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Combining the kite and balloon.

Photo 1
The "Kytoon" in action. The combined balloon and kite action ensures proper flight under varying wind conditions and keeps the antenna more nearly vertical than is ordinarily possible with either a kite or balloon.

Most amateurs at one time or another have dreamed of owning skyhooks to support their antennas. Very little amateur work has been done with balloon- or kite-supported antennas - at least the only published reports are articles in QST for April and November, 1940, describing the use of meteorological sounding balloons and kites as supports for antennas. While both methods achieved moderate success, many shortcomings were self-evident.

Balloons and kites were supplied with the Gibson Girl life-raft transmitter during the war for carrying antennas, but again the balloons and kites had serious drawbacks. Balloon-supported antennas tended to be blown down into the water or toward the ground in high winds, and the kites could not be flown without a wind. Satisfactory performance was possible only over a very narrow wind-velocity range with either.

The Kytoon(1) which we used in the recent Field-Day Contest is an air-foil balloon which flies partly on the principle of a balloon and partly on the principle of a kite, and thus incorporates the good qualities of both. It is inflated with hydrogen or helium and, in a dead calm, exerts its lifting force as does a balloon because it is lighter than air. As soon as the wind rises, kite action exerts an upward pressure on the air foils, increasing the lifting ability of the Kytoon by three or four times that of the free-balloon lift alone.

The construction of the Kytoon is illustrated by the accompanying photograph and Fig. 1. It is 6½ feet long and 39 inches in diameter, tear drop in shape. The casing is made of light, strong Nylon fabric which encloses a specially-shaped bladder or balloon made from Neoprene. The foil wings are made of a lightweight cotton balloon cloth and are supported by aluminum-alloy struts which fit into sockets on an aluminum spider at the stern of the Kytoon. The filling valve projects through a hole in this spider. The Kytoon itself weighs 1.62 lbs., and when folded can be carried in a package 14 inches long and 3 inches in diameter. No special claims as to lightweight portability are made because the separate cylinder for charging the balloon weighs in the vicinity of 25 pounds.

Fig 1
Fig. 1. Outline sketch of the Kytoon. The length is 6 ft. 6 in., diameter 3 ft. 3 in., and wingspread 4 ft. 3 in.
Labeled parts are as follows: A, casing; B, Neoprene bladder; C, wings; D, wing struts; E, flying bridle; F, rubber band to allow stem to rise in a strong wind; G, flying line.

Filled with hydrogen under a pressure of 4 inches of water, the Kytoon has a volume of 40 cubic feet, and a net (or free) lifting force in a dead calm of 1.23 lbs. In a 3-m.p.h. wind, the lifting force is increased by the action of the air foils so that it will carry a net load of 2.6 lbs. Under these or more favorable conditions of load, and wind velocity, the angle with the horizontal at which the Kytoon flies is never less than 45°. The objections to kites and spherical balloons are thereby overcome. The substitution of helium for hydrogen results in reduction of the free lift by about 10 per cent.

During the recent Field-Day Contest, a Kytoon was used by the authors at W1LLX/1, Winchester, Mass., with a vertical antenna 132 feet high (No. 18 enameled copper wire), and at W9RCQ/1 at Wayland, Mass., with a vertical antenna 396 feet high (No. 18 braided copper wire). Our results on 80 meters were so good that we both say that the Kytoon gave us the best 80-meter antenna we had ever used.

At W9RCQ/1, a 132-foot horizontal was used as a comparison antenna, and at distances up to 300 miles, the vertical brought much better signal reports. Both were end-fed antennas, and 25 watts was fed to the 807 final. One-hundredand-thirty-two stations were worked on 80-meter c.w. by one operator. The Kytoon flew for 30 hours with no attention throughout the contest, and stayed within 20 degrees of the vertical in winds estimated to have been 20-30 miles per hour.

The Kytoon should be a handy device for emergency transmitter set-ups, obviating the need for carrying around bulky portable antenna masts. It is, of course, tops for Field Days and should prove an interesting gadget for elevating high-frequency antennas, test instruments, and a host of other things in which amateurs and experimenters are interested. Perhaps long-wire vertical antennas can now be exploited with outstanding results.

Notes

  1. Trademark Reg. U. S. Pat. Off. Here's a new wrinkle on getting a Field Day antenna high up in the air in a hurry. This "skyhook," with its accessories, makes up a compact unit when not in use and can be conveniently transported with the rest of the gear.

D.T. Ferrier, W1LLX
W.G. Baird, W9RCQ/1.