PAR/LNR EFHW antenna
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I have one of the original PAR end fed half wave antennas prior to LNR taking over production and sales.
Everything is present EXCEPT the little matching network that couples the EFHW to the radio. I tried contacting LNR to obtain a new one but they told me that they couldn't do that, BUT they would sell me a new version of the complete antenna for the paltry sum of around $80! I said "no thanks" and hung up the phone. I am after the schematic or the best guess of the components and parts placement that will resonate this 40-30-20M antenna. It's not rocket science but it's close!! As I understand it these antennas are fairly high impedance wise, so I need some kind of matching network to bring that down to around 50 ohms for the KX2. Failing that path, has anyone hooked an EFHW to the internal ATU with good results? I would also include a cut to frequency ground radial that I would lay out below the antenna. That would be the easiest thing and simple to employ. Over the next 10-12 days I am planning on doing some portable operating from MD and PA. Taking the KX2 with me and hope to get some operating time between family obligations. Opinions, observations, ideas please. Vy 73 es gud DX! Rich Arland K7SZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Try a 64:1 balun. That's what our antenna expert at our club suggests for
resonant end fed antennas. On Mon, Jan 8, 2018 at 5:59 PM, Rich Arland <[hidden email]> wrote: > I have one of the original PAR end fed half wave antennas prior to LNR > taking over production and sales. > > > Everything is present EXCEPT the little matching network that couples the > EFHW to the radio. I tried contacting LNR to obtain a new one but they told > me that they couldn't do that, BUT they would sell me a new version of the > complete antenna for the paltry sum of around $80! I said "no thanks" and > hung up the phone. > > > I am after the schematic or the best guess of the components and parts > placement that will resonate this 40-30-20M antenna. It's not rocket > science but it's close!! As I understand it these antennas are fairly high > impedance wise, so I need some kind of matching network to bring that down > to around 50 ohms for the KX2. > > > Failing that path, has anyone hooked an EFHW to the internal ATU with good > results? I would also include a cut to frequency ground radial that I would > lay out below the antenna. That would be the easiest thing and simple to > employ. > > > Over the next 10-12 days I am planning on doing some portable operating > from MD and PA. Taking the KX2 with me and hope to get some operating time > between family obligations. > > > Opinions, observations, ideas please. > > > Vy 73 es gud DX! > > Rich Arland K7SZ > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > -- --- 72, Rich Hurd / WC3T / DMR: 3142737 PA Army MARS, Northampton County RACES, EPA-ARRL Public Information Officer for Scouting Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid: *FN20is* ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by RichA
I've had success with this unun on my K2/10 and a FT-897 at 100
watts/external tuner. Used a random length of wire tossed up in a tree, haven't tried to make one resonant. http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf 73, Dennis NJ6G On 1/8/2018 14:59, Rich Arland wrote: > I am after the schematic or the best guess of the components and parts placement that will resonate this 40-30-20M antenna. It's not rocket science but it's close!! As I understand it these antennas are fairly high impedance wise, so I need some kind of matching network to bring that down to around 50 ohms for the KX2. > > > Failing that path, has anyone hooked an EFHW to the internal ATU with good results? I would also include a cut to frequency ground radial that I would lay out below the antenna. That would be the easiest thing and simple to employ. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by rich hurd WC3T
Consider what W8JI says about end fed ants. He also addresses the PAR.
Interesting observation from one set of calcs he did- Maximum antenna current is .758 amperes, while the coax common mode current maximum is actually 1.02 amperes! https://www.w8ji.com/end-fed_1_2_wave_matching_system_end%20feed.htm Without a decent counterpoise, the Z you see could be anything. What you see will be a function of your particular counterpoise. Yes it can work with the KX2 with no coax feed line and those power levels. His remarks about using high power are interesting. 73 de Brian/K3KO On 1/8/2018 23:07 PM, rich hurd WC3T wrote: > Try a 64:1 balun. That's what our antenna expert at our club suggests for > resonant end fed antennas. > > On Mon, Jan 8, 2018 at 5:59 PM, Rich Arland <[hidden email]> wrote: > >> I have one of the original PAR end fed half wave antennas prior to LNR >> taking over production and sales. >> >> >> Everything is present EXCEPT the little matching network that couples the >> EFHW to the radio. I tried contacting LNR to obtain a new one but they told >> me that they couldn't do that, BUT they would sell me a new version of the >> complete antenna for the paltry sum of around $80! I said "no thanks" and >> hung up the phone. >> >> >> I am after the schematic or the best guess of the components and parts >> placement that will resonate this 40-30-20M antenna. It's not rocket >> science but it's close!! As I understand it these antennas are fairly high >> impedance wise, so I need some kind of matching network to bring that down >> to around 50 ohms for the KX2. >> >> >> Failing that path, has anyone hooked an EFHW to the internal ATU with good >> results? I would also include a cut to frequency ground radial that I would >> lay out below the antenna. That would be the easiest thing and simple to >> employ. >> >> >> Over the next 10-12 days I am planning on doing some portable operating >> from MD and PA. Taking the KX2 with me and hope to get some operating time >> between family obligations. >> >> >> Opinions, observations, ideas please. >> >> >> Vy 73 es gud DX! >> >> Rich Arland K7SZ >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] >> > > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Dennis Moore
Dennis, Mel and Rich:
Thanks for the quick replies. I have googled the EFHW and have some baseline info to play with. My original idea was to use the internal ATU of the KX2 coupled directly to antenna and put a counterpoise on the ground side of the a rig's antenna connector. I have the Super Antennas MP-1 with extra extension mast sections and a bunch of radials, so in the grand scheme of things if I can't get the EFHW to work properly I can revert to the MP-1. The QRP Guys have a neat little tuner that I might try. My parts bench stock has dwindled over the last few years and Radio Shack is no longer with us for parts and components, so it looks like I will be scrounging!! Vy 73 es gud DX! Rich Arland K7SZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by RichA
On 1/8/2018 16:59, Rich Arland wrote:
> Failing that path, has anyone hooked an EFHW to the internal ATU with good results? I would also include a cut to frequency ground radial that I would lay out below the antenna. That would be the easiest thing and simple to employ. That definitely will not work: The impedance of the EFHW is much to high for any internal ATU to match. The 64:1 balun may work, though I haven't tried one. QRPKITS has a QRP tuner, but it works only on a single band. Most any of the external antenna tuners will work, though they may be lossy. The best solution, I think, is to build your own L-network tuner. One coil, a 3-position switch, and one variable capacitor. You don't have to get a perfect match, just within the range of the internal ATU, like 3:1. Once you find the right coil tap positions, the internal ATU should be able to handle the small mismatch with different antenna installations, etc. It may seem like a lot of trouble, but if you can match the EFHW, it's just about the most effective simple wire antenna you can use. 73, Scott K9MA -- Scott K9MA [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by RichA
Steve, AA5TB, has a great piece on his site appropriately called How to Make an End Fed Half Wave Antenna Work. I have the EARCHI and I've built from Steve's guidance. I use them when trailer camping. Very happy with both.
Eric KE6US On 1/8/2018 2:59 PM, Rich Arland wrote: I have one of the original PAR end fed half wave antennas prior to LNR taking over production and sales. Everything is present EXCEPT the little matching network that couples the EFHW to the radio. I tried contacting LNR to obtain a new one but they told me that they couldn't do that, BUT they would sell me a new version of the complete antenna for the paltry sum of around $80! I said "no thanks" and hung up the phone. I am after the schematic or the best guess of the components and parts placement that will resonate this 40-30-20M antenna. It's not rocket science but it's close!! As I understand it these antennas are fairly high impedance wise, so I need some kind of matching network to bring that down to around 50 ohms for the KX2. Failing that path, has anyone hooked an EFHW to the internal ATU with good results? I would also include a cut to frequency ground radial that I would lay out below the antenna. That would be the easiest thing and simple to employ. Over the next 10-12 days I am planning on doing some portable operating from MD and PA. Taking the KX2 with me and hope to get some operating time between family obligations. Opinions, observations, ideas please. Vy 73 es gud DX! Rich Arland K7SZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]<mailto:[hidden email]> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by K9MA
I agree with what has Scott has written. EFHW from what I have read and experienced, generally have ~ 3000+ ohm impedance at feed point. Thus the need for an adequate transformer, most usually to match 50 Ohms. I use one on 160 and 80 meters (where it is really a full wave) at home by using a toroid and windings with a tap. I do use a tuner for slight changes when the length doesn't match the frequency I choose to use. A counter balance removes the idea and radiation of the EFHW. A very short ground is important to remove static potential on the low side of the coil to protect equipment. If you google EFHW's you will finds loads of great stuff to read and help you. Good luck.
I happen to like the ones I am using, but did buy a factory built coil after I found my personally built could not give a native match at the desired freq as my toroid did not have adequate specs despite what I had calculated would work. The site I got my initial info from was incorrect and the co I bought the toroid and wire from had an inadequate description. Live and learn. My home made works best on EFHW above 40 meters. My commercially built transformer in the 160 has very narrow bandwidth. A remotely operated tuner broadens it but efficiency is reduced once off the designed frequency. In the design is the selection of wire length and height into the matching transformer. I do have the multiband EFHW but that requires the appropriate wire length on each band. I carry the appropriate wires in my antenna kit inside the KX2 large case. The small gauge silk-like wire is also light and small. I have a super light 43' collapsible shore fishing pole to string out the wire, versus getting a launched wire stuck in a tree and then be potentially guilty of littering in the state park where I like to hang out. 73, Bill K9YEQ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of K9MA Sent: Monday, January 8, 2018 7:39 PM To: [hidden email] Subject: Re: [Elecraft] PAR/LNR EFHW antenna On 1/8/2018 16:59, Rich Arland wrote: > Failing that path, has anyone hooked an EFHW to the internal ATU with good results? I would also include a cut to frequency ground radial that I would lay out below the antenna. That would be the easiest thing and simple to employ. That definitely will not work: The impedance of the EFHW is much to high for any internal ATU to match. The 64:1 balun may work, though I haven't tried one. QRPKITS has a QRP tuner, but it works only on a single band. Most any of the external antenna tuners will work, though they may be lossy. The best solution, I think, is to build your own L-network tuner. One coil, a 3-position switch, and one variable capacitor. You don't have to get a perfect match, just within the range of the internal ATU, like 3:1. Once you find the right coil tap positions, the internal ATU should be able to handle the small mismatch with different antenna installations, etc. It may seem like a lot of trouble, but if you can match the EFHW, it's just about the most effective simple wire antenna you can use. 73, Scott K9MA -- Scott K9MA [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: PAR/LNR EFHW antenna
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In reply to this post by K9MA
the End Fed Half Wave Antennas group on Facebook,
started by N4LQ, Steve Ellington, promotes the use of a 49:1 transformer Steve does have a couple of videos on Youtube where he shows you him making one of these transformers check out how to build one, image is on Elgin Amateur Radio Society's website <https://elginradio.files.wordpress.com/2017/10/49-1-unun.jpg"> List of vendors of these if you do not want to build your own 49:1 Transformer Vendors ------------------------------------- myantennas http://myantennas.com/wp/ hyendcompany https://www.hyendcompany.nl/ balundesigns http://www.balundesigns.com/ MFJ MFJ-1982LP/MP/HP, MFJ-1984LP/MP/HP http://www.mfjenterprises.com/ packtenna (QRP only) http://packtenna.com/ communicationworld https://www.communicationworld.nl/antennes_end_fed_zelfbouw 2017.10.12 Al VE3GAM al ve3gam -------------------------------------------------- From: "K9MA" <[hidden email]> Sent: Monday, January 08, 2018 8:39 PM To: <[hidden email]> Subject: Re: [Elecraft] PAR/LNR EFHW antenna > On 1/8/2018 16:59, Rich Arland wrote: >> Failing that path, has anyone hooked an EFHW to the internal ATU with >> good results? I would also include a cut to frequency ground radial that >> I would lay out below the antenna. That would be the easiest thing and >> simple to employ. > > That definitely will not work: The impedance of the EFHW is much to high > for any internal ATU to match. The 64:1 balun may work, though I haven't > tried one. QRPKITS has a QRP tuner, but it works only on a single band. > Most any of the external antenna tuners will work, though they may be > lossy. > > The best solution, I think, is to build your own L-network tuner. One > coil, a 3-position switch, and one variable capacitor. You don't have to > get a perfect match, just within the range of the internal ATU, like 3:1. > Once you find the right coil tap positions, the internal ATU should be > able to handle the small mismatch with different antenna installations, > etc. > > It may seem like a lot of trouble, but if you can match the EFHW, it's > just about the most effective simple wire antenna you can use. > > 73, > > Scott K9MA > > -- > Scott K9MA > > [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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I would be cautious about using a transformer above 40 meters, as the
stray capacitance may be too large. I haven't tried it, though, so it might work with some transformers. 73, Scott K9MA On 1/8/2018 20:22, VE3GAM wrote: > the End Fed Half Wave Antennas group on Facebook, > started by N4LQ, Steve Ellington, > promotes the use of a 49:1 transformer > > Steve does have a couple of videos on Youtube where > he shows you him making one of these transformers > > check out how to build one, > image is on Elgin Amateur Radio Society's website > <https://elginradio.files.wordpress.com/2017/10/49-1-unun.jpg"> > > List of vendors of these if you do not want to build your own > > > 49:1 Transformer Vendors > ------------------------------------- > > myantennas > http://myantennas.com/wp/ > > hyendcompany > https://www.hyendcompany.nl/ > > balundesigns > http://www.balundesigns.com/ > > MFJ > MFJ-1982LP/MP/HP, MFJ-1984LP/MP/HP > http://www.mfjenterprises.com/ > > packtenna (QRP only) > http://packtenna.com/ > > communicationworld > https://www.communicationworld.nl/antennes_end_fed_zelfbouw > > > 2017.10.12 Al VE3GAM > > al ve3gam > > > > -------------------------------------------------- > From: "K9MA" <[hidden email]> > Sent: Monday, January 08, 2018 8:39 PM > To: <[hidden email]> > Subject: Re: [Elecraft] PAR/LNR EFHW antenna > >> On 1/8/2018 16:59, Rich Arland wrote: >>> Failing that path, has anyone hooked an EFHW to the internal ATU >>> with good results? I would also include a cut to frequency ground >>> radial that I would lay out below the antenna. That would be the >>> easiest thing and simple to employ. >> >> That definitely will not work: The impedance of the EFHW is much to >> high for any internal ATU to match. The 64:1 balun may work, though >> I haven't tried one. QRPKITS has a QRP tuner, but it works only on a >> single band. Most any of the external antenna tuners will work, >> though they may be lossy. >> >> The best solution, I think, is to build your own L-network tuner. >> One coil, a 3-position switch, and one variable capacitor. You don't >> have to get a perfect match, just within the range of the internal >> ATU, like 3:1. Once you find the right coil tap positions, the >> internal ATU should be able to handle the small mismatch with >> different antenna installations, etc. >> >> It may seem like a lot of trouble, but if you can match the EFHW, >> it's just about the most effective simple wire antenna you can use. >> >> 73, >> >> Scott K9MA >> >> -- >> Scott K9MA >> >> [hidden email] >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > -- Scott K9MA [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On 1/8/2018 8:19 PM, K9MA wrote:
> I would be cautious about using a transformer above 40 meters, as the > stray capacitance may be too large. I haven't tried it, though, so it > might work with some transformers. For years, we've been winding our transformers wrong. The windings should be on opposite sides of the core, so that capacitive coupling is minimized, NOT laying on top of one another. In a ferrite materialthat is SUITABLE for use as a transformer, the mu is high enough that a VERY high fraction of the flux in toroid is contained within the core, with very little leakage flux. Windings that lay on top of each other maximize capacitive coupling, and thus maximize common mode current. Windings on opposite sides of the core minimize common mode current. Ferrites are semiconductors, so they act as a dielectric. When we place windings on opposite sides of a core, we maximize magnetic coupling and minimize capacitive coupling, which is from one winding to the core and from the core to the other winding. That capacitance is VERY small if the windings are widely spaced. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Not only winding them wrong but if find more and more being used incorrectly. There is no one baling design that can be used in all applications. The more common error is the internal balun contained in tuners.
Bob, K4TAX Sent from my iPhone > On Jan 9, 2018, at 3:33 AM, Jim Brown <[hidden email]> wrote: > >> On 1/8/2018 8:19 PM, K9MA wrote: >> I would be cautious about using a transformer above 40 meters, as the stray capacitance may be too large. I haven't tried it, though, so it might work with some transformers. > > For years, we've been winding our transformers wrong. The windings should be on opposite sides of the core, so that capacitive coupling is minimized, NOT laying on top of one another. In a ferrite materialthat is SUITABLE for use as a transformer, the mu is high enough that a VERY high fraction of the flux in toroid is contained within the core, with very little leakage flux. Windings that lay on top of each other maximize capacitive coupling, and thus maximize common mode current. Windings on opposite sides of the core minimize common mode current. > > Ferrites are semiconductors, so they act as a dielectric. When we place windings on opposite sides of a core, we maximize magnetic coupling and minimize capacitive coupling, which is from one winding to the core and from the core to the other winding. That capacitance is VERY small if the windings are widely spaced. > > 73, Jim K9YC > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Darn autocorrect "balun"......not baling!
Bob, K4TAX Sent from my iPhone > On Jan 9, 2018, at 10:41 AM, Bob McGraw K4TAX <[hidden email]> wrote: > > Not only winding them wrong but if find more and more being used incorrectly. There is no one baling design that can be used in all applications. The more common error is the internal balun contained in tuners. > > Bob, K4TAX > > > Sent from my iPhone > >>> On Jan 9, 2018, at 3:33 AM, Jim Brown <[hidden email]> wrote: >>> >>> On 1/8/2018 8:19 PM, K9MA wrote: >>> I would be cautious about using a transformer above 40 meters, as the stray capacitance may be too large. I haven't tried it, though, so it might work with some transformers. >> >> For years, we've been winding our transformers wrong. The windings should be on opposite sides of the core, so that capacitive coupling is minimized, NOT laying on top of one another. In a ferrite materialthat is SUITABLE for use as a transformer, the mu is high enough that a VERY high fraction of the flux in toroid is contained within the core, with very little leakage flux. Windings that lay on top of each other maximize capacitive coupling, and thus maximize common mode current. Windings on opposite sides of the core minimize common mode current. >> >> Ferrites are semiconductors, so they act as a dielectric. When we place windings on opposite sides of a core, we maximize magnetic coupling and minimize capacitive coupling, which is from one winding to the core and from the core to the other winding. That capacitance is VERY small if the windings are widely spaced. >> >> 73, Jim K9YC >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On 1/9/2018 10:45, Bob McGraw K4TAX wrote:
> Darn autocorrect "balun"......not baling! Many, many years ago, I wrote a report on a balun I designed. The typist (remember those?) changed every "balun" to "balloon", and no doubt told all her friends how bad engineers are at spelling. 73, Scott K9MA -- Scott K9MA [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Jim Brown-10
I use an end-fed wire [1/2 wave on 80] from MyAntennas.com run along the
top of a wood fence about 1.8 meters high. It has a transformer in a sealed box. The outer surface of the coax seems to serve as the counterpoise. It enters the house through a steel pipe near the ground into a closet and thence to the K3/100. It works as good as one could expect on 80, 60, 40, 30, and 20. 40 seems to be it's sweet spot. It works on 160 ... not great ... but I make Q's. It's OK on 17 and 15, the SFI has prevented much testing on 12 and 10 although it has SWR minimums [1.3:1 or so] there. It has 1.2:1 SWR on 6 on which I have made exactly zero contacts when the band was open this last summer and could hear lots of stations. Apparently low SWR does not guarantee low loss, however any antenna is better than no antenna. [:-) I'd have to destroy it to see what's inside the box. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 1/9/2018 1:33 AM, Jim Brown wrote: > On 1/8/2018 8:19 PM, K9MA wrote: >> I would be cautious about using a transformer above 40 meters, as the >> stray capacitance may be too large. I haven't tried it, though, so >> it might work with some transformers. > > For years, we've been winding our transformers wrong. The windings > should be on opposite sides of the core, so that capacitive coupling > is minimized, NOT laying on top of one another. In a ferrite > materialthat is SUITABLE for use as a transformer, the mu is high > enough that a VERY high fraction of the flux in toroid is contained > within the core, with very little leakage flux. Windings that lay on > top of each other maximize capacitive coupling, and thus maximize > common mode current. Windings on opposite sides of the core minimize > common mode current. > > Ferrites are semiconductors, so they act as a dielectric. When we > place windings on opposite sides of a core, we maximize magnetic > coupling and minimize capacitive coupling, which is from one winding > to the core and from the core to the other winding. That capacitance > is VERY small if the windings are widely spaced. > > 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Inquiring minds want to know... :-)
Dennis NJ6G On 1/9/2018 13:25, Fred Jensen wrote: > I'd have to destroy it to see what's inside the box. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: PAR/LNR EFHW antenna
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He does sell just the box.
On 1/9/2018 1:28 PM, Dennis Moore wrote: > Inquiring minds want to know... :-) > > Dennis NJ6G > > > On 1/9/2018 13:25, Fred Jensen wrote: >> I'd have to destroy it to see what's inside the box. > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: PAR/LNR EFHW antenna
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In reply to this post by k6dgw
Going way back to the original post, it seems to me that there is a
simple answer: The OP wants something that is very portable, that the KX2 will tune. The whole balun discussion comes from trying to match a near-infinite impedance, and chopping the wire down a bit (or making it longer) is going to bring it to an impedance that the tuner can match. Lotta folks doing that. 73 -- Lynn ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: PAR/LNR EFHW antenna
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In reply to this post by Dennis Moore
here's a video from N4LQ Steve Ellington,
which shows the inside of the Myantennas box <https://www.youtube.com/watch?v=xfqlun3bdI0> Al ve3gam -------------------------------------------------- From: "Dennis Moore" <[hidden email]> Sent: Tuesday, January 09, 2018 4:28 PM To: <[hidden email]> Subject: Re: [Elecraft] PAR/LNR EFHW antenna > Inquiring minds want to know... :-) > > Dennis NJ6G > > > On 1/9/2018 13:25, Fred Jensen wrote: >> I'd have to destroy it to see what's inside the box. > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Lynn W. Taylor, WB6UUT-2
I use a switch tapped air inductor with a variable C on one end. It is an L network thus it is reversible and will match either Hi Z or Lo Z loads. This always brings the load to within range the ATU in the radio can resolve a match.
Bob, K4TAX Sent from my iPhone > On Jan 9, 2018, at 3:48 PM, Lynn W. Taylor, WB6UUT <[hidden email]> wrote: > > Going way back to the original post, it seems to me that there is a simple answer: > > The OP wants something that is very portable, that the KX2 will tune. > > The whole balun discussion comes from trying to match a near-infinite impedance, and chopping the wire down a bit (or making it longer) is going to bring it to an impedance that the tuner can match. > > Lotta folks doing that. > > 73 -- Lynn > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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