Generic diagram. Elements not to scale.
Hoist full-wave loop antennas by kite.
A single kite of adequate size can hoist aloft a full-wave loop. I’ve coded a calculator in LabVIEW for solving the pertinent dimensions together with other relevant factors: wire mass, required tension at assumed flight angle, etc.
Generic diagram. Elements not to scale.
SOTAbeams in the UK sells a complete kit: a kite and all the related gear. Their SOTAkite is a hybrid type called a power sled. Which is to say, a mixed breed affair. Sled kites date from the 1950s, foil kites (modeled after a parafoil) from the 1970s. A power sled combines the virtues of both. See diagram below.
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There being no fun in simply repeating somebody else’s tried-and-true method, I set my sights somewhat higher. Or better to say, heavier. This while preserving air-travel portability. Below I compare the SOTAkite against four sizes sold by Premier Kites.
| Kite Model | Dimensions | Area | String* | Winds* | Link |
|---|---|---|---|---|---|
| SOTAkite | 168cm x 100cm | 1.68m2 | 55kg (121lbs) | 8-29kph (5-18mph) | SOTAbeams |
| PowerSled 14 | 160cm x 109cm | 1.74m2 | 41kg (90lbs) | 8-32kph (5-20mph) | Premier Kites |
| PowerSled 24 | 242cm x 113cm | 2.73m2 | 145kg (320lbs) | ||
| Jumbo PowerSled 36 | 323cm x 150cm | 4.85m2 | 227kg (500lbs) | ||
| Mega PowerSled 81 | 452cm x 210cm | 9.53m2 | 454kg (1000lbs) |
The on-line store for Premier Kites is frequently out-of-stock. Find them on EBay, when so. I bought one each of sizes 14, 24, and 36. The size 81 is tempting, but outside my price range. Also, just a bit scary.
To date I have flown PowerSled sizes 14 and 24, but not yet the 36. Both of those times under variable winds gusting to a little above recommended top range. Both flew high and held stable at line angles of about 60 degrees. The size 14 could easily have lifted an end-fed of wire much weightier than the 20AWG line which I used. On that same day, the size 24 pulled quite hard indeed. Quite easily it maintained a very taut line with no visible catenary even while lifting a center-fed dipole together with heavy dual-core unun/CMC, the latter trailing RG8X. LINK 18-sec video.
Power Sled kites pack up as shown below, their drogue chutes performing double-duty as carry bags. Note the flattened-out shape. The sled kite design includes thin, semi-rigid, fore-and-aft stays. Inside the bag, these are bent into a U-shape.
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Power Sled kites are not the only kind with good lift. Here are some others, along with the caveats for why I did not choose them.
Reputedly the best kite design for very light winds. Flies at a nicely steep line angle. Built on four long rigid members, however, this one might pose an issue for airline travel. Even so, I still kind of want one of these, could I but find one for sale anyplace other than China.
A triangular box kite with side wings. Designed by guess who for hoisting cameras and antenna wires aloft.
Research these keyword groups: Kite Arial Photograpy; and Man Lifting Kite. Others trusting their cameras and lives to a kite marks it in my book as probably a good design. Most, however, have long rigid members. And so require assembly on-site.
Having echewed the SOTAbeam offering, I was needing to fill out the rest of the kit.
The PowerSled 14 came packaged with line on a spool. Larger PowerSled kites come without. In any case, what’s wanted is braided Dacron line. Not Kevlar for several reasons. I bought two 500-foot spools: 300-lbs test for the PowerSled 24; and 500-lbs for the PowerSled 36.
Kite line yo-yo hoops work very well. But as the big kite will pull very hard, for it I puchased a reel. Kite line yo-yo hoops serve also for wire.
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Of greatest possible convenience for hoisting up a temporary end-fed or grounded monopole would be a reel of flexible bare wire spooled out to precise, resonant length for any frequency sub-band of choice. Beware, however, that said convenience must be weighed against the twin hazards of potential RF burn and much increased wind-generated static.
Still, even so, others have chosen this very thing. I have seen it in at least one YouTube video. That particular operator made use of braided, stainless steel fishing line. When I went shopping on-line for same, I stumbled upon an amazing thing. There exists deep sea trolling line made of pure copper!
Note my particular choice of reel. This was a most lucky find. Fly casting reels have a large diameter hub, thus to avoid too tightly winding the line. Very few of those, however, come also with a traversing guide. I might have preferred one with greater capacity, but not against the trade-off of losing either of those two features.
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Not shown in the photos above (since I did not think of it until after) is the use of 1/2-inch wide, large diameter rubber bands. I have bought black ones, these being advertised as immune to UV. One of these is now stretched around each of my yo-yo spools. This as prevention against the contents accidentally unspooling into a loose, tangled mess. The rubber band moves itself out of the way when unspooling. It need not necessarily be removed and reinstalled depending on how much line or wire needs re-winding back onto the spool.
Lulls and gusts of wind result in shocks to the line. A bungee cord or tension spring is thus recommended for kites with strong pull. A stout bungee for the kite line, a ligher one for the antenna. I purchased nylon shock cord, 1/8 inch OD, 25 feet in length, from which I made both. Eleven loops through 1-inch stainless steel rings for the kite line; the remainder with turk’s head knots (to be gripped by lark’s head knots) for the antenna’s peak.
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Many report success employing cork-screw dog leash anchors. I wanted something just a bit more: GroundGrabba brand, their mid-size model GR13, listed for hard ground & sand. A set of four, with closed hooks.
Why so stout? Because of a planned return trip to South Africa. A compromise between sandy beaches and rocky ground at the Cape of Good Hope.
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Here are a few very worth learning by heart. Find step-by-step knot-tying videos on YouTube. Practice on a short length of rope.
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A lark’s head is a slip-loop which holds extremely well, but only while under tension. Provide the lark’s head full slack, and nearly it falls apart by itself. Undoing and switch-over are thereby made easy. Use it to join one line to a second which itself terminates in some kind of stopper knot. The lark’s head, tied once, is not easily forgotten
Simplest is the Ashley stopper. Great for terminating the frayed end of slippery Dacron kite line. Reputedly big enough for a lark’s head to hold captive. The more complicated turk’s head, however, inspires maximum conficence.
Tie this one anywhere along the kite line, no matter how far both ends. Make the loop open enough to itself serve as a lark’s head. Suspend an antenna therefrom. Best to employ a shock-absorbing bungee between.
I chanced upon this little gem in a fabric store. I’d gone there for crochet hooks smaller than the set already owned. No better tool for fishing single conductors from out of wire-wrap backplanes and cable raceways. This one combines a knitting needle as well, useful as a marlinspike. Perfect for undoing tightly cinched kite-string knots!
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The SotaBeams kite kit comes with a 470k Ohm bleeder resistor. Fairly good protection that. Much better, however, are PolyPhaser DC Blocked protectors. With one of these, no slow voltage build up from wind driven rain, snow or dust will get to the equipment at all. As the protector reaches threshold for turn-on in a dc blocked circuit, it will go into a momentary soft turn-on as the gas barely ionizes and bleeds the static charge to ground. This does not create noise since it will not get to the arc mode and lasts only short time.
I have had a PolyPhaser unit installed at my home shack now for about eight years. Presently, that antenna is configured as a fully closed loop, one side of which is grounded, so that static is probably not an issue. For most of its life, though, that loop was open at the near corner. So for six of those years, it had most likely been a monster-sized static collector. And in all that time, never has there been an issue. This despite living one mile inland from Lake Michigan’s leeward shore, with lightning rich squall lines rolling in one after the other each spring and fall.
The thought of exposing both my RGO One and also my Rig Expert analyzer to staic simply appals. Peace of mind is well worth the extra expense while operating portable also. The further precaution of, say a 1M Ohm Ohm (vs 470k) bleeder resistor, thus to extend life of the not-so-cheap PolyPhaser I may add as well.
Possibly these are overkill. Optional items for a guy-tethered quad loop. Hand fabricated from 1/4-inch OD stainless tubing. Sized large because of already owning a quantity of size #10 AWG, counter-wound, multi-strand aluminum cable. Said very expensive wire was purchased originally for a phased array of two 3-aperture skeleton slots which is now never to be. Now it might serve instead for a kite-hoisted, 40-meter (even an 80-meter) quad loop. For being non-insulated, however, the RF burn hazard precludes any use below three meters above ground.
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Corner guides allow for smooth bends at quad corners avoiding stress risers as would cause fatigue failures from bend-reversals while flapping in the wind. Each tube shaped with a bender, all flared at both ends. Three with TIG-welded eyes saw-cut from stainless lock washers for the top and side corners. Two bent at 45 degrees for the bottom (feed point) corner.
Feed point pair fabricated in a vice by lashing together with Kevlar twine Boy Scout fashion: windings alternating between figure-eights and circumferential. Into the voids between lashings (held taut by the vice) I next mooshed several metric dollops of UV-resistant marine grade epoxy. I finished by slathering yet more epoxy on top. Distinctly unpretty, but I'm confident it will hold.
Being a former test engineer in fatigue and durability test labs, I may have over-designed this precaution by a small margin. For less expensive, smaller gage wire, 3D-printed plastic variants are recommended.
FAA has ruglations applicable to both baloons above a certain gas volume and also kites weighing more than five pounds. Not even the Mega PowerSled 81 weighs so much. Others must do so, however, or else why the rule? Anyhow, it is well to be aware.
Section 101.13 forbids the operation of a moored balloon or kite (i) less than 500 feet from the base of any cloud, (ii) more than 500 feet above the surface of the earth, (iii) from an area where the ground visibility is less than three miles, or (iv) within five miles of the boundary of any airport.
Section 101.17 further requires that the kite’s mooring lines have colored pennants or streamers attached at not more than 50 foot intervals beginning at 150 feet above the surface of the earth and visible for at least one mile.
Yet another special-purpose calucaltor coded in LabVIEW. Free, of course, like all of my priors. Output is an SVG image, all measurments shown to scale, together with all other relevant factors.
Download Link: LabVIEW_KLA.zip
A totally free, fully functional, version of LabVIEW for non-commercial purposes. You need this to run the calculator, version 2023 or newer. Now that it’s free, no longer do I build applicaions for the LabVIEW run-time engine.
Software Link: LabVIEW CE
If the SVG format is inconvenient, another free program exists for displaying, editing, and exporting to other formats.
Software Link: Inkscape
If a quad loop seems like too much work, perhaps then one of these instead...
A PowerSled 24 in good wind can lift this entire, complete with balun at center trailing RG8X coax.
Proof: Cape Point ☜ Photos and video from 2024-02-03 in South Africa. Site was the parking lot of a poplular kite-surfing beach not far from the famous upper and lower lighthouses on the Cape of Good Hope.
This idea leaps also to mind. Vertically polarized but still directional. Azimuth-steered by means of low-tension side-guys to prevent twisting in the wind.
Also known as a hair pin antenna. Fed at the bottom, no side-guys would be required. Fully grounded, bleed resistors are wholly redundant. Stake out radials on the ground. Tune it for a single band via feed-point capacitor.
Tune it instead through plural bands by varying total length. No tuning capacitor required. Employ a plastic clothesline pully up top. Use non-insulated wire pulled a grounded metal guide tube at bottom. Wind the excess onto a kite-line or cast-fishing reel. For RF-burn safety, guide the bare wire through insulated tubing up to a height just beyond reach.
Hoist aloft the middle corner. Ground the far end with a non-inductive, high-Watt, 600-Ohm resistor. Feed at the nearer, ground-level end through a 12:1 unun.
Such resistors being difficult to find, substitute with equal-ratio, high-impedance ununs at both ends. Connect transceiver to one unun, a 50-Ohm dummy load the other. Reverse direction simply by trading those two locations.
As mentioned for the half-rhombic, a wire of any convenient geometric shape may be broad-banded by using paired transformers. At both the near and far ends employ a balun or unun (as apporpriate for type of antenna). The nearer transformer to step impedance up fairly high. Wire the further transformer in reverse to step impedance back down. Connect the further transformer into a 50-Ohm dummy load. The cost, of course, is inefficiency through heating.
Latin for “Let the moocher beware”. I designed this for me, and use it with glee. I share the plans with you for free, but offered without even so much as the smell of a dead warrantee (or wheriot, as the case may be). Whatsoever disasters of cosmic proportion as may result from the use of these plans, any and all culpability rests wholly and solely with the user.
