual > core* Guanella 4:1 balun at the feed point, common mode current can be tamed > even with deliberately poor antenna and feeder layout. > > There are not many folks who would take the care and have the patience to do > this sort of work. > > David > G3UNA > > > > > > > - Original Message - > From: "Jim Brown" > To: > Sent: Saturday, July 05, 2014 3:24 PM > Subject: Re: [Elecraft] A Good Antenna Length? > > >> On 7/5/2014 2:05 AM, David Cutter wrote: >>> You might consider an off-centre-fed dipole with appropriate balun and >>> choke. >> >> Not if you're going to run power. An off center fed antenna generates high > >> common mode voltage, which will fry even the best choke when running >> power. I wouldn't consider such an antenna at greater than 100W. >> >> 73, Jim K9YC > > __ > 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 > Message delivered to k...@arrl.net > > __ > 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 > Message delivered to p...@ieee.org __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Where can I find the results comparing these 4 antennas? http://www.dj0ip.de/cmc-test/the-antennas/ Thanks and 73, Dick, K2ZR -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of David Cutter Sent: Saturday, July 05, 2014 1:30 PM To: elecraft@mailman.qth.net; j...@audiosystemsgroup.com Subject: Re: [Elecraft] A Good Antenna Length? Rick DJ0IP has performed many hundreds of cmc measurements over the last year or so. He has yet to publish his complete findings but here is a taste: http://www.dj0ip.de/cmc-test/ http://www.dj0ip.de/cmc-test/the-components/the-baluns/ http://www.dj0ip.de/cmc-test/pre-test-preparation/ http://www.dj0ip.de/cmc-test/results-test-data/ant-1-b0/ http://www.dj0ip.de/cmc-test/test-configurations/ http://www.dj0ip.de/cmc-test/results-test-data/ant-2-b5/ After many hundreds of measurements he has demonstrated that with a *dual core* Guanella 4:1 balun at the feed point, common mode current can be tamed even with deliberately poor antenna and feeder layout. There are not many folks who would take the care and have the patience to do this sort of work. David G3UNA - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 3:24 PM Subject: Re: [Elecraft] A Good Antenna Length? > On 7/5/2014 2:05 AM, David Cutter wrote: >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running > power. I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC __ 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 Message delivered to k...@arrl.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Rick DJ0IP has performed many hundreds of cmc measurements over the last year or so. He has yet to publish his complete findings but here is a taste: http://www.dj0ip.de/cmc-test/ http://www.dj0ip.de/cmc-test/the-components/the-baluns/ http://www.dj0ip.de/cmc-test/pre-test-preparation/ http://www.dj0ip.de/cmc-test/results-test-data/ant-1-b0/ http://www.dj0ip.de/cmc-test/test-configurations/ http://www.dj0ip.de/cmc-test/results-test-data/ant-2-b5/ After many hundreds of measurements he has demonstrated that with a *dual core* Guanella 4:1 balun at the feed point, common mode current can be tamed even with deliberately poor antenna and feeder layout. There are not many folks who would take the care and have the patience to do this sort of work. David G3UNA - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 3:24 PM Subject: Re: [Elecraft] A Good Antenna Length? On 7/5/2014 2:05 AM, David Cutter wrote: You might consider an off-centre-fed dipole with appropriate balun and choke. Not if you're going to run power. An off center fed antenna generates high common mode voltage, which will fry even the best choke when running power. I wouldn't consider such an antenna at greater than 100W. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
I was using QRP, 3 Watts from the KX3, and I tend to use less than 5W CW on most bands. Even on receive it performed poorly, which is why I wnt back to a dipole. Cheers - Dave (G0DJA) - Original Message - To: Dave ; elecraft@mailman.qth.net Sent: Saturday, July 05, 2014 5:10 PM Subject: Re: [Elecraft] A Good Antenna Length? Off center fed dipoles, Windoms and end fed half waves are primarily low power if not QRP antennas where you can do poorly with any antenna. They are prone to arcing, heating and RF where you don't want it. You are better off with conventional low radiation resistance antennas if you plan to use 100 watts or higher. The search for an antenna that will make QRP sound like a kilowatt is futile. The only way to do that is to have excellent conditions and infinite patience which will make anything sort of work. Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
I have always found the the OCF antennas require a sufficient amount of feedline to mask the weird impedances it has. I have successfully used 135 foot 33% offset fed 4:1 balun with W1JR choke and >100 feet of coax necessary. I tried to use 22 feet and it was a total loss. All with <100 watts of course like Jim suggests. The added length does not add enough loss to account for the change. Mel, K6KBE On Saturday, July 5, 2014 9:50 AM, Dave wrote: I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. Even on 40M it didn't seem very good and I was plagued with RF getting into PCs and them shutting down or periferals stopping working. Plus, despite the hype, it didn't really seem to work well on other bands. The Antenna analyser was very dismissive, showing resonances outside of the Amateur bands and, on some that it was supposed to work on, no sign of any resonance at all. Dave (G0DJA) - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 2:24 PM Subject: Re: [Elecraft] A Good Antenna Length? > On 7/5/2014 2:05 AM, David Cutter wrote: >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running > power. I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC > __ > 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 > Message delivered to d...@g0dja.co.uk __ 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 Message delivered to farrerfo...@yahoo.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Lots of guys have good results with OCF dipoles all over the world. I run a weekly nationwide net for a Brand X radio model using a 40-6 meter OCF dipole. I am the loud signal and I hear all and they all hear me. Of course it helps I am in the Midwest, but still, I run 700 watts into it and NO CMC or other problems. I can run more power, but don't because that is enough to get the job done. Power is not an issue on my OCF dipole. Best advice I ever received on OCF Dipoles comes from a guy who tested several OCF dipoles for common mode noise, and then found the right type of balun/choke to use. IT DOES make a difference how you build and deploy it. If you run the feed line closer to one side than the other, you get CMC. If you use the wrong balun, you get CMC. See here: http://www.dj0ip.de/cmc-test/ Using a proper DUAL Core balun - where the transformer is wound on a separate toroid from the choke wound on another toriod - it works fine and you have no CMC noise issue. Stop by my shack and have a listen. CMC "can" be a problem if you allow it to be, but not if you pay attention to what you are doing. Again, don't believe me... stop by the shack or join my net some Wed evening and see. (We don't care what brand rig you own - its is ham radio and it is all good) Just MY take. This antenna works better than the AlphaDelta and home brew fan dipoles I used to use... (although I cannot explain why the others did not work as well, they should have...but who knows what they were coupling with in my crowded little lot.) Happy days. - K8JHR -- On 7/5/2014 12:50 PM, Dave wrote: I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart On , WILLIS COOKE wrote: Off center fed dipoles, Windoms and end fed half waves are primarily low power if not QRP antennas where you can do poorly with any antenna. They are prone to arcing, heating and RF where you don't want it. You are better off with conventional low radiation resistance antennas if you plan to use 100 watts or higher. The search for an antenna that will make QRP sound like a kilowatt is futile. The only way to do that is to have excellent conditions and infinite patience which will make anything sort of work. Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart On Saturday, July 5, 2014 11:55 AM, Dave wrote: I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. Even on 40M it didn't seem very good and I was plagued with RF getting into PCs and them shutting down or periferals stopping working. Plus, despite the hype, it didn't really seem to work well on other bands. The Antenna analyser was very dismissive, showing resonances outside of the Amateur bands and, on some that it was supposed to work on, no sign of any resonance at all. Dave (G0DJA) - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 2:24 PM Subject: Re: [Elecraft] A Good Antenna Length? > On 7/5/2014 2:05 AM, David Cutter wrote: >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running > power. I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC > __ > 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 > Message delivered to d...@g0dja.co.uk __ 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 Message delivered to wrco...@yahoo.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Off center fed dipoles, Windoms and end fed half waves are primarily low power if not QRP antennas where you can do poorly with any antenna. They are prone to arcing, heating and RF where you don't want it. You are better off with conventional low radiation resistance antennas if you plan to use 100 watts or higher. The search for an antenna that will make QRP sound like a kilowatt is futile. The only way to do that is to have excellent conditions and infinite patience which will make anything sort of work. Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart On Saturday, July 5, 2014 11:55 AM, Dave wrote: I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. Even on 40M it didn't seem very good and I was plagued with RF getting into PCs and them shutting down or periferals stopping working. Plus, despite the hype, it didn't really seem to work well on other bands. The Antenna analyser was very dismissive, showing resonances outside of the Amateur bands and, on some that it was supposed to work on, no sign of any resonance at all. Dave (G0DJA) - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 2:24 PM Subject: Re: [Elecraft] A Good Antenna Length? > On 7/5/2014 2:05 AM, David Cutter wrote: >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running > power. I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC > __ > 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 > Message delivered to d...@g0dja.co.uk __ 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 Message delivered to wrco...@yahoo.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. Even on 40M it didn't seem very good and I was plagued with RF getting into PCs and them shutting down or periferals stopping working. Plus, despite the hype, it didn't really seem to work well on other bands. The Antenna analyser was very dismissive, showing resonances outside of the Amateur bands and, on some that it was supposed to work on, no sign of any resonance at all. Dave (G0DJA) - Original Message - From: "Jim Brown" To: Sent: Saturday, July 05, 2014 2:24 PM Subject: Re: [Elecraft] A Good Antenna Length? On 7/5/2014 2:05 AM, David Cutter wrote: You might consider an off-centre-fed dipole with appropriate balun and choke. Not if you're going to run power. An off center fed antenna generates high common mode voltage, which will fry even the best choke when running power. I wouldn't consider such an antenna at greater than 100W. 73, Jim K9YC __ 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 Message delivered to d...@g0dja.co.uk __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Hello, I can recommend reading the following: http://hamwaves.com/cl-ocfd/index.html The high common-mode signals are apparently well attended to. Per-Tore / LA7NO On 5 July 2014 16:24, Jim Brown wrote: > On 7/5/2014 2:05 AM, David Cutter wrote: >> >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running power. > I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC > __ > 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 > Message delivered to p...@ieee.org __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
On 7/5/2014 2:05 AM, David Cutter wrote: You might consider an off-centre-fed dipole with appropriate balun and choke. Not if you're going to run power. An off center fed antenna generates high common mode voltage, which will fry even the best choke when running power. I wouldn't consider such an antenna at greater than 100W. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
You might consider an off-centre-fed dipole with appropriate balun and choke. A dual core balun that gives good cancellation of common mode currents at the feed point is essential and some folks add another choke on the ground with ground spike on the house side to drain off residual cmc. If you are particularly prone to local noise pickup on your long runs of coax, then another choke at the entry to your house is a good move. Coverage of 160 to 6 is possible but the baluns and chokes need attention to cover that range, especially if suspended and running power unless sturdily supported. Inverted V is easiest. You might not get all the coverage you want in one wire but you can join another ocfd onto the original to get more coverage on difficult bands. The ocfd gives your matching unit an easier time, ie reduced losses. Running your radio without a linear means you can have a lightweight aerial with small balun on fibreglass pole. These gents have done a huge amount of work: http://hamwaves.com/cl-ocfd/ and here http://www.dj0ip.de/off-center-fed-dipole/ http://www.dj0ip.de/off-center-fed-dipole/80m-ocf/ and try the user group: www.windom_ante...@yahoogroups.com 73 David G3UNA - Original Message - From: "Jim GM" To: "Elecraft" Sent: Friday, July 04, 2014 10:21 PM Subject: [Elecraft] A Good Antenna Length? What antenna lengths are you using on 160M with your KX3 or KXPA100 internal tuner? What is best for 160-6 meters? I like making my own antennas with wire. I usually have to give up one band or another cause it just would not tune up on a certain band. I have tried to stay with in these guide lines. -- Jim K9TF __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Been there, done that one too. Hamfest in Concordia, KS back in the early 80's just after I retired from the Army. Used an old Ten-Tec Argonaut and loaded the entire gutter system at the motel the hamfest was held at. There was so much corrosion in the joints that even the 5 watt Argonaut wiped out TV reception throughout the whole motel. Worked a whole bunch of stations on 20 meters too. Good thing they never figured out where the problem was coming from - LOL! Jim - W0EB -- Original Message -- From: "Wayne Burdick" To: "Nr4c" Cc: "Elecraft" ; "Jim GM" Sent: 7/4/2014 6:20:40 PM Subject: Re: [Elecraft] A Good Antenna Length? On Jul 4, 2014, at 4:01 PM, Nr4c wrote: I once worked a friend who'd just moved and was using a "GutterTron" ant in the CQWW. Yeah, the gutter and downspout fed against a ground-rod. Another friend loaded up the liner in his chimney, called a GutterTron. I worked all over the country on 10 and 15 meters recently using a large metal window frame (5' x 8' picture window) as the antenna. I used alligator clips directly from the KX3 to two spots on the frame, experimenting with spacing. This is not described in the literature, but it worked. The ATU tuned up the window frame to ~1.0:1 on 20-6 meters. Wayne N6KR __ 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 Message delivered to w...@cox.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Hi All, When in Key West I have little space for antennas. I built a simple Off Center Fed 40M Windom [ 67/33 or about 44' & 22' ]. The long element is a 15' off of the ground while the short element that is not much higher goes up to the peak of my QTH and back down to the other side of my deck. My K2/100 - KAT100 generally runs 75W & I've had great success with this antenna on every band 40-10. For 80M and 160M I alligator clip an 8' piece of wire from the end of the short element to my gutter system with provides another 80' of metal to the antenna. Do I burn up 160 & 80, not big time no but, I make contacts on both bands. In addition, if you ask me what I do for a ground: It's a 40' piece of #14 wire connected to a 2' piece of copper ground rod. Key West is a rock and it's tough to get down any further. Is my 40M Windom Gutter/Rube Goldberg Contraption a dummy load, no! I have the K2ZR/4 contest wallpaper and logs full of contacts to prove it. It 'taint perfect but you do what ya gotta do. And, if the bands are in lousey shape I ride my bike 5 minutes to my shady spot at Fort Zachory Taylor Beach and play some tunes on my Taylor Big Baby guitar. Life is good! 73, Dick K2ZR Niagara County, NY Mid-May to Mid December Ricardo en Cayo Hueso K2ZR/4 Key West, "The End Of The Road" IOTA NA-062 Mid-December - Time to go to Dayton The Southernmost Ham Shack In The Continental USA -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Nr4c Sent: Friday, July 04, 2014 7:01 PM To: Jim GM Cc: Elecraft Subject: Re: [Elecraft] A Good Antenna Length? Oops, Jim I use two antennas here at my place. For 80 and 160 I use a 170 foot long wire running from just over my feed line entry to a point 40 ft below a branch on a 75 ft pine, up to to the branch and over to another tree ( kinda like a "Z"). This is fed to an "L Match" made from a section of coil and a variable capacitor for 80 and I add an additional fixed cap for 160. For higher bands I have a 40-20-10 meter "fan" dipole that my K-Line (& my KX3-Line") will tune on 40-20-17-15-12-10-6 meters. Many will say "it can't work" but please don't tell my radios! The Elecraft tuners can tune anything! I once worked a friend who'd just moved and was using a "GutterTron" ant in the CQWW. Yeah, the gutter and downspout fed against a ground-rod. Another friend loaded up the liner in his chimney, called a GutterTron. Have fun. Try anything. It just might work. You can make a lot of antennas from a $45.00 spool of THHN and plastic "cutting" board from Walmart. About 2/3rds the price of a G5RV. Sent from my iPhone ...nr4c. bill > On Jul 4, 2014, at 5:21 PM, Jim GM < <mailto:jim.gmfo...@gmail.com> jim.gmfo...@gmail.com> wrote: > > What antenna lengths are you using on 160M with your KX3 or KXPA100 > internal tuner? What is best for 160-6 meters? I like making my own > antennas with wire. > > I usually have to give up one band or another cause it just would not > tune up on a certain band. > > I have tried to stay with in these guide lines. > > -- > Jim K9TF > __ > Elecraft mailing list > Home: <http://mailman.qth.net/mailman/listinfo/elecraft> http://mailman.qth.net/mailman/listinfo/elecraft > Help: <http://mailman.qth.net/mmfaq.htm> http://mailman.qth.net/mmfaq.htm > Post: <mailto:Elecraft@mailman.qth.net> mailto:Elecraft@mailman.qth.net > > This list hosted by: <http://www.qsl.net> http://www.qsl.net Please help support this email > list: <http://www.qsl.net/donate.html> http://www.qsl.net/donate.html Message delivered to > <mailto:n...@widomaker.com> n...@widomaker.com __ Elecraft mailing list Home: <http://mailman.qth.net/mailman/listinfo/elecraft> http://mailman.qth.net/mailman/listinfo/elecraft Help: <http://mailman.qth.net/mmfaq.htm> http://mailman.qth.net/mmfaq.htm Post: <mailto:Elecraft@mailman.qth.net> mailto:Elecraft@mailman.qth.net This list hosted by: <http://www.qsl.net> http://www.qsl.net Please help support this email list: <http://www.qsl.net/donate.html> http://www.qsl.net/donate.html Message delivered to <mailto:k...@arrl.net> k...@arrl.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
102 feet. There is nothing magic about 102 feet if you feed it with open-wire line. Having a decent match at the feed point doesn't mean squat because feed-point impedance is transformed by the feed line and what you get at the transmitter end won't be the same as at the feed point unless feed-line length is an even multiple of a half wavelength. What IS important is the total length of one half of your dipole plus your open-wire feed. For whatever frequency/frequencies you want an easy match on, make half of your dipole plus feed length as close to an odd multiple of a quarter wavelength as you can. This can be problematic if you want to operate on multiple bands. Don't despair--it's not that hard. You can adjust flat-top length or feed-line length or both to get something you can match on all your bands of interest. Bottom line. Your ability to match is affected by both dipole length and (open-wire) feed-line length. 73, Hank, W6SX __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
That's what I use... about 103 feet... and gives reasonable match on all bands. Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ/ PJ4HZ/ VP5HZ Owner - Operator Big Signal Ranch Staunton, Illinois email: b...@wjschmidt.com -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wayne Burdick Sent: Friday, July 04, 2014 6:15 PM To: Jim GM Cc: Elecraft Subject: Re: [Elecraft] A Good Antenna Length? Jim, Try 102 feet (or so) for each leg of a dipole fed with twinlead or open-wire line. This is not a close multiple of a half-wave on any band from 160-6 meters, so it stands a chance of providing a reasonable match on all bands. If the internal tuners can't find a match on one or two bands, adjust the length of one or both sides by a couple of feet experimentally. It'll be slightly imbalanced if it ends up off-center-fed, but this won't have much practical impact. At my QTH I use a 4:1 balun (Elecraft BL2) right at the radio to feed this antenna. The BL2 also has a 4:1/1:1 switch. I use the 4:1 setting for all but one band, where the 1:1 setting makes it easier on the ATU. Note that if you don't get to a low SWR when you first tap ATU TUNE, tap again within 5 seconds and the tuner will try more LC combinations. This will nearly always provide a 2:1 or better match unless the antenna presents a very high impedance. The KXAT3 will match a wider range than the KXAT100. For safety reasons, our QRO ATUs put limits on the SWR they will try to match. Use a good ground at the station. If in your installation you experience any RFI at higher power, drop back to a lower level. 73, Wayne N6KR On Jul 4, 2014, at 2:21 PM, Jim GM wrote: > What antenna lengths are you using on 160M with your KX3 or KXPA100 > internal tuner? What is best for 160-6 meters? I like making my own > antennas with wire. > > I usually have to give up one band or another cause it just would not tune > up on a certain band. > > I have tried to stay with in these guide lines. > > -- > Jim K9TF > __ > 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 > Message delivered to n...@elecraft.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 Message delivered to b...@wjschmidt.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
A few years ago I took a cue from a usenet posting by Walt, W2DU, that stated that the 102 foot doublet of the G5RV is a good antenna on 80m when fed with twin/window lead and a tuner as it is 3/8 of a wavelength on that band. I carried it further and have a 204 foot doublet fed with 450 ohm window lead and a Palstar AT1500DT tuner and the apex around 40 feet above ground level and the ends around 20 feet.. It may or may not work with the K3's internal tuner as I've not tried feeding it with coax. It works very well for me on 160m, 80m, and 40m. At the moment I am also feeding it on the higher bands until I get dedicated wires up for those bands. As I understand it, the 3/8 wavelength on the lowest band avoids feeding it at the voltage loop so matching is easier. Having a 3/4 wavelength 80m and 1.5 wavelengths on 40m also matches easily in my experience. 73, Nate N0NB -- "The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true." Ham radio, Linux, bikes, and more: http://www.n0nb.us __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
On Jul 4, 2014, at 4:01 PM, Nr4c wrote: > I once worked a friend who'd just moved and was using a "GutterTron" ant in > the CQWW. Yeah, the gutter and downspout fed against a ground-rod. > > Another friend loaded up the liner in his chimney, called a GutterTron. I worked all over the country on 10 and 15 meters recently using a large metal window frame (5' x 8' picture window) as the antenna. I used alligator clips directly from the KX3 to two spots on the frame, experimenting with spacing. This is not described in the literature, but it worked. The ATU tuned up the window frame to ~1.0:1 on 20-6 meters. Wayne N6KR __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Jim, Try 102 feet (or so) for each leg of a dipole fed with twinlead or open-wire line. This is not a close multiple of a half-wave on any band from 160-6 meters, so it stands a chance of providing a reasonable match on all bands. If the internal tuners can't find a match on one or two bands, adjust the length of one or both sides by a couple of feet experimentally. It'll be slightly imbalanced if it ends up off-center-fed, but this won't have much practical impact. At my QTH I use a 4:1 balun (Elecraft BL2) right at the radio to feed this antenna. The BL2 also has a 4:1/1:1 switch. I use the 4:1 setting for all but one band, where the 1:1 setting makes it easier on the ATU. Note that if you don't get to a low SWR when you first tap ATU TUNE, tap again within 5 seconds and the tuner will try more LC combinations. This will nearly always provide a 2:1 or better match unless the antenna presents a very high impedance. The KXAT3 will match a wider range than the KXAT100. For safety reasons, our QRO ATUs put limits on the SWR they will try to match. Use a good ground at the station. If in your installation you experience any RFI at higher power, drop back to a lower level. 73, Wayne N6KR On Jul 4, 2014, at 2:21 PM, Jim GM wrote: > What antenna lengths are you using on 160M with your KX3 or KXPA100 > internal tuner? What is best for 160-6 meters? I like making my own > antennas with wire. > > I usually have to give up one band or another cause it just would not tune > up on a certain band. > > I have tried to stay with in these guide lines. > > -- > Jim K9TF > __ > 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 > Message delivered to n...@elecraft.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Oops, Jim I use two antennas here at my place. For 80 and 160 I use a 170 foot long wire running from just over my feed line entry to a point 40 ft below a branch on a 75 ft pine, up to to the branch and over to another tree ( kinda like a "Z"). This is fed to an "L Match" made from a section of coil and a variable capacitor for 80 and I add an additional fixed cap for 160. For higher bands I have a 40-20-10 meter "fan" dipole that my K-Line (& my KX3-Line") will tune on 40-20-17-15-12-10-6 meters. Many will say "it can't work" but please don't tell my radios! The Elecraft tuners can tune anything! I once worked a friend who'd just moved and was using a "GutterTron" ant in the CQWW. Yeah, the gutter and downspout fed against a ground-rod. Another friend loaded up the liner in his chimney, called a GutterTron. Have fun. Try anything. It just might work. You can make a lot of antennas from a $45.00 spool of THHN and plastic "cutting" board from Walmart. About 2/3rds the price of a G5RV. Sent from my iPhone ...nr4c. bill > On Jul 4, 2014, at 5:21 PM, Jim GM wrote: > > What antenna lengths are you using on 160M with your KX3 or KXPA100 > internal tuner? What is best for 160-6 meters? I like making my own > antennas with wire. > > I usually have to give up one band or another cause it just would not tune > up on a certain band. > > I have tried to stay with in these guide lines. > > -- > Jim K9TF > __ > 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 > Message delivered to n...@widomaker.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
On Jul 4, 2014, at 3:34 PM, Don Wilhelm wrote: > Why do you need a tuner with a well designed fan dipole. The lengths of each > set of wires can be trimmed to allow coax feed. > > I have 2 fan dipoles here, one for 20, 15, and 10 and another for 30, 17, and > 12 meters. Each fed with a single coax. > Restricting them to 3 bands simplifies the tuning difficulties associated > with interaction. Keeping the wires about 1 foot apart reduces that > interaction. > > I do not mix bands that are 3rd harmonic related on the same coax, it just > complicates things - in other words, I do not mix radiators for 80 and 30 on > the same coax, the same for radiators for 40 and 15 meters. > > The KISS principle applies. > > 73, > Don W3FPR > > On 7/4/2014 6:22 PM, Dad wrote: >> Why not consider a fan dipole. 160, 40, and 17 ?? Model it on an antenna >> program. You're still going to need a tunner . >> >> Sent from my iPhone >> >>> On Jul 4, 2014, at 2:21 PM, Jim GM wrote: >>> >>> What antenna lengths are you using on 160M with your KX3 or KXPA100 >>> internal tuner? What is best for 160-6 meters? I like making my own >>> antennas with wire. >>> >>> I usually have to give up one band or another cause it just would not tune >>> up on a certain band. >>> >>> I have tried to stay with in these guide lines. >>> >>> -- >>> Jim K9TF >>> __ >>> 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 >>> Message delivered to vwrace...@gmail.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 >> Message delivered to w3...@embarqmail.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 > Message delivered to n...@elecraft.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Why do you need a tuner with a well designed fan dipole. The lengths of each set of wires can be trimmed to allow coax feed. I have 2 fan dipoles here, one for 20, 15, and 10 and another for 30, 17, and 12 meters. Each fed with a single coax. Restricting them to 3 bands simplifies the tuning difficulties associated with interaction. Keeping the wires about 1 foot apart reduces that interaction. I do not mix bands that are 3rd harmonic related on the same coax, it just complicates things - in other words, I do not mix radiators for 80 and 30 on the same coax, the same for radiators for 40 and 15 meters. The KISS principle applies. 73, Don W3FPR On 7/4/2014 6:22 PM, Dad wrote: Why not consider a fan dipole. 160, 40, and 17 ?? Model it on an antenna program. You're still going to need a tunner . Sent from my iPhone On Jul 4, 2014, at 2:21 PM, Jim GM wrote: What antenna lengths are you using on 160M with your KX3 or KXPA100 internal tuner? What is best for 160-6 meters? I like making my own antennas with wire. I usually have to give up one band or another cause it just would not tune up on a certain band. I have tried to stay with in these guide lines. -- Jim K9TF __ 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 Message delivered to vwrace...@gmail.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 Message delivered to w3...@embarqmail.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
> Just does not have enough > isolation from ground. yet it presents a good match. Go figure. A dummy load presents a good match. It just doesn't get out well. Trying to have one antenna do 160-6 meters is just too much if you care about getting out. One antenna can do a fair job on two bands, sometimes, three if done right. But if you expect to have more than a dummy load on multiple bands, you need to plan on having multiple antennas. Gary __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Why not consider a fan dipole. 160, 40, and 17 ?? Model it on an antenna program. You're still going to need a tunner . Sent from my iPhone > On Jul 4, 2014, at 2:21 PM, Jim GM wrote: > > What antenna lengths are you using on 160M with your KX3 or KXPA100 > internal tuner? What is best for 160-6 meters? I like making my own > antennas with wire. > > I usually have to give up one band or another cause it just would not tune > up on a certain band. > > I have tried to stay with in these guide lines. > > -- > Jim K9TF > __ > 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 > Message delivered to vwrace...@gmail.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Jim, A lossy balun will provide a good match - just the same as a dummy load resistor provides a good match (that is a near 100% loss if you are considering the radiation capability). Everything that loads does not make a good radiator. 73, Don W3FPR On 7/4/2014 6:16 PM, Jim GM wrote: I have tried a 6:1 balun at the feed point of the inverted L. How ever it presents a significant loss while QRP with 5 W. Just does not have enough isolation from ground. yet it presents a good match. Go figure. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
I have tried a 6:1 balun at the feed point of the inverted L. How ever it presents a significant loss while QRP with 5 W. Just does not have enough isolation from ground. yet it presents a good match. Go figure. -- Jim K9TF __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] A Good Antenna Length?
Jim, Having one antenna to cover 160 meters through 6 meters is asking a *lot*. But I would suggest starting with a halfwave on the lowest frequency band. If that is a half wave on 160, then the pattern will begin to break into multiple lobes beginning at 20 meters and up. Whether those lobes will be in a favorable direction for you is a different question. Of course, you would feed such an antenna with open wire line or ladder line because those are relatively low loss and losses will increase as the SWR increases. The feedline will have a high SWR on some bands. The length of the feedline makes a big difference in the ability of any given tuner to resolve the impedance at the shack end. A few sessions with the TLW (Transmission Line for Windows) may be helpful in determining the best feedline length compromise that ends up with a usable impedance at the shack end for all bands considered. Of course it will be necessary to know the antenna feedpoint for each band to know how to find the impedance transformation that will be present at the shack end. Antenna modeling can answer that antenna feedpoint impedance question. If the feedpoint impedance at the shack end is out of range of the tuner being used, some additional capacitance or inductance placed either across the feedline or in series with it may be necessary to bring the impedance into a range that the tuner can handle. Thirdly, you need a good current mode choke (balun) to keep RF out of the shack and to provide a balanced to unbalanced transformation. Its impedance must be at least 10 times (more is better) the highest line impedance seen at the place that current mode choke is placed. All the above must be taken into consideration for any antenna. Yes, there is much more to your question than just the lengths of the radiator. Any answers that do not also include the type and length of the feedline may not be able to be duplicated given your particular physical situation. Antennas and feedlines are just like that. Of course an antenna whose feedpoint impedance is matched to the transmission line characteristic impedance can use any length of that feedline, but that is not the usual case for multiband antennas. You will likely have better luck with 2 antennas - one for the low HF bands and another for the upper HF bands - those are normally easier to deal with. The ideal is a resonant antenna for each band, or fan antennas covering multiple bands (I restrict those to 3 bands because the interaction makes tuning frustrating). Good luck on finding that "magic" length - many have tried over the years and all are compromises. 73, Don W3FPR On 7/4/2014 5:21 PM, Jim GM wrote: What antenna lengths are you using on 160M with your KX3 or KXPA100 internal tuner? What is best for 160-6 meters? I like making my own antennas with wire. I usually have to give up one band or another cause it just would not tune up on a certain band. I have tried to stay with in these guide lines. __ 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 Message delivered to arch...@mail-archive.com