Thursday, March 7, 2019

Get up high with a kite antenna

Kites have a long and distinguished record in radio communication. They were most famously used by Marconi for the first crossing of the Atlantic by radio in 1901.  150 years before Benjamin Franklin used one to prove the electrical nature of lightning. And the famous WWII Gibson Girl transmitter used a kite antenna to enable communications from sea.

In amateur radio a kite is the cheapest way to get great antenna height without having a massive mast, a very tall tree or your own hovering aircraft to hold a wire up. A single kite can support a vertical antenna a quarter, half or a five-eighth wavelength high. Provided you've attended to the counterpoise, this will be the closest you'll get to having a no-compromise antenna.  You will likely have the strongest signal of any station on a band like 160 metres.  The more ambitious have even been known to launch an array of kites to support even more wire, with other antenna types such as half-squares being possible.

There are a few things to think about with kite antennas. You'll need to choose a suitable kite. I've had success with a delta coyne kite. But box kites haven't been so successful for me.  It needs to be stable and big enough to carry the wire antenna's weight over a wide range of wind speeds. But it can be too big otherwise it will be unwieldy.  There's even kites especially for ham radio now made.

You will need sufficient string line to hold the kite. Don't rely on the antenna wire for this job. Kite antenna users often also have the kite much higher than the top of the antenna wire as the kite can sit in a more stable air stream.  Then there's safety. You don't want to be doing this in a thunder storm. Or even when the air is hot and moist with static. And you need to have a bleeder resistor going to earth as the static picked up could damage your receiver's front-end, even when there's no storm around.

As for a suitable antenna, I would suggest starting off with an end-fed half wavelength of wire and a small L-match antenna coupler. Or even a quarter wavelength for 160 metres.  You want to be doing this in a field where there is no one around. Extra points if you can find one with a metal fence that you can tap on to for your ground system.

It is a bit of effort. Until you've got it down pat you might find it a two person affair. One person to look after the kite, another to look after the radio operating. But you'll get some amazing results.

Read experiences and watch videos from others and me to see how it's done.

* My own experiences with kite supported antennas (also with videos)
* Wikihow article on kite antennas
* Kites for lifting antennas
* Kites FAQ from SOTABeams
* ZL2AL's notes on kite and balloon antennas
* W6KOA Kites On Air group
* KB1NTY kite antenna demonstration (video)

It's definitely all worth it. You'll get lots of exercise. So good luck!

PS: The items below may assist your experiments with kite supported antennas.  They are affiliate links meaning that I receive a small commission (at no extra cost to you) if you decide to purchase.

1 comment:

  1. This sounds like a good video, and since yours are always very educational... ;)


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