Re: [Elecraft] Miniature self-supporting HF antennas
(Consolidating replies to a couple of messages here...) The object of my exercise was not to measure the exact losses in the loading coil, nor to determine why it made such a poor antenna, but to determine which antenna would work best for the appropriate bands from a SOTA summit. The antennas under consideration were the loaded vertical (adjustable for all the bands required), a link-dipole (covering bands up to 15 metres), and various mono-band elevated ground plane verticals (one for each band from 20 metres to 10, though only 12 and 10 aren't covered by the dipole). I'd taken the loaded vertical on a couple of activations. One had been a reasonable activation (14 contacts on bands between 40 metres and 12 metres) and one had been a struggle (just 4 contacts, enough for the points, in over an hour and a half of calling on HF between 60 metres and 12 metres, with me resorting to CW for the last contact), but on both I'd noticed the reports I was being given were lower than I'd have expected. My friend could only help with the lower HF bands, so I have more confidence in those tests, and I wasn't expecting the loaded vertical to shine when compared to the dipole, but the magnitude of the difference was surprisingly wide. To give myself a baseline expectation I'd first tried contacting him with my (then) main 27ft tall vertical (which had some top-loading and a feed-point ATU), both with my main rig and the KX3 I planned to use to test the portable antennas. Somewhere I had detailed notes of all the numbers, but I can't find them. However, the QSOs are also in my log, and with the main rig at 100 watts we reported 5 and 9 both ways. With the KX3 at 10 watts we reported 5 and 7 both ways. I then took the KX3 outside to test the portable antennas, using it at the same 10 watt level. The best QSO on the loaded vertical has me giving him 5 and 1, and he giving me 3 and 1. On the dipole the log says 5 and 9 both ways. Some of that will be down to radiation pattern, height above ground, and so on, but it confirmed experience from the second summit mentioned above. Clearly, if I want to make contacts on the lower HF bands then the dipole is a far better bet. For the higher bands I had to rely on RBN and any contacts who happened to answer, so the comparison's a bit harder to quantify exactly. (RBN skimmers don't report every CQ, so you have to play games changing frequencies, and waiting, in order to get enough coverage.) However, as best I could figure, the loaded vertical was well down on the un-loaded mono-band ones as well as on the link dipole. Again, height above ground level will have had some effect. The loaded vertical has its own little tripod, so isn't far off the ground. The others all rely on telescopic fishing poles, so they're at least a few feet higher off the ground. In all cases the loaded vertical was worst, in some cases by a very large margin. At best (on 10 metres, which was clearly its best band) it was only 6dB or so so down on the elevated ground-plane vertical. That could be down to elevation, radials, the loading coil, or all three. I'd rather over-optimistically hoped that the self-supporting loaded vertical (total weight 1.5kgs) would do the SOTA job nicely. The dipole, a couple of verticals for the bands the dipole doesn't cover, pegs, guys, and a short (6 metre) telescopic pole weigh 2kgs in total. For SOTA purposes the loaded vertical was not worth carrying despite its (mostly) glowing reviews on eHam. Sure, I've made a few contacts with it from SOTA summits, so it wasn't totally useless, but the alternatives I now take are far better. Next time I'm tempted to make a link-dipole I'll make sure it has additional links for 10 and 12 metres so I can save myself the weight of the elevated ground-plane verticals I usually carry for those bands. On 21 Jul 2015 Wes N7WS wrote: If so, you are not determining the effects of loading coil loss On 21 Jul 2015 Mel, K6KBE wrote: does not tell you why one works better that the other one. -- 73, Rick, M0LEP (KX3 #3281) __ 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] Miniature self-supporting HF antennas
If you you are looking for a portable self-supporting antenna that is multi band and functions well, independent of terrain, it is really hard to beat a portable magnetic loop like the Alex Loop. I have used Magnetic Loops for at least the past 10 years (I have an MFJ and an Alex Loop and I have built a few homebrew ones for portable use) and I can say that the only real compromise when using a well built 1 meter diameter loop on 20m through 10m is bandwidth. Efficiency on the higher bands is good to excellent (usually ranging from about 30% up to about 90% on 10m). The efficiency does suffer when pushing a loop this small to cover 30m and 40m but it isn’t so bad as to make it impossible to make QSOs at the 5w to 10w level, even on SSB. The problem with 1/4 wave verticals (including loaded ones) is that they rely on radials / earth to complete the other half of the antenna and unless you want to spend a lot of time deploying radials (which I think defeats the whole purpose of this thread) then results are going to vary a lot depending on the soil conductivity. I think that most Hams would be quite surprised at how inefficient a short vertical with few radials really is, especially over rocky terrain. Using them near salt water is whole different story. Horizontal antennas require supports, so they are by definition not self-supporting. On most of the HF bands reasonable height is required to achieve any kind of half decent take-off angles for DX. Over poor soil you don’t have the efficiency issues you do with verticals. Moxon in his excellent book HF Antennas for all Locations”, suggests that if you are on a mountain/hill you can use the terrain to your advantage by mounting a low inverted-vee doublet, partway down the hill in the direction you want to work. This will significantly lower the take-off angle and can be quite effective for working DX in this sort of environment … but it still requires a support and this only works on a hill. So what does a well constructed 1 meter diameter Magnetic Loop give you : PROs - continuous coverage from 40m through 10m with a very close match to 50 ohms (SWR under 1.5:1 usually at resonance) on all bands - good efficiency from 20m through 10m and reduced, but usable, efficiency on 30m and 40m (assuming proper design and construction of the loop) - both high angle (useful for close-in NVIS contacts on 40m) and low angle radiation for DX on higher bands (note that the radiation pattern is a donut standing on its end) - no need for an antenna tuner (in fact it is not recommended; all tuning should be done by adjusting the capacitor on the loop) - at heights in excess of 1 radius (i.e. 1.5 feet from the bottom of the loop) very good ground independence, which makes tuning predictable regardless of terrain. - self contained, self supporting (with small tripod), compact and lightweight making it quite portable - directionality. A magnetic loop has bidirectional radiation pattern with lobes in the plane of the loop and a fairly deep null broadside - very quiet antenna on receive and from my experiences even a slight rotation of the loop can drastically reduce nearby electrical interference - 5 minute (or less) setup and takedown time - fairly low wind resistance (you will realize the importance of this if you have ever operated on the top of a mountain ! ) CONs - mediocre performance on 40m / 30m (for a 1 meter diameter loop) - narrow bandwidth (typically around 10 Khz 2:1 SWR bandwidth when tuned to resonance on a given band) This varies from band to band but you can expect a wider bandwidth on the higher bands and narrower bandwidth on the lower bands. This means that sitting on a frequency and calling CQ works great, while SP is a little more work as it requires frequent tweaking of the loop capacitor to resonate the antenna as there frequency changes - requires a means of either measuring SWR or Field Strength to adjust the tuning capacitor to resonate the loop for lowest SWR. - need to consider RF exposure and limit power to 5W to 10W for a manually tuned loop. Also the operator should not be closer than about 1 meter from the loop during TX at these power levels (I personally try to always sit broadside to the loop, no closer than arms length) - possible RF burn hazard. This is especially true for a home-brew loop with a bare radiator (i.e. copper or aluminum) and not as much of an issue for an antenna like the Alex Loop as the coax jacket provides protection. Observations - manual tuning works well with a little practice and often it is possible to achieve a 1:1 SWR just tuning by ear and peaking band noise. - for SP, moving off frequency a few KHz from the desired station and quick re-tweaking is pretty quick, but doesn’t work with a heavily occupied band (think Field Day on 20m) unless you want to be rude and TX over someone else (not recommended). - I can’t stress the importance of proper
Re: [Elecraft] Miniature self-supporting HF antennas
I look at DXscape from time-to-time but I'm still primarily a tuner and listener and I don't have some cluster tuning my radio for me. I have no quarrel with those who do, it's just not my cup of tea. Wes N7WS On 7/21/2015 9:08 PM, Dr. William J. Schmidt, II wrote: That just ain't right. You need to watch the spots! Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch - K9ZC Staunton, Illinois Owner - Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email: b...@wjschmidt.com -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wes (N7WS) Sent: Tuesday, July 21, 2015 11:02 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Miniature self-supporting HF antennas I was going to say something similar. Funny thing is though, although I'm a pretty active DXer, I've only worked J68HZ once. Three years ago on 20M RTTY. __ 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] Miniature self-supporting HF antennas
That just ain't right. You need to watch the spots! Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch - K9ZC Staunton, Illinois Owner - Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email: b...@wjschmidt.com -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wes (N7WS) Sent: Tuesday, July 21, 2015 11:02 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Miniature self-supporting HF antennas I was going to say something similar. Funny thing is though, although I'm a pretty active DXer, I've only worked J68HZ once. Three years ago on 20M RTTY. On 7/21/2015 5:54 PM, David Gilbert wrote: As they say, your callsign alone is probably worth 20db. ;) Dave AB7E On 7/21/2015 5:24 PM, Dr. William J. Schmidt, II wrote: I use a Superantennas YP3 with my own modeled tunings and some refinements (new set of coils and full sized elements on 12 meters too). 30-160 I just use dipoles. rolls of wire pre-cut with dog-leash clips on the end that snap onto a balun and alligator clips on the balun wire leads for attachment to the antenna wire. So far with this set-up I've worked more than 140,000 contacts in the Caribbean, 172 countries, close to 8BWAS. and all with a radio (K3) I can tuck into my back-pack, and antennas I can carry in my luggage. Lots of you have worked me as J68HZ. over 100,000 of you! __ 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] Miniature self-supporting HF antennas
As they say, your callsign alone is probably worth 20db. ;) Dave AB7E On 7/21/2015 5:24 PM, Dr. William J. Schmidt, II wrote: I use a Superantennas YP3 with my own modeled tunings and some refinements (new set of coils and full sized elements on 12 meters too). 30-160 I just use dipoles. rolls of wire pre-cut with dog-leash clips on the end that snap onto a balun and alligator clips on the balun wire leads for attachment to the antenna wire. So far with this set-up I've worked more than 140,000 contacts in the Caribbean, 172 countries, close to 8BWAS. and all with a radio (K3) I can tuck into my back-pack, and antennas I can carry in my luggage. Lots of you have worked me as J68HZ. over 100,000 of you! Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch - K9ZC Staunton, Illinois Owner - Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: http://www.VillaGrandPiton.com www.VillaGrandPiton.com email: mailto:b...@wjschmidt.com 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 xda...@cis-broadband.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] Miniature self-supporting HF antennas
That is exactly what I did, with the help of a friend a reasonable distance away with a reasonable S-meter, repeated antenna swapping, and a little help from skimmers on the RBN for control. I'm pretty sure the difference is real. I'd rather carry a lightweight telescopic pole with the means to guy it, and use an inverted-V dipole than trust that loaded vertical to get me contacts. On Tue 21 Jul Wes (N7WS) wrote: In other words, take measurements of antenna one, remove it and replace it with antenna two and note the change. Any other comparison is uncontrolled and suspect. -- 73, Rick, M0LEP (KX3 #3281) __ 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] Miniature self-supporting HF antennas
Your deep suspicion is probably unjustified. Certainly, examples can be found of inefficient antennas which suffer some inefficiency because of the coils but generally, the inefficiency is due to the need for the coils in the first place. Any antenna satisfying what I perceive are Wayne's needs is going to be inefficient because it is small and operated in close proximity to Mother Earth. There is a good chance that conductor and ground losses swamp coil loss. If one is going to compare one antenna with loading coils to another without coils to determine efficiency then they they must be tested under the exact conditions. In other words, take measurements of antenna one, remove it and replace it with antenna two and note the change. Any other comparison is uncontrolled and suspect. Wes N7WS On 7/20/2015 2:46 AM, Rick M0LEP wrote: So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. __ 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] Miniature self-supporting HF antennas
I was going to say something similar. Funny thing is though, although I'm a pretty active DXer, I've only worked J68HZ once. Three years ago on 20M RTTY. On 7/21/2015 5:54 PM, David Gilbert wrote: As they say, your callsign alone is probably worth 20db. ;) Dave AB7E On 7/21/2015 5:24 PM, Dr. William J. Schmidt, II wrote: I use a Superantennas YP3 with my own modeled tunings and some refinements (new set of coils and full sized elements on 12 meters too). 30-160 I just use dipoles. rolls of wire pre-cut with dog-leash clips on the end that snap onto a balun and alligator clips on the balun wire leads for attachment to the antenna wire. So far with this set-up I've worked more than 140,000 contacts in the Caribbean, 172 countries, close to 8BWAS. and all with a radio (K3) I can tuck into my back-pack, and antennas I can carry in my luggage. Lots of you have worked me as J68HZ. over 100,000 of you! __ 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] Miniature self-supporting HF antennas
Sorry Rick, Please let me explain, doing a antenna substitution works only in the following situations. 1. Both antennas are designed to have patterns similar in the direction of the receiving station or.2. Both antennas have the same TOA to the receiving station or3. Both antennas had the same amount of delivered power to the antenna or And I could go on. The test you did is a nice comfort feeling one but does not tell you why one works better that the other one. IMHO Mel, K6KBE From: Rick M0LEP m0...@hewett.org To: elecraft@mailman.qth.net Sent: Tuesday, July 21, 2015 3:08 PM Subject: Re: [Elecraft] Miniature self-supporting HF antennas That is exactly what I did, with the help of a friend a reasonable distance away with a reasonable S-meter, repeated antenna swapping, and a little help from skimmers on the RBN for control. I'm pretty sure the difference is real. I'd rather carry a lightweight telescopic pole with the means to guy it, and use an inverted-V dipole than trust that loaded vertical to get me contacts. On Tue 21 Jul Wes (N7WS) wrote: In other words, take measurements of antenna one, remove it and replace it with antenna two and note the change. Any other comparison is uncontrolled and suspect. -- 73, Rick, M0LEP (KX3 #3281) __ 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] Miniature self-supporting HF antennas
Unless I misunderstand (always a possibility) you compared a coil-loaded vertical to a wire inverted vee. Is this correct? If so, you are not determining the effects of loading coil loss, you are determining that a vertical antenna is different from a (nominally) horizontal antenna. It takes no experimentation to know this. On 7/21/2015 3:08 PM, Rick M0LEP wrote: That is exactly what I did, with the help of a friend a reasonable distance away with a reasonable S-meter, repeated antenna swapping, and a little help from skimmers on the RBN for control. I'm pretty sure the difference is real. I'd rather carry a lightweight telescopic pole with the means to guy it, and use an inverted-V dipole than trust that loaded vertical to get me contacts. On Tue 21 Jul Wes (N7WS) wrote: In other words, take measurements of antenna one, remove it and replace it with antenna two and note the change. Any other comparison is uncontrolled and suspect. __ 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] Miniature self-supporting HF antennas
I never said anything about base loading. That's where most of the current is, and therefore the most opportune location to create loss. There's no current at the end (top), of course, so a loading coil does no good at all there ... somewhere in between is generally best. Dave AB7E On 7/20/2015 2:37 PM, Tony Estep wrote: On Mon, Jul 20, 2015 at 3:56 PM, David Gilbert xda...@cis-broadband.com wrote: ...properly built coils aren't nearly as bad as you say === True, but even with a high-Q coil a typical base-loaded antenna inevitably has low efficiency. This is the consequence of the fact that a loaded antenna has a very low radiation resistance, which magnifies the impact of all other system losses. ON4UN's excellent book Low-band DXing has a detailed analysis that can help you make the best choice of setup. Tony KT0NY __ 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 xda...@cis-broadband.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] Miniature self-supporting HF antennas
Yeah, that's a low Q coil on a short antenna ... it's not going to be very efficient. Dave AB7E On 7/20/2015 2:35 PM, Rick M0LEP wrote: The one I got bitten by was the one reviewed here: http://www.eham.net/reviews/detail/1378 It isn't too bad for the top end of HF when most of the adjusting coil is not involved, but performance drops off dramatically once more than about a third of the adjustable coil is exposed. If you've got 100 watts (or more) to drive it with then I guess you might get somewhere with it, but with the KX3 it might as well have been a dummy load on 40 metres, never mind with the add-on coils for the lower end of HF. On Mon 20 Jul David Gilbert wrote: In general, properly built coils aren't nearly as bad as you say they are. It is possible to build coils with a Q of several hundred, and if you do the math you'll see that the resulting loss is essentially trivial. It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. __ 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] Miniature self-supporting HF antennas
Exactly, although of course a coil at the very top sees no current so doesn't do any good there unless there is some capacitive loading above it. Dave AB7E On 7/20/2015 2:44 PM, Jim Brown wrote: On Mon,7/20/2015 1:56 PM, David Gilbert wrote: It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. There was an excellent piece in QEX a year or two ago devoted to the design of short loaded antennas. It was published in two parts -- one dealt with measurement, the other with studying the effect of the position of the loading coil. The executive summary -- the part of the antenna carrying the greatest current does the most radiating, and for most short antennas, that's the part of the antenna closest to the feedpoint. The current distribution depends on the electrical length, including that coil. A loading coil near the feedpoint seriously degrades the radiation efficiency of the antenna, because the current maxima is in the coil, but the coil doesn't radiate! SO -- loading should be as far as possible from the feedpoint! All of this was borne out by the measurments. 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 xda...@cis-broadband.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] Miniature self-supporting HF antennas
My practical experience is that miniature antennas do not work very well. You end up with a miniature signal which is not much use with QRP. I recently operated from Vanuatu as YJ0BJ and I used a Steppir CrankIR vertical for 10 - 40m. It worked very well indeed and whilst it does not assemble in two minutes, it does all pack away in the carry bag provided. However, you need a mounting post, fence post or something to mount it on. My holiday location was almost on the beach so arguably I had the salt water benefit. However, I have tried it here at home, now with the 80m extender kit (still all packs in the one bag) and it works OK. I will be on again from YJ0BJ in November 10 - 80m. The rig will again be my K3. See the photos and write up on my YJ0BJ QRZ page. Barry VK2BJ On 20 July 2015 at 15:31, Jim Brown j...@audiosystemsgroup.com wrote: On Sun,7/19/2015 9:52 PM, David Gilbert wrote: It's not going to radiate any lower than the horizon, and that kind of low angle is extremely useful for long distances. That can be appropriate even for QRP, although it might be more propagation dependent versus making some high angle short skip contacts. If I want to see how far I can work when backpacking, I'm going with a vertical unless the ground conductivity is just plain awful. The soil conductivity on most high mountaintops IS just plain awful. :) BUT -- there's nothing like having your antenna on a 3,000 ft tower, even if it is made of rock. When you get there, almost anything works, and anything decent works really well. W6GJB has a go-kit for his KX3 that includes a simple telescoping antenna that mounts to a tripod with a coax connector in the base, and a couple of wire radials that can be tossed into surrounding vegetation if there is any, or lay on the ground if there is not. Last summer as a site survey for FD, we set that up at Berryessa Peak (70 miles N of SF), and in about ten minutes, made three contest-style CW Qs to JA, SA, and the east coast of the US. Spiderbeam sells a 40ft (12M) telescoping fiberglass pole that weighs 7# and collapses to 3ft-10in. About $135 with shipping from TN). For about the same price, there's the DK9SQ 33 ft carbon fibre pole that collapses to 3.8 ft and weighs 2.2#. I used one of those with my K2 at my old Chicago club's annual QRP night in a local park. A photo is on my qrz.com page. I taped a #22 wire to it, wedged it between the seat and the top of the picnic bench (at roughly a 45 degree angle), and laid out two more wires as radials. Running 5W on 30M, I easily made a half dozen QSOs, including one that was a Caribbean station running a pileup. I agree that the Alex Loop, as well as home brew versions of it, can be a pretty decent backpacking antenna. W6GJB also has one of those. 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 vk...@optusnet.com.au __ 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] Miniature self-supporting HF antennas
On 19 Jul 2015, at 17:45, Wayne Burdick asked Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) How about a higher tech solution than a balloon or kite? With the rise of the ubiquitous miniature drone you could take aloft a wire, or even with a pair of them suspend a horizontal dipole. Then there is the possibility of having synchronised pairs of drones suspending a multi element Yagi, which can be rotated, height varied to suit desired desired take off angle, element lengths reeled in and out to change bands. patent pending 73 David Anderson GM4JJJ __ 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] Miniature self-supporting HF antennas
LOL. Well, with poor ground conductivity, they become worm cookers. ;) Dave AB7E On 7/19/2015 9:59 PM, Phil Wheeler wrote: Dave, Re It's not going to radiate any lower than the horizon... -- I'd swear, based on on-the-air results, that I've had a few antennas which achieved that dubious distinction :-) 73, Phil W7OX On 7/19/15 9:52 PM, David Gilbert wrote: It's not going to radiate any lower than the horizon, and that kind of low angle is extremely useful for long distances. That can be appropriate even for QRP, although it might be more propagation dependent versus making some high angle short skip contacts. If I want to see how far I can work when backpacking, I'm going with a vertical unless the ground conductivity is just plain awful. Dave AB7E On 7/19/2015 5:07 PM, Fred Jensen wrote: KT5X believes [and I don't disagree] that vertical ground planes on mountain tops tend to radiate downhill which isn't real useful. If you're above the timberline, you're probably on a mountain. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.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 xda...@cis-broadband.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] Miniature self-supporting HF antennas
So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. -- 73, Rick, M0LEP (KX3 #3281) __ 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] Miniature self-supporting HF antennas
__ 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] Miniature self-supporting HF antennas
Well, I never operated from uncomfortable locations like above the tree line, but my experience with portable antennas has been the same. Short loaded antennas are not as good as wires. I prefer a dipole that can be configured as a sloper, V, etc. I have a 33' collapsible fiberglass pole that has been useful where there aren't enough trees. It's not really suitable for backpacking, but smaller and lighter ones are available. 73, Vic, 4X6GP/K2VCO Rehovot, Israel http://www.qsl.net/k2vco/ On 20 Jul 2015 12:46, Rick M0LEP wrote: So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. __ 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] Miniature self-supporting HF antennas
I suggested this about two years ago as a DXpedition antenna for 160m. With the right drone, it could hold up enough wire to continuously power it, and with GPS it would automatically adjust for varying wind. It's not a backpacking antenna, though ... far too much weight. Dave AB7E On 7/20/2015 12:39 AM, David Anderson wrote: On 19 Jul 2015, at 17:45, Wayne Burdick asked Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) How about a higher tech solution than a balloon or kite? With the rise of the ubiquitous miniature drone you could take aloft a wire, or even with a pair of them suspend a horizontal dipole. Then there is the possibility of having synchronised pairs of drones suspending a multi element Yagi, which can be rotated, height varied to suit desired desired take off angle, element lengths reeled in and out to change bands. patent pending 73 David Anderson GM4JJJ __ 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 xda...@cis-broadband.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] Miniature self-supporting HF antennas
Yes, I too prefer to get wire in the sky, and an inverted-V dipole works pretty well. I have one with link breaks in it so that it can quickly be changed for different bands (using 2mm or 3mm radio-control power connectors for the breaks because they're very small, light, and make a good connection), and a couple of fibreglass telescopic flag-poles. One collapses to about 18 inches so fits in a back-pack easily enough, and extends to 18 feet. The other (which only goes on shorter walks) is about 28 foot long when extended, and about 3 foot 6 inches when collapsed. That set-up, however, doesn't fit Wayne's breaks down to 8 inches ideal. On Mon 20 Jul Vic Rosenthal wrote: I prefer a dipole that can be configured as a sloper, V, etc. I have a 33' collapsible fiberglass pole that has been useful where there aren't enough trees. It's not really suitable for backpacking, but smaller and lighter ones are available. -- 73, Rick, M0LEP (KX3 #3281) Simony's eyes gleamed with the gleam of a man who had seen the future and found it covered with armour plating. -- (Terry Pratchett, Small Gods) __ 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] Miniature self-supporting HF antennas
One of the better sources of information and portable antennas is found at http://www.dj0ip.de/antennas/ http://www.dj0ip.de/antennas/ Rick has some extensive test results on baluns and portable antennas on his website. His OFCD antenna is an ideal back packing antenna covering most all bands with a very reasonable tuner. 73 Bob, K4TAX On 7/19/2015 9:51 PM, Tony Estep wrote: On Sun, Jul 19, 2015 at 9:12 PM, Don Wilhelm w3...@embarqmail.com wrote: Richard, Two properly spaced and phased radiators = I have a terrific wire-beam antenna that rolls up into a package that weighs only a couple of pounds. However, it requires one rope into a tree or other type of sky-hook. It is good for 20, 17, 15, 12 and 10 and is bi-directional. It's a form of W8JK, but is fed at the end and has series capacitors in each radiator to make it work over a 2:1 frequency range. I designed it with EZNEC and I'll send the model to anybody who wants it. It's fed with window line and requires a balun at the transmitter. It takes a good tuner to match it, but the Elecraft tuners can do the job. Anyway, it doesn't meet Wayne's request for a free-standing antenna, but it's a cool field-day antenna, especially here in the middle of the country where a bi-directional antenna is a good thing. Tony KT0NY __ 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 rmcg...@blomand.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] Miniature self-supporting HF antennas
My favorite all around travelling/hiking KX3 antenna is a 20 mtr endfed half wave (EFHW) wire fed with an electrical quarter wave of TV twinlead. See http://w0vlz.blogspot.com/2012/06/another-portable-antenna.html With the KX3/KXAT3 it will load up on 40, 30, 20, 17 and 10. My 20 meter zepp is light weight and it only needs one support, especially when deployed as an inverted V. I've made use a large bush for a support before but usaully I'm familiar enough with the location that I know whether I'll find a tree or not. If not, I carry along a 16' crappie pole (cheap, light and collapses to less than 4') and some extra nylon cord for guy lines. Niel - W0VLZ Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? snip But the search for the ideal miniature HF antenna continues: something both very compact*and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. snip 73, 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] Miniature self-supporting HF antennas
On Mon,7/20/2015 7:34 AM, Niel Wiegand wrote: My favorite all around travelling/hiking KX3 antenna is a 20 mtr endfed half wave (EFHW) wire fed with an electrical quarter wave of TV twinlead. See http://w0vlz.blogspot.com/2012/06/another-portable-antenna.html With the KX3/KXAT3 it will load up on 40, 30, 20, 17 and 10. Here's another way to do it. http://k9yc.com/VerticalDipole.pdf All you need is some wire, some coax, that PL259 adapter, and a clamp-on ferrite core. Adjust the length of wire and the distance between the wire and the ferrite choke so that each are a quarter-wave. This antenna can be rigged horizontally, vertically, or sloping, depending on the available skyhooks. 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] Miniature self-supporting HF antennas
The one I got bitten by was the one reviewed here: http://www.eham.net/reviews/detail/1378 It isn't too bad for the top end of HF when most of the adjusting coil is not involved, but performance drops off dramatically once more than about a third of the adjustable coil is exposed. If you've got 100 watts (or more) to drive it with then I guess you might get somewhere with it, but with the KX3 it might as well have been a dummy load on 40 metres, never mind with the add-on coils for the lower end of HF. On Mon 20 Jul David Gilbert wrote: In general, properly built coils aren't nearly as bad as you say they are. It is possible to build coils with a Q of several hundred, and if you do the math you'll see that the resulting loss is essentially trivial. It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. -- 73, Rick, M0LEP (KX3 #3281) __ 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] Miniature self-supporting HF antennas
Terrible spelling, Buddipole, Sorry. Mel, K6KBE From: Mel Farrer farrerfo...@yahoo.com To: David Gilbert xda...@cis-broadband.com; elecraft@mailman.qth.net elecraft@mailman.qth.net Sent: Monday, July 20, 2015 2:38 PM Subject: Re: [Elecraft] Miniature self-supporting HF antennas A good example is the Biddipole concept. Mel, K6KBE From: David Gilbert xda...@cis-broadband.com To: elecraft@mailman.qth.net Sent: Monday, July 20, 2015 1:56 PM Subject: Re: [Elecraft] Miniature self-supporting HF antennas In general, properly built coils aren't nearly as bad as you say they are. It is possible to build coils with a Q of several hundred, and if you do the math you'll see that the resulting loss is essentially trivial. It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. Dave AB7E On 7/20/2015 2:46 AM, Rick M0LEP wrote: So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. __ 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] Miniature self-supporting HF antennas
On Mon, Jul 20, 2015 at 3:56 PM, David Gilbert xda...@cis-broadband.com wrote: ...properly built coils aren't nearly as bad as you say === True, but even with a high-Q coil a typical base-loaded antenna inevitably has low efficiency. This is the consequence of the fact that a loaded antenna has a very low radiation resistance, which magnifies the impact of all other system losses. ON4UN's excellent book Low-band DXing has a detailed analysis that can help you make the best choice of setup. Tony KT0NY __ 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] Miniature self-supporting HF antennas
A good example is the Biddipole concept. Mel, K6KBE From: David Gilbert xda...@cis-broadband.com To: elecraft@mailman.qth.net Sent: Monday, July 20, 2015 1:56 PM Subject: Re: [Elecraft] Miniature self-supporting HF antennas In general, properly built coils aren't nearly as bad as you say they are. It is possible to build coils with a Q of several hundred, and if you do the math you'll see that the resulting loss is essentially trivial. It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. Dave AB7E On 7/20/2015 2:46 AM, Rick M0LEP wrote: So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. __ 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] Miniature self-supporting HF antennas
On Mon,7/20/2015 1:56 PM, David Gilbert wrote: It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. There was an excellent piece in QEX a year or two ago devoted to the design of short loaded antennas. It was published in two parts -- one dealt with measurement, the other with studying the effect of the position of the loading coil. The executive summary -- the part of the antenna carrying the greatest current does the most radiating, and for most short antennas, that's the part of the antenna closest to the feedpoint. The current distribution depends on the electrical length, including that coil. A loading coil near the feedpoint seriously degrades the radiation efficiency of the antenna, because the current maxima is in the coil, but the coil doesn't radiate! SO -- loading should be as far as possible from the feedpoint! All of this was borne out by the measurments. 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] Miniature self-supporting HF antennas
In general, properly built coils aren't nearly as bad as you say they are. It is possible to build coils with a Q of several hundred, and if you do the math you'll see that the resulting loss is essentially trivial. It all depends on the rest of the antenna, and yes, a very short antenna with a crummy coil in the wrong place is going to suck. But some of the best antennas on the market right now use coil loading very effectively. Dave AB7E On 7/20/2015 2:46 AM, Rick M0LEP wrote: So far, I've found nothing that comes close, and there's nothing more frustrating than getting to the top and then finding the antenna you have is doing a poor job. I now regard anything which relies on loading coils with deep suspicion. That coil's usually doing a fine job of converting RF to heat. One such antenna I tested against an inverted-V dipole turned out to be over 20dB down on the dipole for 40 metres. On Sun 19 Jul Wayne Burdick wrote: But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. __ 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] Miniature self-supporting HF antennas
Small dimension and weight dictate thin wires, say gauge 26-28. A magnetic loop is relatively heavy for portable QRP. Verticals made of piece of wire are great over salt water or when conditions are great. For support I use 25ft pole collapsible to 2 ft. Away from the sea, two long wires made of thin wire are best IMHO. Or one long wire with a shorter wire. I understand that hanging a long wire is harder than shooting a vertical. When in VK I had 2 70 ft long wires just 20ft high, plus a 30ft vertical plus a couple of radials. This was far from water on a flat land. I could make an antenna from any combination of long wires, a radial or a vertical. Nearly always the best antenna was 2 long wires connected directly to a tuner, and very rarely one long wire with a vertical. In no case was the vertical with radials best. The reason a long wire is better than a vertical (most of the time) is lower losses and more radiation at many angles. So a greater chance of success somewhere. Ignacy, NO9E -- View this message in context: http://elecraft.365791.n2.nabble.com/Miniature-self-supporting-HF-antennas-tp7605064p7605176.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Miniature self-supporting HF antennas
I use two different portable antennas, One is the super antennas yp3 3 element antenna and the other is the TW 2010 antenna. If i'm going to be portable for a while Ill put the 3 element antenna up. Its pretty fiddly and changing bands is a pain. Its one band at a time. The performance is very good and it really lightweight and small to pack.The TW antenna works great and takes 5 minutes to set up. In a nutshell it's a DX antenna. Distant stations are worked with amazing frequency for such a small antenna. Its my favorite portable. Its actually larger to pack than the 3 element without the mast. However, that fades when its quickly set up and working. Like any antenna, keep them away from noise sources and in the clear and the results will be good. George NE2I On Sunday, July 19, 2015 7:21 PM, Fred Jensen k6...@foothill.net wrote: Usefulness of any 10 meter antenna is declining. :-) FWIW: My Buddipole weighed 17 lbs, and I sold it and used the proceeds to get an AlexLoop. It weighs about 1.6 lbs, less if I take it out of the neat canvas case, 2 lbs with the lightweight tripod. I like it a lot. I can set it up in less than 5 min, it is pretty much immune to anyone's definition of ground, and it works very well. Touchy to tune on 40, not so bad on 30 and easy on 20 and the rest. Very narrow BW, I sit under it so I can reach up and tune it using the K2 SWR indication. It's pricey, but you can make one yourself for about 1/10th the cost. Just remember, these guys are resonant transformers and MUST be at resonance so bypass the ATU. The EFHW is very popular with the SOTA crowd, extremely light, only needs one support. Mine works best with a 6 pigtail hanging off the shield of the BNC connector. They too seem to be fairly immune to ground, low current down where you are. My meager experience is that any antenna you can make resonant will probably perform a little better than a random wire, but I've made a lot of KX1 Q's with a 26 ft wire and counterpoise made from a piece of RG-58. KT5X believes [and I don't disagree] that vertical ground planes on mountain tops tend to radiate downhill which isn't real useful. If you're above the timberline, you're probably on a mountain. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.org On 7/19/2015 9:45 AM, Wayne Burdick wrote: Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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 n...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help:
Re: [Elecraft] Miniature self-supporting HF antennas
On Sun, Jul 19, 2015 at 9:12 PM, Don Wilhelm w3...@embarqmail.com wrote: Richard, Two properly spaced and phased radiators = I have a terrific wire-beam antenna that rolls up into a package that weighs only a couple of pounds. However, it requires one rope into a tree or other type of sky-hook. It is good for 20, 17, 15, 12 and 10 and is bi-directional. It's a form of W8JK, but is fed at the end and has series capacitors in each radiator to make it work over a 2:1 frequency range. I designed it with EZNEC and I'll send the model to anybody who wants it. It's fed with window line and requires a balun at the transmitter. It takes a good tuner to match it, but the Elecraft tuners can do the job. Anyway, it doesn't meet Wayne's request for a free-standing antenna, but it's a cool field-day antenna, especially here in the middle of the country where a bi-directional antenna is a good thing. Tony KT0NY __ 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] Miniature self-supporting HF antennas
Used to be a fellow that owned and operated motel in a small town in Ne. He was in a fringe area for tv.. and didn't want to have the guests bothered with anything more than just the fringe (noise and snow) reception on all but one tv channnel. SO.. his ham antenna was alternatively the 2nd story window screen (metal), and the bed springs, on the second floor. Yes.. they worked better with a good ground. He didn't contest, so it was a manual tuner. And it worked right nice. No one knew... but the fellows he talked to.. and after 6 - 8 months of chatter.. he might let you know what his antenna was. Neat guy! Nifty antenna! Have a great day, --... ...-- Dale - WC7S in Wy __ 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] Miniature self-supporting HF antennas
Usefulness of any 10 meter antenna is declining. :-) FWIW: My Buddipole weighed 17 lbs, and I sold it and used the proceeds to get an AlexLoop. It weighs about 1.6 lbs, less if I take it out of the neat canvas case, 2 lbs with the lightweight tripod. I like it a lot. I can set it up in less than 5 min, it is pretty much immune to anyone's definition of ground, and it works very well. Touchy to tune on 40, not so bad on 30 and easy on 20 and the rest. Very narrow BW, I sit under it so I can reach up and tune it using the K2 SWR indication. It's pricey, but you can make one yourself for about 1/10th the cost. Just remember, these guys are resonant transformers and MUST be at resonance so bypass the ATU. The EFHW is very popular with the SOTA crowd, extremely light, only needs one support. Mine works best with a 6 pigtail hanging off the shield of the BNC connector. They too seem to be fairly immune to ground, low current down where you are. My meager experience is that any antenna you can make resonant will probably perform a little better than a random wire, but I've made a lot of KX1 Q's with a 26 ft wire and counterpoise made from a piece of RG-58. KT5X believes [and I don't disagree] that vertical ground planes on mountain tops tend to radiate downhill which isn't real useful. If you're above the timberline, you're probably on a mountain. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.org On 7/19/2015 9:45 AM, Wayne Burdick wrote: Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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] Miniature self-supporting HF antennas
Richard, Two properly spaced and phased radiators are all that is necessary for a 2 element beam - two Alexloops, 2 verticals, two dipoles, etc. While setup in 2 minutes may not be practical at 20 meters, it is practical at 2 meters, and you may even devise something that looks like an umbrella. Think of the Hex Beam - 2 elements that sort of look like an inverted umbrella. 73, Don W3FPR On 7/19/2015 9:43 PM, Richard Donner wrote: I guess I would like a 20 meter 2 elment beam that sets up in 2 minutes and weighs two pounds. If it could pop open and shut like an umbrella that would work for me. Any ideas. Richard __ 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] Miniature self-supporting HF antennas
I recently used a 20m EFHW to operate from 12,300' Trail Ridge (SOTA W0C/FR-123) on June 28. I wanted a very quick activation due to thunderstorm concerns so I took a 15' mast (collapsible to ~18 inches), mounted it to a cairn of stones with a bungee and attached the far end to a stone. I made 6 contacts in 6 minutes and then beat a hasty retreat down the summit. About an hour earlier and 60 miles south of me several hikers were struck by lightning as they descended Mt. Bierstadt (see below). http://www.examiner.com/article/lightning-safety-tips-for-mountain-travel Fast and simple is my rule when operating above timberline in the summer! 73, Bill W4ZV -- View this message in context: http://elecraft.365791.n2.nabble.com/Miniature-self-supporting-HF-antennas-tp7605064p7605079.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Miniature self-supporting HF antennas
My two cents worth. My favorite antenna for SOTA turns out to be the 20 meter Endfedz followed by the Alex Loop. I have done a receive comparison between the Alex loop , Endfedz and a full size 20 meter vertical with radials. In this sketchy little test the Verical came out best followed very closely by the other two antennas. It was amazing to see how well the 3 foot diameter loop performed. I guess I would like a 20 meter 2 elment beam that sets up in 2 minutes and weighs two pounds. If it could pop open and shut like an umbrella that would work for me. Any ideas. Richard __ 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] Miniature self-supporting HF antennas
My favorite is the bush sloper. To launch it, I use an E-Z Hang (slingshot / fishing reel). The scrub on SoCal mountains is usable to support an end-fed wire, facing downhill. I recommend a counterpoise facing uphill. The end-fed can be 50 to 200 feet long (145 feet seems best all-around match using the ATU). I use a throway fishing weight to be the E-Z Hang projectile, tugging the #24 wire along until it bashes into a plant or the ground. The weight is attached to the wire via a short piece of thin monofilament, so it can break away without stretching the wire. I attach the radiator and counterpoise directly to the KX3 via a BNC - Banana adapter. When done, I just spool up the #24, usually losing the fishing weight in the process. If it's a multiple hilltop day, I have half a dozen of these in my pack. Being a sloper, it has some forward gain but a fairly high angle because of proximity to the ground. SoCal mountain ground is a rather vague concept though and I've made a few dozen DX contacts running 2-3W, CW. I have WAS done this way, minus RI and VT. I've had some luck using a tilt up telescoping aluminum 33 foot vertical on 40 and 15m, but the dern thing is unwieldy and heavy to pack around, and at 5.5 feet long (collapsed) only fits on my large hunting pack. I'd sure like to see a portable multi-band vertical that's easier to lug around than this, maybe one that collapses to less than four feet and weighs less than three pounds. The 33 footer weighs almost ten pounds I've stopped punishing myself, and don't use it much any more. No fish stories today, sorry. 73, matt W6NIA On Sun, 19 Jul 2015 09:45:47 -0700, you wrote: Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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 mzil...@roadrunner.com Matt Zilmer, W6NIA -- Always store beer in a dark place. -R. Heinlein __ 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] Miniature self-supporting HF antennas
Wayne, From time to time, my radio club collars me to do a program at one of our meetings. I usually lecture on antennas targeting the new ham. There are two points I try to leave the crowd with: 1. There is no such thing as the perfect antenna. Each is a compromise of some sort. 2. No ham has too many antennas. Efficiency, size, effectiveness, cost, and bandwidth are all inter-connected. I wish you great success in your quest. I'll be watching as I too would like to discover the perfect antenna. Having said this, have you tried a vertical dipole fed with open wire or ladder line? You gain by having a low angle antenna with low transmission line loss, and it requires only one support. 73, Barry K3NDM - Original Message - From: Wayne Burdick n...@elecraft.com To: elecraft elecraft@mailman.qth.net Cc: KX3 k...@yahoogroups.com Sent: Sunday, July 19, 2015 12:45:47 PM Subject: [Elecraft] Miniature self-supporting HF antennas Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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 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] Miniature self-supporting HF antennas
I’m interested in where this one’s going. Restrictions on my living accommodations relegate me to an indoor wire. I managed to work coast to coast with the KX3 and JT65 using its internal tuner. I’d like more ideas. dale W5OHM On Jul 19, 2015, at 11:45 AM, Wayne Burdick n...@elecraft.com wrote: Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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 dled...@camtel.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] Miniature self-supporting HF antennas
I am not an antenna purist and will use whatever is handy but my favourite antenna (at the moment) are a 44 foot Center feed zepp with tv twinlead and a 4:1 balun or if trees are not available I really like my semi homebrew center loaded vertical using a 12 inch base rod, a Wolf River Silver Bullet coil and a collapsible military whip for 80/40 or just a 36 inch whip for 20 - 10 if I want to be stealthy. I had a buddy stick but it is to finicky to tune, whereas the Wolf river coil just slides down for maximum noise and let the KX3/KXPA take the last bit of swr out. For radials you can't beat the tape measure radials. On Sun, Jul 19, 2015 at 12:45 PM, Wayne Burdick n...@elecraft.com wrote: Hi all, Have you found the perfect above-the-treeline backpacking antenna for use with your KX3 or other small rig? I've used everything from a 10-meter coat hanger whip, to a yagi that breaks down into two dozen pieces, to a dipole held up at the center by a willing (and tall) campmate. The variety (and price range) of such antennas is staggering. I've had pretty amazing results using short, base-loaded antennas on the higher bands--especially when conditions were good. My personal best is JA from W6 on 15-meter SSB, running 3 watts to a Maldol 48 whip. These antennas collapse and break down into just two pieces, taking very little space in my lightweight go-bag. This leaves room for a couple of 25' wires, adapters, and weights for times when there are trees available. But the search for the ideal miniature HF antenna continues: something both very compact *and* highly efficient. Ideally it would break down to a length of 8 or less, do an excellent job on 20 meters and up, and earn a passing grade on 30 and/or 40 meters. One other key factor, at least with the KX3/KX1/K1 genre, is to take maximal advantage of the rig's internal ATU. A wide-range ATU (such as the KXAT3) can turn a narrow-banded antenna into one that covers a full band or even multiple bands, within limits. One general approach is to coarse-tune the antenna's own inductance, then let the ATU do cleanup. Is the best antenna for backpacking a very small magnetic loop? A cleverly designed, center-loaded telescoping whip? A length of #30 wire lofted by a small helium balloon? (Or, more intriguingly, some combination of these?) I'd be interested in hearing about your antenna theories and field experiences, backed up by entertaining fish stories, if they aren't embellished to an embarrassing degree. If your supporting documentation is too voluminous for the forum (attached photos, etc.), feel free to email me directly. If anything substantive or surprising emerges, I'll do a followup posting. 73, 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 bill.va...@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] Miniature self-supporting HF antennas
Dave, Re It's not going to radiate any lower than the horizon... -- I'd swear, based on on-the-air results, that I've had a few antennas which achieved that dubious distinction :-) 73, Phil W7OX On 7/19/15 9:52 PM, David Gilbert wrote: It's not going to radiate any lower than the horizon, and that kind of low angle is extremely useful for long distances. That can be appropriate even for QRP, although it might be more propagation dependent versus making some high angle short skip contacts. If I want to see how far I can work when backpacking, I'm going with a vertical unless the ground conductivity is just plain awful. Dave AB7E On 7/19/2015 5:07 PM, Fred Jensen wrote: KT5X believes [and I don't disagree] that vertical ground planes on mountain tops tend to radiate downhill which isn't real useful. If you're above the timberline, you're probably on a mountain. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.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] Miniature self-supporting HF antennas
On Sun,7/19/2015 9:52 PM, David Gilbert wrote: It's not going to radiate any lower than the horizon, and that kind of low angle is extremely useful for long distances. That can be appropriate even for QRP, although it might be more propagation dependent versus making some high angle short skip contacts. If I want to see how far I can work when backpacking, I'm going with a vertical unless the ground conductivity is just plain awful. The soil conductivity on most high mountaintops IS just plain awful. :) BUT -- there's nothing like having your antenna on a 3,000 ft tower, even if it is made of rock. When you get there, almost anything works, and anything decent works really well. W6GJB has a go-kit for his KX3 that includes a simple telescoping antenna that mounts to a tripod with a coax connector in the base, and a couple of wire radials that can be tossed into surrounding vegetation if there is any, or lay on the ground if there is not. Last summer as a site survey for FD, we set that up at Berryessa Peak (70 miles N of SF), and in about ten minutes, made three contest-style CW Qs to JA, SA, and the east coast of the US. Spiderbeam sells a 40ft (12M) telescoping fiberglass pole that weighs 7# and collapses to 3ft-10in. About $135 with shipping from TN). For about the same price, there's the DK9SQ 33 ft carbon fibre pole that collapses to 3.8 ft and weighs 2.2#. I used one of those with my K2 at my old Chicago club's annual QRP night in a local park. A photo is on my qrz.com page. I taped a #22 wire to it, wedged it between the seat and the top of the picnic bench (at roughly a 45 degree angle), and laid out two more wires as radials. Running 5W on 30M, I easily made a half dozen QSOs, including one that was a Caribbean station running a pileup. I agree that the Alex Loop, as well as home brew versions of it, can be a pretty decent backpacking antenna. W6GJB also has one of those. 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] Miniature self-supporting HF antennas
It's not going to radiate any lower than the horizon, and that kind of low angle is extremely useful for long distances. That can be appropriate even for QRP, although it might be more propagation dependent versus making some high angle short skip contacts. If I want to see how far I can work when backpacking, I'm going with a vertical unless the ground conductivity is just plain awful. Dave AB7E On 7/19/2015 5:07 PM, Fred Jensen wrote: KT5X believes [and I don't disagree] that vertical ground planes on mountain tops tend to radiate downhill which isn't real useful. If you're above the timberline, you're probably on a mountain. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.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
