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Author Topic: end fed wire plus helium baloon  (Read 1635 times)
TTOMAS59
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« on: November 27, 2012, 06:54:09 PM »

Has anyone used a helium baloon to launch an end fed wire. From what I've read a helium baloon will stay aloft 4-7 hours. 100 ft of 22 gauge should weigh less than a pound. The question then becomes what size diameter baloon is required to lift the wire 100 feet. Also, if not in an urban area the height restriction may be 250 feet. Think of the possibilities for field day!
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ONAIR
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« Reply #1 on: November 27, 2012, 07:05:43 PM »

Been tried many times before!  The results can be good if you are in an area with low wind speeds.
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TTOMAS59
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« Reply #2 on: November 27, 2012, 07:06:57 PM »

YRE: On fleabay a 36 inch weather baloon is $15 plus shipping.
Helium tanks on Amazon are $40 for 30 cubic foot. Correction: the FAA height restriction for marked antennas is 2000 ft. Get's one to thinking.
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TTOMAS59
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« Reply #3 on: November 27, 2012, 07:11:13 PM »

My best wire antenna is a 70ft end fed with a 9:1 unun up 50ft.
Another 150 ft and would probably work well.
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WB6BYU
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« Reply #4 on: November 27, 2012, 07:26:48 PM »

Weather balloons work when there is NO wind.  It doesn't take much to tilt the
antenna 45 degrees or more, and sometimes pretty close to the ground.
A kite is better when the wind is up.  A "kytoon" handles both situations - those
are the blimp-shaped balloons used at car dealers, etc.

My suggestion is that you use a strong string to tether the balloon rather than
relying on the wire to do so:  copper isn't very strong for the weight, and a
strong string with a light wire is better than either a strong wire (heavy) or
the light wire alone (too weak if the wind comes up.)

For reference, #22 insulated copper wire is about 2 pounds / 1000 feet.


Also, making a wire antenna longer doesn't necessarily improve performance.
A 50' wire may be longer than optimum on the higher HF bands, depending
on the optimum vertical angle of radiation to your target.  150' gives pretty
good performance on 80m when it is straight up, but may be no better on 20m
than a 30' wire.  When the wire is at an angle (as it often is if there is any
wind) you have to consider the directional properties, which vary with the
wire length in wavelengths and the angle of the wire with respect to the
ground.
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WX7G
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« Reply #5 on: November 28, 2012, 07:44:36 AM »

I have done this many times and will do it again this weekend for the ARRL 160 meter contest. I will be flying a 100' base loaded wire over The Great Salt Lake of Utah.

To loft 130' of #26 AWG copper weld wire (The Wireman sells this) a 36" balloon filled to 32" works and it will fly for about two days. One balloon every 60' is even better. Party stores sell 36" balloons for $3.

Much wind at all and it will fly horizontal, so it's good to fly it from a mast so that it turns into an inverted-L in the wind. The input impedance will drop and a tuner at the radio can be used to keep the radio happy. And any snow at all will collect on the balloon and bring it down. And bring extra helium and extra balloons. I have had them lose gas and they can pop while handling them. This weekend I'm bringing four balloons and four disposable tanks of helium (that's about $40 to loft one balloon). With the helium shortage the place I had been renting a helium tank from is not renting them at this time.

A small advertising blimp would be even better because the wind will cause them to fly rather than blow down. But with the unavailability of helium at this time a simple balloon is the way to go. 
« Last Edit: November 28, 2012, 08:06:38 AM by WX7G » Logged
WB2WIK
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« Reply #6 on: November 28, 2012, 09:21:42 AM »

I've done this also, always with a "group" (multi-op contest situation, such as the 160m contest) to make it easier.

We tried a lot of stuff.  A BIG latex helium balloon will lift a very long wire straight up vertically, but as stated, only with ZERO wind.  The tiniest puff of wind blows it far off course and a stiff breeze can blow it down almost to the ground.

What we found was a long string of smaller helium balloons works better.  Never tried to calculate exactly why, this was all just trial-and-error, with quite a few errors.  Plus it's fun filling up helium balloons, as you can take a lungful and then talk funny for a minute or so. Cheesy

But what seemed to work well was about 6-8-10 smallish balloons (maybe 12" or so each), tied every 10-20 feet along the wire, so the "lowest" one was just out of reach, and the "highest" one was at the very top.  Seemed less effected by the wind, and the balloons are cheaper. Wink
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K3GM
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« Reply #7 on: November 29, 2012, 05:09:30 AM »

My experience using tethered balloons over the years for Field Day ops is that latex weather balloons perform poorly.  A slight breeze flattens the windward side of the balloon increasing its area and forcing the balloon downward on its tether.

What works is a "barrage" style balloon.  You'll often find these tethered at car dealerships advertising "special sales".  The blimp shape and fins point the nose of it into the wind, and it doesn't flatten out as round balloons do.  Our club's balloon was obtained off the internet.
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N8YB
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« Reply #8 on: November 30, 2012, 12:57:05 PM »

The lifting ability of helium varies with temperature, pressure and humidity.  A good estimate would be 60 lbs of lift for 1000 cubic feet of gas.  A little math and you get 1 pound of lift for just under 17 cubic feet of gas.  Keep in mind you need to add the weight of the balloon in your calculations. 

73 de Jerry N8YB
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W5WSS
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« Reply #9 on: December 02, 2012, 06:02:46 AM »

I have used a Helium filled balloon.

We actually succeeded in a multi band doublet for 160 and up.

Sort of inverted

fed with 300 ohm balanced line.

Used it on Field day 2005, the ends tethered with lightweight twine.

See photos at TRO repeater club of which I am not a member.

I loaned them my wide range tuner otherwise they would not have been able to use 160m.

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