Re: [Elecraft] RF in the Trees
There is an excellent video magazine here, all about kite antennas in Great Britain http://www.txfilms.co.uk/txfactor/txf003.shtml 73 de David G4DMP In a recent message, K8JHR jricha...@k8jhr.com writes Short wave listeners use kites and baloons to hold up long wire antennas all the time. I did this long before becoming a ham. -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] RF in the Trees
Thanks very much for showing me HYpower Anntennas. They look very interesting, and I am going to call them with questions. Gerry Sent from my iPhone this time On Jun 26, 2014, at 9:39 AM, Walter Underwood wun...@wunderwood.org wrote: For pre-built antennas, HyPower is a good choice. He has lots of options, fan dipoles, loaded dipoles, even combinations. I have a fan dipole made from a full-size 40m element and an element that is full-size for 80 and loaded for 80. He also sells the loading coils if you would rather DIY. http://www.hypowerantenna.com/ wunder K6WRU On Jun 26, 2014, at 5:30 AM, Charlie T, K3ICH pin...@erols.com wrote: Don't rule out traps. Also, the RF Connection and probably others, sell a nice stranded copperweld wire that has a black polyethylene insulation. If I remember correctly, it is 13 ga and is ideal for antennas. For all practical purposes, it doesn't stretch, is fairly slippery and only a little springier than hard drawn copper. I use those double ferrule aluminum crimp on's that are designed for flexible wire cable to hold everything together. I was concerned about them holding through the poly insulation, but the following antenna has been up for about ten years now. It consists of a double (fan) dipole with a pair of 80 meter traps in the top leg for 160 80 M coverage and a pair of 40 meter traps in the lower leg for 60 40 M coverage. It is fed thru a 1:1 balun with RG-213 and is tuned for resonance. Basically, I operate SSB 99% of the time, so the antenna is tuned for that end of the bands. An MN-2700 tuner in the shack takes care of small excursions from resonance. It's only up about 50 feet, so performance is what you'd expect. It's not straight either and is sort of a lazy Z, being strung between two 55' telephone poles that are 105 feet apart. The ends droop down at about 45 degrees to tie-off points in trees. A compromise? Yes, but it works. 73, Charlie k3ICH - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 1:55 AM Subject: Re: [Elecraft] RF in the Trees On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander
Re: [Elecraft] RF in the Trees
I wonder if the tree hurts during key down? Sent from my iPhone this time On Jun 26, 2014, at 6:05 PM, Dauer, Edward eda...@law.du.edu wrote: Now THAT is what being a ham is about! OK, my part in this thread is over. Loading a tree can't be topped. Ted, KN1CBR We have one member of the ARRL Experimental Group on 600m that has actually loaded a pine tree to act as a vertical antenna, He wrapped a huge amount of wire around the base of the tree as a coupling coil. 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@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 gerrylear...@icloud.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] RF in the Trees
I seem to remember seeing some report about loading trees done for the military. I'll see if I can find it again. Cheers - Dave (G0DJA) - Original Message - From: Gerry leary gerrylear...@icloud.com To: Dauer, Edward eda...@law.du.edu Cc: elecraft@mailman.qth.net Sent: Friday, June 27, 2014 10:31 AM Subject: Re: [Elecraft] RF in the Trees I wonder if the tree hurts during key down? Sent from my iPhone this time On Jun 26, 2014, at 6:05 PM, Dauer, Edward eda...@law.du.edu wrote: Now THAT is what being a ham is about! OK, my part in this thread is over. Loading a tree can't be topped. Ted, KN1CBR __ 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] RF in the Trees
Heres the link to the experiments on 600M to load up trees as antennas and the page has links to the work done by the military, and other links to similar experiments. http://w5jgv.com/tree_antenna/index.htm Cheers - Dave (G0DJA) - Original Message - From: Gerry leary gerrylear...@icloud.com To: Dauer, Edward eda...@law.du.edu Cc: elecraft@mailman.qth.net Sent: Friday, June 27, 2014 10:31 AM Subject: Re: [Elecraft] RF in the Trees I wonder if the tree hurts during key down? Sent from my iPhone this time On Jun 26, 2014, at 6:05 PM, Dauer, Edward eda...@law.du.edu wrote: Now THAT is what being a ham is about! OK, my part in this thread is over. Loading a tree can't be topped. Ted, KN1CBR __ 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] RF in the Trees
I do it a little diffeerently. I tie a rock on the end of the Antenna that needs to be in the tree. Then I lay the wire untangled on the ground. Then I tie the other end to myself so I don't throw the wire where I can't find it. I can't get the heighth I would like, But I don't have to try to find the thrown end of the wire later. Sent from my iPhone this time On Jun 26, 2014, at 5:48 PM, Phil Hystad phys...@mac.com wrote: This may be off topic, but in light of it being Field Day Weekend in the US The problem with the bow or slingshot is when (if) the projectile comes down. The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. The slingshot can improve over the arrow by increasing mass but can be equally dangerous. Accurate shots are challenging. In my case, the arrows I shoot up into and over trees always land on my property and I am the only one on my property at the time. So, not much chance of hurting anyone. I don't think my bow has enough power to launch an arrow off of my property. Not that my property is that great, more that my bow is not that powerful (30 lb maximum pull). It is just good enough to launch up into and over my trees. I have never had an arrow get hung up in branches in all of my experience with the bow. I think maybe I am just lucky though. 73, phil, K7PEH __ 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 gerrylear...@icloud.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] RF in the Trees
The professional Arborists use a cloth or leather bag filled with lead shot and something called tangle-free line or similar to throw up in a tree so that they can pull up a supporting rope for tree trimming etc. From what I've seen, the bag is about the size of a tear drop shaped golf ball. The idea of the shot instead of a solid weight is to make the bag less damaging if it hits your house (or window) on the way down. I have a neighbor who's son is an arborist, so I've watched him on several occasions. It DOES take a bit of practice, but the line never seems to get tangled. I tried this with a few lead fishing weights on some thin nylon line and it was a disaster. The secret is to use a thick enough line so that it won't spin around itself and (mysteriously) tie itself in a knot way up in the tree. 73, Charlie k3ICH - Original Message - From: Fred Jensen k6...@foothill.net To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 8:05 PM Subject: Re: [Elecraft] RF in the Trees On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote: This may be off topic, but in light of it being Field Day Weekend in the US It's radio, Eric will probably see it as relevant, unless we overdo it, which we do at times. :-) The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. __ 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] RF in the Trees
Hmmm vertical dipole... vs... end fed half wave vertical dipole - not sure these are equivalent in performance. I know W8JI thinks the end fed half wave needs some sort of ground system-counterpoise to keep the feed line from becoming part of the antenna, so I am wondering - asking not telling - whether these two are really equivalent? (He said reaching for his ARRL Antenna Book...) I believe Jim K9YC modeled a true vertical dipole (including the n6BT end-loaded vertical dipole) - but I would expect it to work out differently from an end fed half wave vertical. The GAP antennas and Cuschraft R8 and R9 type are supposed to be loaded vertical dipoles, and are not, I don't think, end feds... but that is the question... are these really all equivalent? Certainly feeding at the bottom of an end fed would be easier from a construction and deployment point of view, so I can see the obvious appeal therefor, but then does it work as well as, say, the N6TB vertical dipole fed in the middle? Again, this is a question not a critique. K8JHR --- On 6/26/2014 10:59 AM, Doug Person via Elecraft wrote: The K9YC modelling with EZNEC http://k9yc.com/VertOrHorizontal-Slides.pdf is quite interesting. Certainly has me thinking about vertical dipoles. The half-wave end-fed looks like the perfect candidate for a simple vertical dipole. __ __ 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] RF in the Trees
Half-wave dipoles are equal no matter how they are fed. With an end-fed dipole, the short counterpoise advocated by W8JI is merely a method of accomplishing feed to that high impedance point. There is no difference in the radiation of any half wave dipole (except as influenced by ground, surrounding objects, etc.) - if you can couple RF into it, it will radiate. 73, Don W3FPR On 6/27/2014 8:51 AM, K8JHR wrote: Hmmm vertical dipole... vs... end fed half wave vertical dipole - not sure these are equivalent in performance. I know W8JI thinks the end fed half wave needs some sort of ground system-counterpoise to keep the feed line from becoming part of the antenna, so I am wondering - asking not telling - whether these two are really equivalent? (He said reaching for his ARRL Antenna Book...) __ 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] RF in the Trees
Why would it matter where it's fed? A half wave dipole has the same current distribution regardless of the feed point. Wes. N7WS On Jun 27, 2014, at 5:51 AM, K8JHR jricha...@k8jhr.com wrote: Hmmm vertical dipole... vs... end fed half wave vertical dipole - not sure these are equivalent in performance. I know W8JI thinks the end fed half wave needs some sort of ground system-counterpoise to keep the feed line from becoming part of the antenna, so I am wondering - asking not telling - whether these two are really equivalent? (He said reaching for his ARRL Antenna Book...) I believe Jim K9YC modeled a true vertical dipole (including the n6BT end-loaded vertical dipole) - but I would expect it to work out differently from an end fed half wave vertical. The GAP antennas and Cuschraft R8 and R9 type are supposed to be loaded vertical dipoles, and are not, I don't think, end feds... but that is the question... are these really all equivalent? Certainly feeding at the bottom of an end fed would be easier from a construction and deployment point of view, so I can see the obvious appeal therefor, but then does it work as well as, say, the N6TB vertical dipole fed in the middle? __ 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] RF in the Trees
There is special cord designed to not get stuck in trees. It is called arborist throw line. It really works, I use it for bear bagging on backpacking trips. You can get the line, a throw weight, and a storage bag as a throw kit. http://www.wesspur.com/throw-line/zing-it-throw-line.html wunder K6WRU On Jun 27, 2014, at 5:27 AM, Charlie T, K3ICH pin...@erols.com wrote: The professional Arborists use a cloth or leather bag filled with lead shot and something called tangle-free line or similar to throw up in a tree so that they can pull up a supporting rope for tree trimming etc. From what I've seen, the bag is about the size of a tear drop shaped golf ball. The idea of the shot instead of a solid weight is to make the bag less damaging if it hits your house (or window) on the way down. I have a neighbor who's son is an arborist, so I've watched him on several occasions. It DOES take a bit of practice, but the line never seems to get tangled. I tried this with a few lead fishing weights on some thin nylon line and it was a disaster. The secret is to use a thick enough line so that it won't spin around itself and (mysteriously) tie itself in a knot way up in the tree. 73, Charlie k3ICH - Original Message - From: Fred Jensen k6...@foothill.net To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 8:05 PM Subject: Re: [Elecraft] RF in the Trees On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote: This may be off topic, but in light of it being Field Day Weekend in the US It's radio, Eric will probably see it as relevant, unless we overdo it, which we do at times. :-) The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. __ 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 wun...@wunderwood.org -- Walter Underwood wun...@wunderwood.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] RF in the Trees
Good topic, but we're hotting the posting limit for a single topic. Let's wind this one down asap. Eric Your friendly jet lagged moderator (at the Freidrichshafen, Germany, Ham Radio show.) elecraft.com _..._ On Jun 27, 2014, at 5:23 PM, Walter Underwood wun...@wunderwood.org wrote: There is special cord designed to not get stuck in trees. It is called arborist throw line. It really works, I use it for bear bagging on backpacking trips. You can get the line, a throw weight, and a storage bag as a throw kit. http://www.wesspur.com/throw-line/zing-it-throw-line.html wunder K6WRU On Jun 27, 2014, at 5:27 AM, Charlie T, K3ICH pin...@erols.com wrote: The professional Arborists use a cloth or leather bag filled with lead shot and something called tangle-free line or similar to throw up in a tree so that they can pull up a supporting rope for tree trimming etc. From what I've seen, the bag is about the size of a tear drop shaped golf ball. The idea of the shot instead of a solid weight is to make the bag less damaging if it hits your house (or window) on the way down. I have a neighbor who's son is an arborist, so I've watched him on several occasions. It DOES take a bit of practice, but the line never seems to get tangled. I tried this with a few lead fishing weights on some thin nylon line and it was a disaster. The secret is to use a thick enough line so that it won't spin around itself and (mysteriously) tie itself in a knot way up in the tree. 73, Charlie k3ICH - Original Message - From: Fred Jensen k6...@foothill.net To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 8:05 PM Subject: Re: [Elecraft] RF in the Trees On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote: This may be off topic, but in light of it being Field Day Weekend in the US It's radio, Eric will probably see it as relevant, unless we overdo it, which we do at times. :-) The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. __ 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 wun...@wunderwood.org -- Walter Underwood wun...@wunderwood.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 elist_c...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] RF in the Trees
Sal, The main problem with kites is safety. One doesn't always know when the kite will change directions, dive or loop, with the potential of the kite wire crossing over a very deadly, high voltage utility line. Poof! You are vapor. 73, Terry, W0FM -Original Message- From: Slava Baytalskiy [mailto:sla...@nullserv.com] Sent: Thursday, June 26, 2014 6:25 PM To: Rick Bates, WA6NHC Cc: Elecraft Reflector Subject: Re: [Elecraft] RF in the Trees I wonder if anyone's ever used a kite in a field to keep a wire up. I see kites a lot in the summer, along belt parkway here in Brooklyn and they seem to stay in one place for long periods of time. I'm sure one can use 12 or 14 AWG wire and let a kite carry it pretty high. Of course you need wind for that but being near water (salt water, no less) there's usually wind present. Hmm. Another idea that may be used to place a wire with a lot of precision is one of those RC quadricopters that are becoming wildly popular. A little servo claw to release the wire or just to place it's apex where you want it... __ Slava (Sal) B, W2RMS w2...@arrl.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] RF in the Trees
typo - hitting the limit.. Eric elecraft.com _..._ On Jun 27, 2014, at 5:33 PM, Eric Swartz WA6HHQ - Elecraft e...@elecraft.com wrote: Good topic, but we're hotting the posting limit for a single topic. Let's wind this one down asap. Eric Your friendly jet lagged moderator (at the Freidrichshafen, Germany, Ham Radio show.) elecraft.com _..._ On Jun 27, 2014, at 5:23 PM, Walter Underwood wun...@wunderwood.org wrote: There is special cord designed to not get stuck in trees. It is called arborist throw line. It really works, I use it for bear bagging on backpacking trips. You can get the line, a throw weight, and a storage bag as a throw kit. http://www.wesspur.com/throw-line/zing-it-throw-line.html wunder K6WRU On Jun 27, 2014, at 5:27 AM, Charlie T, K3ICH pin...@erols.com wrote: The professional Arborists use a cloth or leather bag filled with lead shot and something called tangle-free line or similar to throw up in a tree so that they can pull up a supporting rope for tree trimming etc. From what I've seen, the bag is about the size of a tear drop shaped golf ball. The idea of the shot instead of a solid weight is to make the bag less damaging if it hits your house (or window) on the way down. I have a neighbor who's son is an arborist, so I've watched him on several occasions. It DOES take a bit of practice, but the line never seems to get tangled. I tried this with a few lead fishing weights on some thin nylon line and it was a disaster. The secret is to use a thick enough line so that it won't spin around itself and (mysteriously) tie itself in a knot way up in the tree. 73, Charlie k3ICH - Original Message - From: Fred Jensen k6...@foothill.net To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 8:05 PM Subject: Re: [Elecraft] RF in the Trees On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote: This may be off topic, but in light of it being Field Day Weekend in the US It's radio, Eric will probably see it as relevant, unless we overdo it, which we do at times. :-) The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. __ 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 wun...@wunderwood.org -- Walter Underwood wun...@wunderwood.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 elist_c...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to elist_c...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] RF in the Trees
On 6/27/2014 3:16 AM, Gerry leary wrote: Thanks very much for showing me HYpower Anntennas. They look very interesting, and I am going to call them with questions. When I was getting back on the air in 2003 in Chicago, I needed a shortened antenna for 80 and 40. I bought his shortened 80/40 dipole. It's a full size half wave on 40, with loading coils and more wire on each side for 80M. It worked fine. When I moved to CA, I bought only the loading coils for the comparable 160/80 version. I've since used those coils to build 160/80/40M antennas at two very different sites. I built the 160/80 per Barry's design, and added a fan element for 40M. 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] RF in the Trees
On 6/27/2014 6:30 AM, Don Wilhelm wrote: if you can couple RF into it, it will radiate. Yes. There are many ways to feed a vertical dipole. I developed a method that uses the outside of the coax as half of the dipole, and uses a ferrite choke to form the end insulator. The choke is positioned a quarter wave down the coax from the center insulator. I published this method about six years ago, after seeing a similar suggestion ftrom Rudy Severns, N6LF. Rudy used a coil of coax, forming only an inductor. My contribution was the ferrite choke, which makes the antenna insensitive to feedline length. The end of a dipole is a high voltage point, so there's considerable voltage across the choke if you're running much power. I tested this concept around 2008 on 40M with 1.5kW, and found that I needed two chokes in series, each of which was 5,000 ohms. A single choke would work quite well at 100W or less. Note that electrically, this dipole is center fed -- there's a quarter wave wire connected to the coax that goes to an end insulator that can be suspended in a tree, then the coax hangs down, and the choke is a quarter wave down from the wire. The impedance of a vertical dipole like this is about 70 ohms at resonance, which makes it a good match for 75 ohm coax. Remember that SWR in a system is determined by the match between the antenna and the line, so losses will be lower with 75 ohm coax. Also remember that the velocity factor of coax is for signals INSIDE the coax. For signals OUTSIDE the coax, the velocity factor is like any other insulated wire of comparable size, roughly 0.98. The choke should be wound using the guidelines in my Cookbook. 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] RF in the Trees
I don't really understand why traps have gotten such a bad rap. Consider that most all triband beams use traps as well as many verticals. I have been using Spi-Ro traps for 20 years and never had a problem and I certainly don't see any indication that I am suffering some kind of loss as a result. I have made many comparisons between the trapped dipoles and single band non-trapped dipoles and the only difference I see is a reduction in usable bandwidth. The Spi-Ro traps are rated for 600 watts making them perfect for the KPA500 powered station. Indeed - do not rule out traps. I also use a similar wire that to what Charlie mentions. Last order was for 600 feet. It's great stuff. Now I'm thinking of what would be the best all-band antenna for the K2 which is my secondary operating position in the living room where I can give demos to visitors. I'm thinking of giving the 88 foot doublet fed with 300 ohm twinlead a try. Doug -- K0DXV On 6/26/14, 6:30 AM, Charlie T, K3ICH wrote: Don't rule out traps. Also, the RF Connection and probably others, sell a nice stranded copperweld wire that has a black polyethylene insulation. If I remember correctly, it is 13 ga and is ideal for antennas. For all practical purposes, it doesn't stretch, is fairly slippery and only a little springier than hard drawn copper. I use those double ferrule aluminum crimp on's that are designed for flexible wire cable to hold everything together. I was concerned about them holding through the poly insulation, but the following antenna has been up for about ten years now. It consists of a double (fan) dipole with a pair of 80 meter traps in the top leg for 160 80 M coverage and a pair of 40 meter traps in the lower leg for 60 40 M coverage. It is fed thru a 1:1 balun with RG-213 and is tuned for resonance. Basically, I operate SSB 99% of the time, so the antenna is tuned for that end of the bands. An MN-2700 tuner in the shack takes care of small excursions from resonance. It's only up about 50 feet, so performance is what you'd expect. It's not straight either and is sort of a lazy Z, being strung between two 55' telephone poles that are 105 feet apart. The ends droop down at about 45 degrees to tie-off points in trees. A compromise? Yes, but it works. 73, Charlie k3ICH - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 1:55 AM Subject: Re: [Elecraft] RF in the Trees On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases
Re: [Elecraft] RF in the Trees
http://w5jgv.com/tree_antenna/index.htm Ralph is the ham I was referring to. Now you have as much as I am aware of. I forgot that Ralph wound a torus around the tree base. He used an old oak which brings song to mind tie a yellow ribbon around that ole oak tree The question about whether the tree feels the electrical field gets into the whole earth realm of whether flora feel as much a fauna? I would say, yes. The tree probably feels excited with an electrifying experience! :-D Long term effects on the health of a tree is probably unknown. Mankind generally does not have much empathy for the plant world. We grow it and we harvest it for food or shelter. 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@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] RF in the Trees
This is how we feel about the plant world: *John Barleycorn* There were three men came out of the West, Their fortunes for to try, And these three men made a solemn vow: John Barleycorn must die. They've ploughed, they've sown, they've harrowed him in, Threw clods upon his head, And these three men made a solemn vow: John Barleycorn was dead. They've let him lie for a very long time, Till the rains from heaven did fall, And little Sir John sprung up his head, And so amazed them all. They've let him stand till midsummer's day, Till he looked both pale and wan, And little Sir John's grown a long, long beard, And so become a man. They've hired men with the scythes so sharp, To cut him off at the knee, They've rolled him and tied him by the way, Serving him most barbarously. They've hired men with the sharp pitchforks, Who pricked him to the heart, And the loader he has served him worse than that, For he's bound him to the cart They've wheeled him around and around the field, Till they came unto a barn, And there they made a solemn oath, On poor John Barleycorn. They've hired men with the crab-tree sticks, To cut him skin from bone, And the miller he has served him worse than that, For he's ground him between two stones. And little Sir John and the nut-brown bowl, And he's brandy in the glass; And little Sir John and the nut-brown bowl, Proved the strongest man at last. The huntsman, he can't hunt the fox, Nor so loudly to blow his horn, And the tinker he can't mend kettle nor pot, Without a little Barleycorn With apologies to Traffic :) 73, Kevin. KD5ONS On 6/27/2014 11:18 AM, Edward R Cole wrote: http://w5jgv.com/tree_antenna/index.htm Ralph is the ham I was referring to. Now you have as much as I am aware of. I forgot that Ralph wound a torus around the tree base. He used an old oak which brings song to mind tie a yellow ribbon around that ole oak tree The question about whether the tree feels the electrical field gets into the whole earth realm of whether flora feel as much a fauna? I would say, yes. The tree probably feels excited with an electrifying experience! :-D Long term effects on the health of a tree is probably unknown. Mankind generally does not have much empathy for the plant world. We grow it and we harvest it for food or shelter. 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@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 kev...@coho.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] RF in the Trees
Doug - I've been using an 88 foot long doublet at 45 feet for about four years - works very, very well on 40-6 meters. It tunes on 80 but I have an inverted L I use there. Currently I feed it with about 110 feet of 450-ohm ladder line and a Current Designs 4:1 balun, and then about ten feet of RG-8X into the shack. My only complaint is that the SWR jumps all over the place when it's raining, which it normally does here in this part of the state in the winter. I may go back to 600-ohm open wire line later this summer. But other than that, the 88-foot doublet is a good performer. BTW - mine is made out of #26 silky coat wire from The Wireman in SC - I have to keep it stealthy, but have no problem running 500w to it from my Elecraft K3/KPA500. Jim / W6JHB Folsom, CA On Friday, Jun 27, 2014, at Friday, 10:40 AM, Doug Person via Elecraft wrote: Now I'm thinking of what would be the best all-band antenna for the K2 which is my secondary operating position in the living room where I can give demos to visitors. I'm thinking of giving the 88 foot doublet fed with 300 ohm twinlead a try. Doug -- K0DXV __ 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] RF in the Trees
This guy comae up with a variation on the OCF Dipole that matches well on many bands and has been field tested in contests by a station in Germany. Lightweight, low profile, durable, especially good for QRP or field day operations. Maybe it will give you an idea or two... I understand the developer spent countless hours modeling, testing, re-modeling, re-testing, etc., until he got the right feed point offset to maximize low SWR on multiple bands, as if looking for the holy grail of antennas. http://www.aerial-51.com/ I have no financial interest in any of it, but if the balun comes potted in epoxy, it was kinda my idea ... ;-) K8JHR -- On 6/27/2014 1:40 PM, Doug Person via Elecraft wrote: Now I'm thinking of what would be the best all-band antenna for the K2 which is my secondary operating position in the living room where I can give demos to visitors. I'm thinking of giving the 88 foot doublet fed with 300 ohm twinlead a try. _ __ 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] RF in the Trees
I also have one of their fan dipoles: full size 40, full size 20 with coils and more wire on the ends that gives me shortened 80. Excellent quality! Great price. Brian KB1VBF Sent from my iPad On Jun 27, 2014, at 6:16 AM, Gerry leary gerrylear...@icloud.com wrote: Thanks very much for showing me HYpower Anntennas. They look very interesting, and I am going to call them with questions. Gerry Sent from my iPhone this time On Jun 26, 2014, at 9:39 AM, Walter Underwood wun...@wunderwood.org wrote: For pre-built antennas, HyPower is a good choice. He has lots of options, fan dipoles, loaded dipoles, even combinations. I have a fan dipole made from a full-size 40m element and an element that is full-size for 80 and loaded for 80. He also sells the loading coils if you would rather DIY. http://www.hypowerantenna.com/ wunder K6WRU __ 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] RF in the Trees
End of thread. In the future, please self moderate and end threads as quickly as possible in the interest of better list SNR. 73, Eric Modulator elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] RF in the Trees
Hi Jim, This thread has been closed. Please take further discussion off list in the interest of reducing list overload for others. 73, Eric elecraft.com On 6/28/2014 9:32 AM, Jim Brown wrote: On 6/27/2014 6:30 AM, Don Wilhelm wrote: if you can couple RF into it, it will radiate. Yes. There are many ways to feed a vertical dipole. I developed a method that uses the outside of the coax as half of the dipole, and uses a ferrite choke to form the end insulator. The choke is positioned a quarter wave down the coax from the center insulator. __ 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] RF in the Trees
Don't rule out traps. Also, the RF Connection and probably others, sell a nice stranded copperweld wire that has a black polyethylene insulation. If I remember correctly, it is 13 ga and is ideal for antennas. For all practical purposes, it doesn't stretch, is fairly slippery and only a little springier than hard drawn copper. I use those double ferrule aluminum crimp on's that are designed for flexible wire cable to hold everything together. I was concerned about them holding through the poly insulation, but the following antenna has been up for about ten years now. It consists of a double (fan) dipole with a pair of 80 meter traps in the top leg for 160 80 M coverage and a pair of 40 meter traps in the lower leg for 60 40 M coverage. It is fed thru a 1:1 balun with RG-213 and is tuned for resonance. Basically, I operate SSB 99% of the time, so the antenna is tuned for that end of the bands. An MN-2700 tuner in the shack takes care of small excursions from resonance. It's only up about 50 feet, so performance is what you'd expect. It's not straight either and is sort of a lazy Z, being strung between two 55' telephone poles that are 105 feet apart. The ends droop down at about 45 degrees to tie-off points in trees. A compromise? Yes, but it works. 73, Charlie k3ICH - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 1:55 AM Subject: Re: [Elecraft] RF in the Trees On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander. http://k9yc.com/VertOrHorizontal-Slides.pdf When Fred observes that the ends of antennas are hotter, he means that this is voltage maxima and a current minima, so good insulation is needed to whatever the antenna is attached. I once melted heavy dacron rope that was tied directly to the end of said dipole (well, twice, actually). The extra ingredient was that it was wet. Duh. 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
Re: [Elecraft] RF in the Trees
This is an interesting discussion about antennas for forest regions where you have very tall trees.  I have a lot of trees, but getting an antenna to 45 or 50 feet would involve very small branches.  I have mostly Chinese Tallow Trees with some Ash and Beech, so stringing a wire from trees is marginal for me.  I do have a 65 foot tower and conductive soil, so the trombone elements from SteppIR work well for me.  You will be surprised how directive a rotatable dipole at 65 feet can be for 30 and 40 with 6 to 10 dB nulls at the ends and not much loss over a full dipole.  A 60 foot wire vertical from a ground stake to the top guy is a good 80 meter antenna and if you add an 80 meter trap and a drooping extension it pretty good for 160.  I have lived near a neighbor with 100 foot pine trees and I have seen them leaning nearly 45 degrees in 100 mile an hour winds during Hurricane Alicia.  I think a wire antenna would break.  Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ Trustee N5BPS, USS Cavalla, USS Stewart On Thursday, June 26, 2014 12:57 AM, Jim Brown j...@audiosystemsgroup.com wrote: On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander. http://k9yc.com/VertOrHorizontal-Slides.pdf When Fred observes that the ends of antennas are hotter, he means that this is voltage maxima and a current minima, so good insulation is needed to whatever the antenna is attached. I once melted heavy dacron rope that was tied directly to the end of said dipole (well, twice, actually). The extra ingredient was that it was wet. Duh. 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 wrco...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to
Re: [Elecraft] RF in the Trees [OT]
One of my Elmers showed me another way. Purposley choose the twig ends of the branch of a huge tree. Use this as your center of the dipole, or whatever. Blow a line all the way over the tree, and attach it to something other than the tree. Pull up the antenna, and leave rope line going down from the center point. Once you get the center where you want it, tie the dangling rope to something solid, like a Land Anchor. Pull the other side and tie it down to something solid as well, like another Land Anchor, or even the base of another tree. Now your center point is suspended towards the outside of a tree branch, and will not move up and down, as you have it anchored from above, and below even when the wind blows. Use the ends of the antenna to stop the antenna from moving side to side. The trick is not allowing the centerpoint to twist before you get the ends stretched out. Keith KB9WMJ - Original Message - From: Fred Townsend fptowns...@earthlink.net To: Doug Person k0...@aol.com; elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 12:19 AM Subject: Re: [Elecraft] RF in the Trees [OT] Hi Doug: I use a similar technique in suspending my antennas. I thought I would add some do's and don'ts. Like don't forget copper will stretch. I use 1 gallon paint buckets full of dirt for about 10# of weight on the pulleys. I suspend the rope in a tree yoke or a limb close to the trunk to minimize sway. Be sure there is pleanty of travel for wind storms. The ends of the antenna are 'hotter' than the feed point so I like to clear the end of the antenna and the tree with at least 8' of rope. If I have a middle support I use a yard arm of at least 4'. If you are using an antenna like a G5RV, Windom, or zepp that uses a portion of the feed line as a match, don't forget that portion will be radiating too so keep it vertical and away from the tree. I have found pine and eucalyptus trees to be the worst for parasitic absorption but I think that is largely a function of the volume of sap and water so the wetter the more loss and the further away you want to keep the antenna. 73, Fred, AE6QL __ 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] RF in the Trees
The K9YC modelling with EZNEC http://k9yc.com/VertOrHorizontal-Slides.pdf is quite interesting. Certainly has me thinking about vertical dipoles. The half-wave end-fed looks like the perfect candidate for a simple vertical dipole. Doug -- K0DXV On 6/25/14, 11:55 PM, Jim Brown wrote: On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander. http://k9yc.com/VertOrHorizontal-Slides.pdf When Fred observes that the ends of antennas are hotter, he means that this is voltage maxima and a current minima, so good insulation is needed to whatever the antenna is attached. I once melted heavy dacron rope that was tied directly to the end of said dipole (well, twice, actually). The extra ingredient was that it was wet. Duh. 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 k0...@aol.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] RF in the Trees
For pre-built antennas, HyPower is a good choice. He has lots of options, fan dipoles, loaded dipoles, even combinations. I have a fan dipole made from a full-size 40m element and an element that is full-size for 80 and loaded for 80. He also sells the loading coils if you would rather DIY. http://www.hypowerantenna.com/ wunder K6WRU On Jun 26, 2014, at 5:30 AM, Charlie T, K3ICH pin...@erols.com wrote: Don't rule out traps. Also, the RF Connection and probably others, sell a nice stranded copperweld wire that has a black polyethylene insulation. If I remember correctly, it is 13 ga and is ideal for antennas. For all practical purposes, it doesn't stretch, is fairly slippery and only a little springier than hard drawn copper. I use those double ferrule aluminum crimp on's that are designed for flexible wire cable to hold everything together. I was concerned about them holding through the poly insulation, but the following antenna has been up for about ten years now. It consists of a double (fan) dipole with a pair of 80 meter traps in the top leg for 160 80 M coverage and a pair of 40 meter traps in the lower leg for 60 40 M coverage. It is fed thru a 1:1 balun with RG-213 and is tuned for resonance. Basically, I operate SSB 99% of the time, so the antenna is tuned for that end of the bands. An MN-2700 tuner in the shack takes care of small excursions from resonance. It's only up about 50 feet, so performance is what you'd expect. It's not straight either and is sort of a lazy Z, being strung between two 55' telephone poles that are 105 feet apart. The ends droop down at about 45 degrees to tie-off points in trees. A compromise? Yes, but it works. 73, Charlie k3ICH - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: elecraft@mailman.qth.net Sent: Thursday, June 26, 2014 1:55 AM Subject: Re: [Elecraft] RF in the Trees On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander. http://k9yc.com/VertOrHorizontal-Slides.pdf When Fred observes that the ends of antennas are hotter, he means that this is voltage maxima and a current minima, so good insulation is needed to whatever the antenna is attached. I once melted heavy
Re: [Elecraft] RF in the Trees
That's a good and useful presentation. Although they don't affect Jim's vertical vs. horizontal conclusions, slides 22, 26, and 73 contain errors confusing quarter- and half wavelengths for 160/80/40 meters (i.e. 133 ft is a quarter wave on 160, not a half wave). John, KU4AF Pittsboro, NC Elecraft mailing list wrote The K9YC modelling with EZNEC lt;http://k9yc.com/VertOrHorizontal-Slides.pdfgt; is quite interesting. Certainly has me thinking about vertical dipoles. The half-wave end-fed looks like the perfect candidate for a simple vertical dipole. Doug -- K0DXV -- View this message in context: http://elecraft.365791.n2.nabble.com/RF-in-the-Trees-tp7590553p7590582.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] RF in the Trees
On 6/26/2014 9:17 AM, KU4AF wrote: Although they don't affect Jim's vertical vs. horizontal conclusions, slides 22, 26, and 73 contain errors confusing quarter- and half wavelengths for 160/80/40 meters (i.e. 133 ft is a quarter wave on 160, not a half wave). Thanks John. I had fixed that at least a month ago, but the corrected version didn't get to the website correctly. It's corrected now. 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] RF in the Trees
I have used trees to hang wire in the past. Now I use metal trees i.e. Rohn-25 and Rohn-45 metal trees. Much easier to climb and they do not sway near as much. Truthfully, the forest does not reach much higher than50-60 feet in my part of Alaska. We get 50-60 mph winds each year (mainly in Nov-Dec) which lays the native white spruce and birch trees over to about 30 to 45 degrees off plumb and no pulley system will handle that violence. I had my anemometer blown off one of the towers last winter. I guess it registered 65 when I came apart. Just got a phone call, yesterday, that it had been rebuilt and on its way back from the factory. Two falls ago we had some of the 60-foot spruce blown over that were pulled out by the roots! Had heavy rain for two months beforehand that softened the soil. I have two 50-foot ROHN-25 spaced 130 foot ad run an inverted-L between them and a 80/40m inverted-V hung from 40-feet on one at right angles to the inverted-L (which is tuned to 600m). We have one member of the ARRL Experimental Group on 600m that has actually loaded a pine tree to act as a vertical antenna, He wrapped a huge amount of wire around the base of the tree as a coupling coil. 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@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] RF in the Trees
My only method of raising wire into the air to act as dipoles (actually fan dipoles) are trees -- nice tall straight trees. In my case, Douglas Fir, Red Cedar, and Hemlock. Each tree is about 80 to 95 feet tall. I don't climb these trees though. All antennas launched via bow arrow with heavy fishing line that lifts up dacron line that lifts up insulated #12 house wire. One of my antennas is a 80/40 fan dipole with a home-made balun at the center (created with the help of Jim's, K9YC, RFI paper). The other is a 30-meter dipole. Wires up about 50 feet elevation. Never have had a problem and I have only had one break and I think that was caused by a squirrel looking for food inside of 3/8th Dacron line wrapped over the top of a tree branch. No problem, I'm getting pretty good with the bow arrow method of launching. 73, phil, K7PEH __ 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] RF in the Trees
Jim's presentation is excellent, covering lots of trade-offs that most of us face putting up antennas. There are a couple (at least) other aspects that should be considered. I've been using an end fed half wave vertical for several years with my K1 for portable ops. It's easy to put up on a 33 ft fiberglass pole and covers 40, 30, and 20 using loading coils on the lower bands. I couple it to the 50 ohm feed line using a link coupled tuned tank circuit to accommodate the very high feed point impedance. Since that impedance can be in the k-ohms, and the voltages involved increase as the square of the power, this setup is strictly a QRP deal. If I try to use more than about 20 w the toroid in the coupler begins to arc like a Tesla coil. The other thing I have encountered with verticals vs horizontal antennas in an urban environment is that verticals are inherently noisier. For weak signal situations (QRP Fox Hunts) I've compared the above vertical with my inverted V and found that the V wins out on receive SNR most of the time. I've noticed the same thing comparing vertical vs horizontal feed setups on a 20 m delta loop I had up for a while. 73, Brian, K0DTJ On 6/26/2014 7:59 AM, Doug Person via Elecraft wrote: Certainly has me thinking about vertical dipoles. The half-wave end-fed looks like the perfect candidate for a simple vertical dipole. __ 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] RF in the Trees
On 6/26/2014 1:38 PM, Brian Hunt wrote: I've been using an end fed half wave vertical for several years with my K1 for portable ops. EFHW's are very popular with the Summits On The Air crowd, and there are several varieties of transformers that will get the impedance down to what the ATU in a QRP rig can handle. Some have added links for band change, KT5X has a trapped EFHW. The other thing I have encountered with verticals vs horizontal antennas in an urban environment is that verticals are inherently noisier. True ... not always, but as a rule of thumb from many years ago, a vertical will likely be noisier. I have a GAP Titan up on the roof that I use for the top two WARC bands mostly. My other two wires will radiate but because the antennas are large compared to the wavelength, they tend to squirt my RF in all sorts of useless directions. There are times, however, that the vertical is as quiet as the tribander on 20m. I'm always amazed at how well my magnetic loop works when in the field. 73, Fred K6DGW - Northern California Contest Club - CU in the 2014 Cal QSO Party 4-5 Oct 2014 - 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] RF in the Trees
On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad phys...@mac.com wrote: I'm getting pretty good with the bow arrow method === For years I used a slingshot, firing a weight attached to a spinning reel. Worked pretty good. But last year I bought one of these gadgets: http://www.kr4loairboss.com/ It has a certain gee-whiz factor that makes you feel like a naughty kid. 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] RF in the Trees
I have a theory about this. Compare a vertical to a dipole. One reason for additional noise is that a vertical is omnidirectional, and noise comes from all directions. The signal is coming from one direction, and if it is the right direction, then the 2.2 dB gain from directivity of a dipole improves the s/n ratio by that much. But subjectively the difference seems greater than this. It's also true that the vertical is better for signals off the side of the dipole. As Brian said, most verticals appear to be far noisier in urban environments where there is a lot of manmade noise. I believe that this is /not/ because manmade noise tends to be vertically polarized, as is often said. I believe that it is because most verticals are not adequately decoupled from the feedline. Therefore, manmade noise is picked up on the outside of the feedline and flows directly into the antenna. This is exactly the same problem that happens with a dipole without a balun. Therefore the solution to the problem may be a good choke 'balun' at the vertical's feedpoint. On 6/26/14 1:38 PM, Brian Hunt wrote: The other thing I have encountered with verticals vs horizontal antennas in an urban environment is that verticals are inherently noisier. -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ __ 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] RF in the Trees
This may be off topic, but in light of it being Field Day Weekend in the US The problem with the bow or slingshot is when (if) the projectile comes down. The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. The slingshot can improve over the arrow by increasing mass but can be equally dangerous. Accurate shots are challenging. Here is what I use (no pecuniary interest) and it solves those issues. http://www.antennalaunchers.com/antlaunching.html It is simple to use, moderately safe (standard weapon rules about pointing etc) and accurate shots are simple. I've used it to clear (and then some) 200' trees. A weighted tennis ball (of a BRIGHT color so it can be seen) is simple to make an accurate shot; can pass through, then be pulled to earth by the increased mass. If you clear the tree and want to shorten the flight path, simply touching the fishing line stops momentum immediately, the ball falls. So there are several options, some safer than others, some more expensive and they all work. What works best for you is the choice but please be safe and wear a hardhat. I've also seen someone using the antenna launcher to shoot tennis balls for their dog to chase. A 100 yard shot is pretty easily done. By the time the (tiring) dog came back with the ball, the launcher was ready to shoot again. 73, Rick, WA6NHC iPad = small keypad = typos = sorry ;-) On Jun 26, 2014, at 3:02 PM, Tony Estep estept...@gmail.com wrote: On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad phys...@mac.com wrote: I'm getting pretty good with the bow arrow method === For years I used a slingshot, firing a weight attached to a spinning reel. Worked pretty good. But last year I bought one of these gadgets: http://www.kr4loairboss.com/ It has a certain gee-whiz factor that makes you feel like a naughty kid. 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 happymooseph...@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] RF in the Trees
I wonder if anyone's ever used a kite in a field to keep a wire up. I see kites a lot in the summer, along belt parkway here in Brooklyn and they seem to stay in one place for long periods of time. I'm sure one can use 12 or 14 AWG wire and let a kite carry it pretty high. Of course you need wind for that but being near water (salt water, no less) there's usually wind present. Hmm. Another idea that may be used to place a wire with a lot of precision is one of those RC quadricopters that are becoming wildly popular. A little servo claw to release the wire or just to place it's apex where you want it... __ Slava (Sal) B, W2RMS w2...@arrl.net On Jun 26, 2014, at 7:12 PM, Rick Bates, WA6NHC happymooseph...@gmail.com wrote: This may be off topic, but in light of it being Field Day Weekend in the US The problem with the bow or slingshot is when (if) the projectile comes down. The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. The slingshot can improve over the arrow by increasing mass but can be equally dangerous. Accurate shots are challenging. Here is what I use (no pecuniary interest) and it solves those issues. http://www.antennalaunchers.com/antlaunching.html It is simple to use, moderately safe (standard weapon rules about pointing etc) and accurate shots are simple. I've used it to clear (and then some) 200' trees. A weighted tennis ball (of a BRIGHT color so it can be seen) is simple to make an accurate shot; can pass through, then be pulled to earth by the increased mass. If you clear the tree and want to shorten the flight path, simply touching the fishing line stops momentum immediately, the ball falls. So there are several options, some safer than others, some more expensive and they all work. What works best for you is the choice but please be safe and wear a hardhat. I've also seen someone using the antenna launcher to shoot tennis balls for their dog to chase. A 100 yard shot is pretty easily done. By the time the (tiring) dog came back with the ball, the launcher was ready to shoot again. 73, Rick, WA6NHC iPad = small keypad = typos = sorry ;-) On Jun 26, 2014, at 3:02 PM, Tony Estep estept...@gmail.com wrote: On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad phys...@mac.com wrote: I'm getting pretty good with the bow arrow method === For years I used a slingshot, firing a weight attached to a spinning reel. Worked pretty good. But last year I bought one of these gadgets: http://www.kr4loairboss.com/ It has a certain gee-whiz factor that makes you feel like a naughty kid. 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 happymooseph...@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 sla...@nullserv.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] RF in the Trees
This may be off topic, but in light of it being Field Day Weekend in the US The problem with the bow or slingshot is when (if) the projectile comes down. The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. The slingshot can improve over the arrow by increasing mass but can be equally dangerous. Accurate shots are challenging. In my case, the arrows I shoot up into and over trees always land on my property and I am the only one on my property at the time. So, not much chance of hurting anyone. I don't think my bow has enough power to launch an arrow off of my property. Not that my property is that great, more that my bow is not that powerful (30 lb maximum pull). It is just good enough to launch up into and over my trees. I have never had an arrow get hung up in branches in all of my experience with the bow. I think maybe I am just lucky though. 73, phil, K7PEH __ 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] RF in the Trees
On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote: This may be off topic, but in light of it being Field Day Weekend in the US It's radio, Eric will probably see it as relevant, unless we overdo it, which we do at times. :-) The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down. Should it comes later, the risks of impalement can ruin the day. I wrapped some heavy, old solder I had around the arrow tip in two layers, and then wrapped that with electrical tape. So far, it's always come down ... sometimes takes a little while with wind moving the branches. The two layers of solder make the tip very blunt, impalement is unlikely, bruise maybe if you don't have a hat on. Regardless of how you do it, my experience is that an Inv-V with the apex pulled up close to a limb but with the legs pulled out from the tree works just fine. It's hard to beat a horizontal 80m dipole with the center between two 90 ft pine or fir trees more than a wavelength apart, but sometimes we obsess about antennae minutiae. The slingshot can improve over the arrow by increasing mass but can be equally dangerous. Accurate shots are challenging. Arrow works better for me in the field, but the slingshot is a lot smaller and lighter. There's a reason arrows are long although the sling worked for David, I guess. 73, Fred K6DGW - Northern California Contest Club - CU in the 2014 Cal QSO Party 4-5 Oct 2014 - 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] RF in the Trees
On 6/26/2014 4:24 PM, Slava Baytalskiy wrote: I wonder if anyone's ever used a kite in a field to keep a wire up. I see kites a lot in the summer, along belt parkway here in Brooklyn and they seem to stay in one place for long periods of time. I'm sure one can use 12 or 14 AWG wire and let a kite carry it pretty high. Of course you need wind for that but being near water (salt water, no less) there's usually wind present. Hmm. The original German Notsender, forerunner of the WW2 Gibson Girl emergency beacon [AN/CRT-5] used a folded box kite, launched by a rocket from an inflatable raft ... let's see -- rocket in an inflatable raft, this conjures up many scenarios, most of them bad. The CRT-5 operated on the Holy Frequency [600 meters] and had a weighted copper braid to drop overboard into the salt water, and the ones we had used balloons inflated with hydrogen to lift the antenna. That was problematical in anything but a dead calm. I doubt most kites in most situations would handle #12 or even #14 wire, the high part of the wire ends up being a long way up toward the kite. Another idea that may be used to place a wire with a lot of precision is one of those RC quadricopters that are becoming wildly popular. A little servo claw to release the wire or just to place it's apex where you want it Monofilament line, sounds like a great idea! Pull a Dacron line up and then the wire. 73, Fred K6DGW - Northern California Contest Club - CU in the 2014 Cal QSO Party 4-5 Oct 2014 - 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] RF in the Trees
Hmmm. Interesting theory Vic. I agree that ambient noise probably doesn't have any particular polarization. My dipoles clearly have less noise pickup than my verticals. I do have a Cushcraft MV-6 compact vertical on top of the garage which has a balun as part of its design and it's noise level seems lower than the ground mounted verticals. But, it also has negative gain compared to a dipole or a full-size vertical. I was planning an experiment consisting of a full size vertical radiator made of aluminum tubing and two horizontal ground planes made of carefully tuned ham sticks. Now, I'll be sure to feed it through a good current balun to insure the feedline is fully decoupled. Another experiment on the summer agenda is a full-wave loop configured as a vertical rectangle to produce a 50 ohm feed point. I've read that a full wave loop is much better at rejecting noise and produces a lower angle of radiation for a given height than a dipole. I'd love to put up a quad, but $600 is a bit much right now. A full wave loop costs almost nothing by comparison. I'm wondering if perhaps a delta loop could be effective as a portable radiator for the KX3. An inverted triangle fed from the bottom apex seems simple enough. With summer finally here it is time to pull out the boxes of wire, coax and insulators and see what sort of interesting things to build. Doug -- K0DXV On 6/26/14, 4:07 PM, Vic, K2VCO wrote: I have a theory about this. Compare a vertical to a dipole. One reason for additional noise is that a vertical is omnidirectional, and noise comes from all directions. The signal is coming from one direction, and if it is the right direction, then the 2.2 dB gain from directivity of a dipole improves the s/n ratio by that much. But subjectively the difference seems greater than this. It's also true that the vertical is better for signals off the side of the dipole. As Brian said, most verticals appear to be far noisier in urban environments where there is a lot of manmade noise. I believe that this is /not/ because manmade noise tends to be vertically polarized, as is often said. I believe that it is because most verticals are not adequately decoupled from the feedline. Therefore, manmade noise is picked up on the outside of the feedline and flows directly into the antenna. This is exactly the same problem that happens with a dipole without a balun. Therefore the solution to the problem may be a good choke 'balun' at the vertical's feedpoint. On 6/26/14 1:38 PM, Brian Hunt wrote: The other thing I have encountered with verticals vs horizontal antennas in an urban environment is that verticals are inherently noisier. __ 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] RF in the Trees
Short wave listeners use kites and baloons to hold up long wire antennas all the time. I did this long before becoming a ham. -- K8JHR -- On 6/26/2014 7:24 PM, Slava Baytalskiy wrote: I wonder if anyone's ever used a kite in a field to keep a wire up. __ 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] RF in the Trees
I remember that Benjamin Franklin was a short wave listener -- his radio used a rusty key as the detector. His resonant circuit included a Leyden Jar capacitor. He quit this hobby though when, during an electrical storm, his lightning protection failed and destroyed his rig. Embarrassed about making such foolish mistakes, he invented an entirely different story to account for his being out in the storm flying a kite. 73, phil, K7PEH On Jun 26, 2014, at 9:31 PM, K8JHR jricha...@k8jhr.com wrote: Short wave listeners use kites and baloons to hold up long wire antennas all the time. I did this long before becoming a ham. -- K8JHR -- On 6/26/2014 7:24 PM, Slava Baytalskiy wrote: I wonder if anyone's ever used a kite in a field to keep a wire up. __ 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 phys...@mac.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] RF in the Trees [OT]
I run the following antennas in some pretty serious forest, and I get great results with them all: - 160M Inverted L with elevated radials over Pine trees. The tree is about 90ft tall and then the insulated wire loops over a branch - 80M Vertical also will elevated radials (the rope goes over a branch at 90ft) - 80M V with the apex at 70ft over a single Pine tree - 132ft Windom supported at both ends with a center support over hardwood trees at 60ft. In all cases, you have to be created to allow for flex as the wind blows. It has taken some trial and effort, but you'll figure it out by watching things move. Yes, you'll break it a few times, but eventually you'll come up with a solution. The worst case for moving resonance is the Windom, but that is easy to deal with. The 160M vertical varies is resonance point, but that is due to the ground conductivity changing from winter to summer. As I mentioned earlier, just do it. It will work. I have used both air cannons and my quad copters to drop my lines in place. Mike va3mw __ 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] RF in the Trees
I use a similar approach. I have a very strong Kevlar line strung between two tall trees and the dipoles are at least 40 feet from either tree. My dipoles at 60 feet out perform my beam at 30 feet by a substantial margin. Doug, K0DXV On 6/25/14, 6:43 PM, Dauer, Edward wrote: I have been playing with the two-tree solution to the one tree problem, with a family of inverted Vees (and a K3 and KX3, for keeping this on topic). The one tree problem is that a Vee hoisted onto a top limb of a coniferous tree is inevitably too close to if not tangled into the branches below the apex. So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. The surrounding forest is very likely still a problem, but that's life in the woods. Ted, KN1CBR Message: 8 Date: Wed, 25 Jun 2014 12:14:27 -0700 (GMT-07:00) From: Fred Townsend fptowns...@earthlink.net To: Rstafford12 rstaffor...@gmail.com, elecraft@mailman.qth.net Subject: Re: [Elecraft] extended double Zepp Message-ID: 18197016.1403723667813.javamail.r...@elwamui-huard.atl.sa.earthlink.net Content-Type: text/plain; charset=UTF-8 Richard: I have run a double Zepp hung from the trees as you suggest. If you can do it I would get the antenna across the tops of the trees. 45' is too low for 80M unless you are running NVIS in which case you are too high at 45'. Keep in mind that pine trees are parasitic so keep the wire, even if insulated, away from the trees. Inverted V works if you can't maintain 60'. 73, Fred, AE6QL -Original Message- From: Rstafford12 rstaffor...@gmail.com Sent: Jun 25, 2014 11:12 AM To: elecraft@mailman.qth.net Subject: [Elecraft] extended double Zepp I realize this is another somewhat not on topic post, but it is in regards to my KX1 and KX3. I have a mature pine forest; 60 -70 foot trees. How compromised would an EDZ be hung 45 feet up about four rows of trees in from the perimeter? No branches or needles inside the forest until 50 feet up. Richard KD0NPM __ 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 k0...@aol.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] RF in the Trees [OT]
The best trick I've found in dealing with moving trees is running the line through a pulley down to a weight that is heavy enough to keep the things reasonably taught. The trees can move all the want and the line just rides on the pulleys. Doug -- K0DXV On 6/25/14, 6:51 PM, Michael Walker wrote: I run the following antennas in some pretty serious forest, and I get great results with them all: - 160M Inverted L with elevated radials over Pine trees. The tree is about 90ft tall and then the insulated wire loops over a branch - 80M Vertical also will elevated radials (the rope goes over a branch at 90ft) - 80M V with the apex at 70ft over a single Pine tree - 132ft Windom supported at both ends with a center support over hardwood trees at 60ft. In all cases, you have to be created to allow for flex as the wind blows. It has taken some trial and effort, but you'll figure it out by watching things move. Yes, you'll break it a few times, but eventually you'll come up with a solution. The worst case for moving resonance is the Windom, but that is easy to deal with. The 160M vertical varies is resonance point, but that is due to the ground conductivity changing from winter to summer. As I mentioned earlier, just do it. It will work. I have used both air cannons and my quad copters to drop my lines in place. Mike va3mw __ 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 k0...@aol.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] RF in the Trees [OT]
Hi Doug: I use a similar technique in suspending my antennas. I thought I would add some do's and don'ts. Like don't forget copper will stretch. I use 1 gallon paint buckets full of dirt for about 10# of weight on the pulleys. I suspend the rope in a tree yoke or a limb close to the trunk to minimize sway. Be sure there is pleanty of travel for wind storms. The ends of the antenna are 'hotter' than the feed point so I like to clear the end of the antenna and the tree with at least 8' of rope. If I have a middle support I use a yard arm of at least 4'. If you are using an antenna like a G5RV, Windom, or zepp that uses a portion of the feed line as a match, don't forget that portion will be radiating too so keep it vertical and away from the tree. I have found pine and eucalyptus trees to be the worst for parasitic absorption but I think that is largely a function of the volume of sap and water so the wetter the more loss and the further away you want to keep the antenna. 73, Fred, AE6QL , -Original Message- From: Doug Person via Elecraft elecraft@mailman.qth.net Sent: Jun 25, 2014 8:03 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] RF in the Trees [OT] The best trick I've found in dealing with moving trees is running the line through a pulley down to a weight that is heavy enough to keep the things reasonably taught. The trees can move all the want and the line just rides on the pulleys. Doug -- K0DXV __ 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] RF in the Trees
On 6/25/2014 5:43 PM, Dauer, Edward wrote: So, I've been selecting two of the tallest candidates a couple of hundred feet apart and stringing a stout nylon rope between them. In the middle of the cord I attach the balun for the Vees, thereby allowing the legs to be in the clear, moveable from side to side, and tied to smaller (8') trees at their distal ends. In one variation on the theme I had a 40 meter dipole as the center section of the supporting rope, tied to the same balun as an 80 meter vee. In another I tried a linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't perform as well as the full length version. If you can suspend a flat antenna between two tall trees, why would you want an inverted vee, which is a less effective radiator? Your two trees 200 ft apart could support a full size 80/40 fan and a 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good antenna, and is easy to build. My technique has evolved to starting with #8 bare copper from the big box store, stretch it VERY slowly between a tree and a trailer hitch until it breaks. Do this carefully where there's no one around to get hurt. Now you have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) for the other elements. I make spacers by cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in place by soldering short lengths of copper around the spacer to the bare copper of the long element. The higher your antenna is, the more robust your center insulator should be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft 80/40 fans are fed with Belden 8213. For weights, I fill 6 gallon water jugs with dry sand, and tie one to one end of each span. The other end can be fixed. I have pulleys high my trees. If you don't have a pulley and weight, your antenna WILL end up on the ground, and it won't take a big storm for that to happen. My HF antennas are all at the 110-120 ft level in a dense redwood forest that towers 50-75 ft above them. They work. My seat of the pants observation is that attenuation increases with frequency, and is greatest with vertical polarization. 432 MHz is a waste of time, 2M sort of works, and 6M works pretty well. For an analysis of the value of height, study this. It supports the statement earlier in this thread that a high dipole beats a low tri-bander. http://k9yc.com/VertOrHorizontal-Slides.pdf When Fred observes that the ends of antennas are hotter, he means that this is voltage maxima and a current minima, so good insulation is needed to whatever the antenna is attached. I once melted heavy dacron rope that was tied directly to the end of said dipole (well, twice, actually). The extra ingredient was that it was wet. Duh. 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
