longish wave antenna wire? (self supporting wire?) - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 01:39:04 am
content: For setting up longwave antennas for experiments, what are some good wires to use? I.e. to string up a antenna between trees or such.Like if I was going to get a spool of wire, what should I get?I was thinking a teflon insulated solid core silver plated wire.But I was wondering if there are better options, not sure if they would work, i.e. a wire with a steel reinforcement, either as a inner core or like something the phone company uses (so its like speaker wire, with 1 steel wire an 1 copper wire, with the steel wire being the thing you bind for structural reasons and the copper the part that carries the signal).Recommendations on gauge, insulation type, other factors too are wanted too.And not sure how steel would effect it.Not sure what the 'mechanical' twin lead is called, I know you can get self supporting cable, with the steel strand, but I never saw self supporting copper wire.I can also imagine you can make it by zip-tying or heat shrinking copper wire to steel or stainless steel cable at regular intervals to make a DIY version thats not as nice as a extruded one. I guess you would still need insulated supports for the steel part. I was thinking to put insulated marine grade stainless steel cable (high flex type) zip tied to copper wire for instance.And in general, what effect would self supporting wire have on an antenna?Is there a big difference if the support wire:1) is isolated from the antenna wire, and tied to a ground conductor (parallel capacitor) , i.e. you bolt the wire to a grounded conductor, I imagine this is bad2) if the support wire is insulated from ground conductors but also isolated from the antenna wire (so there is a capactively connected floating stainless or iron strand against the antenna wire that is not connected to ground), so if you put a ceramic or plastic insulator for the support wire thats floating3) if its isolated from the ground but shorted to the antenna wire (this would just make the antenna slightly more conductive but its not appealing for mechanical reasons), I think its the best choice but how much difference is it from 2?

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 06:39:38 pm
content: also for connecting to a stainless steel cable (like garage cable), what would be the best way to do that?The best I can think of is to remake the aluminum crimp they sell out of copper, possibly silver plate it, then crimp to both the cable and the copper wire.there are also these, but IDK if its suitable for a steel woven rope, it seems to be meant for a solid steel conductor. I think the crimp would be better?https://www.zoro.com/burndy-copper-cable-to-steelfence-postflat-kc23b1/i/G4701225/

author: fourfathom
author_rank: Super Contributor
timestamp: March 03, 2023, 07:20:30 pm
content: Look at "Copperweld" (tm) wire, which is copper-plated steel. This is pretty traditional for long antenna wires. Here's a link to one vendor, but there are many sources:https://www.dxengineering.com/parts/dxe-antcw18-500#overviewI've used it myself, but more recently I've been using #12 stranded copper wire (I have hundreds of feet of the stuff from when a water-well was recommissioned), and I've also strung plenty of long dipoles (70 ft or so) using plain #14 copper house wire. People worry about stretch and strength of plain copper, but this hasn't been a problem for me. I suppose it depends on the length and conditions.Plain stainless cable isn't too bad either. The resistance is worse than copper (or silver plating!) but given the impedance of a dipole or long wire antenna it's not a huge deal. And if you're using a long wire then the frequency is probably HF or lower, so the atmospheric noise will likely dominate any loss of sensitivity caused by wire resistance.

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 08:03:26 pm
content: Well maybe its just me, but the self supporting wire seems fun to make. I have the proper wire cutters for the steel cable, and it seems like it would be really good compared to just hanging copper, and of course I don't like plated wire. I think copper + steel weave is going to be more flexible too, for rolling up in a spool. Stranded copper wire would also work much better at long distances with the support wire installed. t3slacoil wrote some interesting things about stranded wire having litz characteristics of some kind too, compared to single strand wire (weak). Kinda wonder about LITZ antennas too, since with a support wire they would be strong enough!I guess this is not a common idea.. I bought the knipex steel cable cutters to fix a garage door and I have been itching to find a use for some steel cable lol

author: fourfathom
author_rank: Super Contributor
timestamp: March 03, 2023, 08:38:28 pm
content: Interesting about the Litz effect in non-insulated stranded wire. But I doubt that it matters much (as in measurable) in a resonant HF or lower dipole, or non-resonant long-wire. My intuition is that because of the huge difference between free-space characteristic Z (377 Ohms), or the feedpoint Z of a halfwave dipole (72 Ohms), and the winding resistance/loss characteristics in a switching-regulator transformer. But sure, if you get a 0.01dB improvement for free, why not take it.So again, how long is the antenna going to be? What frequency range? I assume you are looking for a practical solution...My sailboat backstay antenna is close to 1cm dia stainless stranded cable, about 40 ft long between the insulators. It works well enough that I don't worry about any loss -- there's plenty of loss elsewhere, probably mostly in the tuner and seawater ground system.

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 08:39:56 pm
content: I don't know, I thought i would just make a spool of the stuff for when I find a suitable place to put one

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 08:41:18 pm
content: for a sail boat it seems interesting to be able to drop some weighted bouys with posts and string a extra long antenna out in the middle of no where when you are anchored some where

author: fourfathom
author_rank: Super Contributor
timestamp: March 03, 2023, 08:56:25 pm
content: Quote from: coppercone2 on March 03, 2023, 08:41:18 pmWhen I'm using the sailboat radio, the nearest land is usually about 2.5 miles -- straight down! So I can't anchor very easily.A long antenna close to the ground is called a "Beverage" antenna, after the guy that developed it (interesting history there). I believe it relies on having a lossy ground (dirt), so I don't know how it would do over seawater. But a seawater groundplane works extremely well for vertical antennas, giving an excellent low-angle pattern. Of course my backstay has a slope to it, so the pattern is no doubt distorted.

author: coppercone2
author_rank: Super Contributor
timestamp: March 03, 2023, 09:55:37 pm
content: that brings another project to mind, a bouy with a gyroscope mechanism in it to keep it up right like a segway or whatever. But I don't know about stringing up wire antennas at all, even less on water. Not sure exactly how that would work, a counter weight or water jets like control thrusters. That would be interesting to be able to drop a payload off the back of a boat and have it transform into a wire antenna array, with control water jet thrusters buoys can position themselves and then string up an antenna via catspan. I think it needs active thrust systems to stay in the same place without an anchor regardless how you balance it.With thin wire and telescoping fiberglass tubes I can imagine it could be made pretty tall in calm water/wind conditions with a mechanism. I wonder how useful and expensive that would be. Like the deployable water craft from red alert 3. Maybe someone in the pacific islands can build it lol, its alot more approachable then trying to deploy a satellite.Ever find one of those palm trees growing on 2 square meters of land in the ocean like cartoons?https://www.quora.com/Are-there-actually-any-tiny-islands-less-than-5-meters-diameter-with-1-3-palm-trees-like-the-ones-you-see-in-cartoons-that-appear-naturallyPark a boat next to it and string antenna between island and boat. Or two boats.https://antiqueradios.com/forums/viewtopic.php?t=80253hehe or if you are already powering it, I wonder how far off we are from a rather tall tower being supported upright by actual thrusters. Like fuel burning thrusters of some kind. Unlike a structure on land, if you fail in the water, all that happens is that a tall stick collapses in the water.Or since you are on water.......... what if it just had a pump on the bottom and water jets to stabilize it on top? I guess you would need a pretty powerful power source, but for a temporary beacon.. I wonder. Just pump the water up and use solenoids to keep it upright. Like those jet ski jetpack, but instead for stabilizing a tall antenna tower. Wonder what kind of material you would need to make it actually portable and stuff. maybe something like a garden spinning sprinkler could keep it up right with wobble/ungulation. Unstable but upright.Like... this is getting pretty mechanical, but I wonder if you can make something like that out of a jet ski. Turn a jetski into a actively stabilized tower buoy.. Those water jet packs can keep a man in the air via a trailing jetski, I wonder how big a tower could be stabilized that way.but instead of lifting it in the air, just preventing it from tipping over. So basically attach a hollow sealed telescoping rod to a jetski with something on top to direct the stream in such a way to keep it upright I also think it gains strenght from being pressurized with the water, but its heavy, IDK how that would work out. Or just put a extra high tower on a boat with a pump that is attached by some kind of ball joint or something so it makes the boat capable of supporting a much taller structure then usual, but that seems dangerous, I think you would want it away from the boat before it starts

author: Nassau Cable
author_rank: Newbie
timestamp: March 07, 2023, 04:34:52 pm
content: Hello. When selecting a wire for a longwave antenna, there are several key factors to consider. The most important ones are the wire's ability to conduct electricity, flexibility, and durability.Copper wire is frequently used for antennas due to its high conductivity. However, it may not be the most robust or flexible option. The solid-core wire is stiffer, making it easier to maintain a specific shape, while the stranded wire is more adaptable and may be easier to work with in certain scenarios.Teflon insulation is an excellent option because it has a high melting point and is resistant to moisture, which is essential for outdoor antennas. Go tohttps://nassaunationalcable.com/search?q=teflon&type=productand a see a couple of teflon wire references.Steel wire is not recommended for antennas because it is not highly conductive, and it can also interfere with the signal. This is also true for any other metal reinforcement. Thicker wire is generally preferable for longwave antennas since it has less resistance, resulting in less signal loss. A wire gauge of 14-16 is often recommended.When it comes to self-supporting wire, the usual recommendation is to keep the support wire isolated from the antenna wire and ground conductors to avoid interference.In summary, a solid-core or stranded copper wire with Teflon insulation and a thickness of 14-16 gauge is a good choice for a longwave antenna. If you need a quote, you cancontact NNC aand they will send it to you.

author: coppercone2
author_rank: Super Contributor
timestamp: March 07, 2023, 09:39:37 pm
content: https://www.wimo.com/en/hfw-2-mk2Look at that one, the only problem is that its PVC coated, but it has a shorted internal steel cable. I guess you can put a braid over a steel cable too.I do like teflon though, I do not have high hopes for PVC being outside, especially flexible PVCI wonder what wire length you would need to justify the steel support, I figure for anything but the longest installations the copper is strong enough.

author: fourfathom
author_rank: Super Contributor
timestamp: March 07, 2023, 11:02:41 pm
content: coppercone, how long do you anticipate this antenna wire is going to be? "Long" means different things to different people, and the mechanical (and electrical) requirements will vary a lot. As an example of "not overthinking it", I've had antennas made from 65 feet of PVC-insulated #14 solid house wire, and they stayed up for decades without trouble. I've also used #14 solid wire where I stripped off the insulation and again, no problems for years at a time.As for stabilizing an antenna buoy at sea, the practical approach is to use a float with heavy ballast down deep, and the antenna stuff as lightweight as practical. And rather than a spherical buoy, you want something with more of a pancake shape for added "form stability". I can't imagine an actual antenna application where your active stabilization methods would be practical. Ocean-going HF antennae are typically vertical for mechanical simplicity, and to take advantage of the good seawater groundplane. With a vertical, most of the RF energy is directed towards the horizon where you want it. Of course this all depends on frequency and application.There is a Ham thing called "IOTA", which stands for "Islands On The Air", where you take your rig ashore to some island and make contacts. Where I live there are plenty of islands, I should try it. I think the rules require that you operate on land, not from an anchored boat.

author: coppercone2
author_rank: Super Contributor
timestamp: March 07, 2023, 11:15:23 pm
content: I don't know when are where the opportunity will arise, I am just trying to learn about the construction methodsi made this more general threadhttps://www.eevblog.com/forum/mechanical-engineering/wire-antenna-gauge-strenght-distance-requirement/