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Author Topic: long wire ballon antenna?  (Read 1236 times)
KC5UUS
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Posts: 103




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« on: May 15, 2009, 09:47:23 AM »

I guess the question fits here as well as any forum.
 Ok i wanna get a wire up in the air for 75 mtrs. i mean i wanna get it up way up ha. Ne way how feasible is it to use a ballon for a long wire? has any one had any real experience with this? doesnt seem that hard. does someone know of a web site pertaining to this. suppose i will google it. but would like to hear from some hams who have done this thanks.
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WW5AA
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Posts: 2086




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« Reply #1 on: May 15, 2009, 12:34:24 PM »

How high are you planning to go. The main consideration is a radial field. If within five miles of an airport there are restrictions. The size of the
baloon and height will determine if you need to notify the FAA. Insurance? These are probably above and beyond what you are planning but it's always better to be save and not sorry. I have done this at field day years ago and for the most part the effort is not worth it.

73 de Lindy  
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W0FM
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Posts: 2055




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« Reply #2 on: May 15, 2009, 02:50:11 PM »

Also, be aware of the height of the wire with regard to power lines in the vicinity.  
Even a slight breeze can move the ballon off of the vertical axis.  If the baloon bursts and the antenna wire drops onto a power line, it will NOT be a good day for playing radio.

Be safe.

Terry, WØFM
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WB2WIK
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Posts: 20595




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« Reply #3 on: May 15, 2009, 03:32:08 PM »

Unless the day is absolutely "dead calm" with wind speeds of 0.00 mph (which occurs just about never), a balloon cannot support a wire antenna with much elevation above ground because even a 1 mph gentle breeze will blow it far off course.  Then, instead of a vertical wire, you have a slanting wire, and with a tiny bit more breeze, you have a horizontal wire laying on the ground.

"Back guying" it doesn't work, it only makes the antenna fall lower, faster.

A couple of things that work better are a kitoon, which is 1/2 kite 1/2 balloon, so when the wind blows it actually tends to *raise* the antenna (kite properties) rather than lower it.  Only problem with this is they're expensive.  I bought a kitoon from a local place that made banners for car dealers and such and they charged $149 for a fairly small one.

Another thing that works better than a ballon is a whole lot of balloons that are smaller than a single large one would be for equivalent lift, and you tie them all along the antenna wire at maybe 5-10 foot intervals from bottom to top.  This distributes the lift and the wind drag and actually does hold the wire more vertically than a larger balloon at the top: I've tried it, and that's the way it works.  But then, you need maybe 20-30 balloons, each filled with Helium, and each tied off to the antenna.  It's a time consuming installation, can easily take a couple of hours to do that.

Of course, any Helium balloon doesn't hold the gas for very long, so these are all "temporary" antennas.  You're lucky if one will make it through a weekend.

WB2WIK/6
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W5RB
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Posts: 564




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« Reply #4 on: May 15, 2009, 03:39:01 PM »

Here are a couple of links to get started. I was thinking K1TTT had something on this as well, but can't find it with a cursory look. You WILL need a bleeder resistor to keep static from being a problem.Also, I see you live very near an airport.This presents its own issues, if you plan to use it at home. Be safe.

Russ, W5RB

http://deloach.net/balloons.html

http://www.hard-core-dx.com/nordicdx/antenna/special/baloon.html
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KC5UUS
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Posts: 103




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« Reply #5 on: May 16, 2009, 10:47:49 AM »

yea i live pretty close to wiley post airport, and well really sounds like it really isnt gonna b worth all the trouble. and the wind is friggin nuts most of the time here in okla. dunno what i was thinkin hihi. the ole pecan tree will  just have to suffice for  my antenna, thanks guys
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WX7G
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Posts: 6039




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« Reply #6 on: May 20, 2009, 06:53:04 PM »

Are you ready for a real answer?

I regularly fly balloon verticals. I use a 36" balloon inflated with helium to a diameter of 30". It will lift 4 oz. I use The Wireman #26 copper clad multistrand steel wire. It weighs 1 lb per 1000'.

With no wind the ballon easily hoists a 130' wire. In a 10 mph wind two balloons are needed - one at the halfway point - to keep it above a 30 deg angle.

For 75 meters a quarter wave wire will work well. A halfwave wire will be better if the GND is not good, and need no ground other than a short ground rod or a few short radials. The input impedance is around 2000 ohms. A tuner may work or use a parallel LC tapped for 50 ohms. Make the Xc and Xl about 500 ohms.

Taller vertical wires will not work any better for low angle (DX) work.
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