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Posted: 11/25/2015 12:34:07 PM EDT
Allow me to ballpark engineer a 5/8ths wave 160m vertical supported by tethered weather balloons...
For some of my calculations I'll simply ask google....

Radiator length
http://www.qsl.net/w4sat/five8th.htm
585 / 1.8mhz = 325ft length of vertical radiator

I would like 3 elevated ground radials at 120 degree intervals sooo...
325ft ground * 3 + 325ft vertical = 1300ft of wire required

Lets use 18 gauge bare copper wire for everything. Goggle says 18awg weighs 4.917lbs per 1000ft
(4.917lbs / 1000ft) * 325ft = 1.598025lbs vertical

google says
1.598025lbs = 725 grams
This will be important later...


The balloon should have 3 tethers to keep it somewhat centered above the radial field.
Use Pythagorean theorem to calculate how much guy wire length we need...

sqrt(325ft high^2 + 325ft wide^2) = 460ft * 3 guys = 1380ft of guy wire

Use fishing line because its lightweight
6lbs of fishing line per 900 yards (per amazon)
(6lbs / (900yd * 3ft/yd)) * 1380ft = 3.1lbs

google says
3.1lbs = 1406 grams


725g wire weight + 1406g guy weight = 2131g payload weight

Some site found via google says 1 cubic ft of helium lifts about 28g so...

2131g / 28g/cuft = ~76cuft of helium required

Google says the volume of a sphere thats 76cuft = 5.26ft diameter balloon

Weather balloon sizes are easily available up to 30ft if needed. 8ft seems to be common enough

Grab a 125cuft to 150cuft helium cylinder at the local airgas or welding shop and we can send up our payload + any little LED  lights and radar reflectors to let the planes know we're there



Only thing that I'm wondering about is with a 325ft radial field can we run our radios close to the center or do I need 325+ft of coax to get away from the entire antenna?
Link Posted: 11/25/2015 12:44:21 PM EDT
[#1]
Saw it done at field day a few years ago - not crazy at all


enjoy!
Link Posted: 11/25/2015 12:45:03 PM EDT
[#2]
Don't forget about the FEDS.
Link Posted: 11/25/2015 12:51:51 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Don't forget about the FEDS.
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View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Don't forget about the FEDS.




Subpart B—Moored Balloons and Kites
Source: Docket No. 1580, 28 FR 6722, June 29, 1963, unless otherwise noted.

§101.11   Applicability.
This subpart applies to the operation of moored balloons and kites. However, a person operating a moored balloon or kite within a restricted area must comply only with §101.19 and with additional limitations imposed by the using or controlling agency, as appropriate.

§101.13   Operating limitations.
(a) Except as provided in paragraph (b) of this section, no person may operate a moored balloon or kite—

(1) Less than 500 feet from the base of any cloud;

(2) More than 500 feet above the surface of the earth;

(3) From an area where the ground visibility is less than three miles; or

(4) Within five miles of the boundary of any airport.

(b) Paragraph (a) of this section does not apply to the operation of a balloon or kite below the top of any structure and within 250 feet of it, if that shielded operation does not obscure any lighting on the structure.

§101.15   Notice requirements.
No person may operate an unshielded moored balloon or kite more than 150 feet above the surface of the earth unless, at least 24 hours before beginning the operation, he gives the following information to the FAA ATC facility that is nearest to the place of intended operation:

(a) The names and addresses of the owners and operators.

(b) The size of the balloon or the size and weight of the kite.

(c) The location of the operation.

(d) The height above the surface of the earth at which the balloon or kite is to be operated.

(e) The date, time, and duration of the operation.


§101.17   Lighting and marking requirements.
(a) No person may operate a moored balloon or kite, between sunset and sunrise unless the balloon or kite, and its mooring lines, are lighted so as to give a visual warning equal to that required for obstructions to air navigation in the FAA publication “Obstruction Marking and Lighting”.

(b) No person may operate a moored balloon or kite between sunrise and sunset unless its 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.

(Sec. 6(c), Department of Transportation Act (49 U.S.C. 1655(c)))

[Doc. No. 1580, 28 FR 6722, June 29, 1963, as amended by Amdt. 101-4, 39 FR 22252, June 21, 1974]


§101.19   Rapid deflation device.
No person may operate a moored balloon unless it has a device that will automatically and rapidly deflate the balloon if it escapes from its moorings. If the device does not function properly, the operator shall immediately notify the nearest ATC facility of the location and time of the escape and the estimated flight path of the balloon.
Link Posted: 11/25/2015 1:12:56 PM EDT
[#4]
So apparently the balloon that the army/NSA/whomever used that got loose last month was missing a few of these requirements - especially the last one about the automatic deflation device....
Link Posted: 11/25/2015 1:22:32 PM EDT
[#5]
I fly 1000' of string on a sled kite that generates quite a bit of lift.  They are common here.  We even have a kite designers convention every year.

According to that post above, if I hang an antenna on it I'm a felon?

Nice.
Link Posted: 11/25/2015 1:23:47 PM EDT
[#6]
In order to save a little weight, use one of the 3 guy wires as the antenna itself. It would have a slight angle but I believe it would make little to no difference in the performance.
Link Posted: 11/25/2015 1:28:30 PM EDT
[#7]
Ah... It seems those rules only apply if you go over certain size or create a hazard.
Link Posted: 11/25/2015 1:41:32 PM EDT
[#8]
You could skip the guy wires and just use one thin copper clad steel wire.  Let it drift.  Electrically it's balanced and centered at the feed point.  Not as ideal but it will save a lot of weight.

Yes, you can sit within the field, if you have sufficient radials.  Although underneath the elevated radials is best if possible.
Ground rod in the center is probably a good idea.
Link Posted: 11/25/2015 1:42:30 PM EDT
[#9]
Don't forget to add in the weight of the balloon, too. However an 8' balloon will be plenty big enough for your project. I wouldn't get to jazzed up about FAA reg's but if you decide to meet the letter of the law you'll want to call the local FSDO and chat them up well ahead of time. Once you get it all locked down with them they'll be familiar with you and every subsequent time you launch it'll be easy.

eta https://skyvector.com/ will let you find airports near you.
Link Posted: 11/25/2015 1:56:15 PM EDT
[#10]
[.....
Link Posted: 11/25/2015 2:42:46 PM EDT
[#11]
All good suggestions. The only airport I might be concerned about is just a farmer's field. Does this actually count as an airport?

https://skyvector.com/airport/VA17/Mulberry-Run-Airport


Still trying to figure out if I need to contact anyone about an 8ft tethered balloon that might be 350ft max high when the surrounding hills are 2500ft.

ETA - Looks like that answer is yes
Link Posted: 11/25/2015 2:57:29 PM EDT
[#12]
Look at the copper fishing line. Saw one a couple of years ago that used that because of the strength to weight ratio. Also look at a bleed off resistor for the amount of static that is generated on the antenna itself. There was a guy that received the shock of his life when he went to connect the coax and grabbed the antenna and the built up static discharged through him.
Link Posted: 11/25/2015 3:04:35 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Look at the copper fishing line. Saw one a couple of years ago that used that because of the strength to weight ratio. Also look at a bleed off resistor for the amount of static that is generated on the antenna itself. There was a guy that received the shock of his life when he went to connect the coax and grabbed the antenna and the built up static discharged through him.
View Quote



Good idea. I will attach a lightning arrestor to it that shunts DC/static to ground but allows AC to pass.
Link Posted: 11/25/2015 3:32:42 PM EDT
[#14]
Have you priced out helium? I heard it's in short supply.
Link Posted: 11/25/2015 4:16:41 PM EDT
[#15]
use hydrogen.

then you can clean up quickly afterward.

poof!

'monkey
Link Posted: 11/25/2015 4:40:09 PM EDT
[#16]
The W6TRW club in Redondo Beach, CA does exactly this! They have an aerostat which they run up for the 80 and 160 meter contests. Give them an Email.

eta
Some site found via google says 1 cubic ft of helium lifts about 28g so...
View Quote



I researched this some years ago. 1 cu. ft. of helium per ounce, at 70 degrees F, at sea level was the answer I got.
Link Posted: 11/25/2015 7:00:36 PM EDT
[#17]
Why are you going with 5/8 instead of 1/4 wave?  Everything reliable that I've read tells me that the 1/4 will be better.

ETA:  One source:  http://topband.contesting.narkive.com/73Bhg2sW/topband-1-4-1-2-or-5-8-wire-vertical-which-to-use

I remember this thread:  https://www.ar15.com/archive/topic.html?b=10&f=22&t=669530
Link Posted: 11/25/2015 8:49:24 PM EDT
[#18]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
All good suggestions. The only airport I might be concerned about is just a farmer's field. Does this actually count as an airport?

https://skyvector.com/airport/VA17/Mulberry-Run-Airport
View Quote

It does, however since it is not a public use airport the FSDO is probably going to give you leeway, again assuming you actually go through the entire notification thing. If you do then all the FSDO will probably have you do is communicate with the airport owner.
Link Posted: 11/25/2015 10:13:03 PM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
The W6TRW club in Redondo Beach, CA does exactly this! They have an aerostat which they run up for the 80 and 160 meter contests. Give them an Email.

eta



I researched this some years ago. 1 cu. ft. of helium per ounce, at 70 degrees F, at sea level was the answer I got.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
The W6TRW club in Redondo Beach, CA does exactly this! They have an aerostat which they run up for the 80 and 160 meter contests. Give them an Email.

eta
Some site found via google says 1 cubic ft of helium lifts about 28g so...



I researched this some years ago. 1 cu. ft. of helium per ounce, at 70 degrees F, at sea level was the answer I got.


1 ounce = 28.3 grams so very close. I think the site I saw said 28.2g. I try to be conservative in my numbers.



Quoted:
Why are you going with 5/8 instead of 1/4 wave?  Everything reliable that I've read tells me that the 1/4 will be better.

ETA:  One source:  http://topband.contesting.narkive.com/73Bhg2sW/topband-1-4-1-2-or-5-8-wire-vertical-which-to-use

I remember this thread:  https://www.ar15.com/archive/topic.html?b=10&f=22&t=669530


Interesting points. Some of the material I read said 5/8ths would provide the highest gain and best takeoff angle combination. I will read over you material and take it under advisement. Being that the center is adjustable theres no reason we couldn't crank it down to quarter wave and try it unless the radial length would also need adjustment. I'm not the smartest guy on the block so you tell me



I know I'm not the first guy to come up with the idea to do this. If I were able to do this a few thousand feet higher up on a mountain would that provide further benefit? Skyline drive its just around the corner from me and I can always ask if I can do it up there


Link Posted: 11/25/2015 10:55:40 PM EDT
[#20]
I would run the numbers on 16ga aluminum electric fence wire. It's cheap in 1/4 mile spools and much lighter and stronger than copper.
Link Posted: 11/25/2015 11:07:16 PM EDT
[#21]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Interesting points. Some of the material I read said 5/8ths would provide the highest gain and best takeoff angle combination. I will read over you material and take it under advisement. Being that the center is adjustable theres no reason we couldn't crank it down to quarter wave and try it unless the radial length would also need adjustment. I'm not the smartest guy on the block so you tell me
View Quote


My basic understanding is that a 5/8 will only achieve a lower take-off angle and have 3dB gain over 1/4 when surrounded by a perfect ground plane extending well into the far field, like salt water or a copper plate extending for miles in all directions.  In the real world 1/4 wave is better whether elevated or ground mounted.  There are other things that make a 5/8 less desirable too.  ETA:  In your case, height and weight for sure.  
Link Posted: 11/26/2015 10:48:19 AM EDT
[#22]
I suggest looking into a ground mounted half wave length vertical instead.  According to the author, "a single ground rod will often suffice for a ground system to complete the circuit since very little current has to flow through this ground system".



Note that the antenna is DC grounded through the transformer, and the transceiver isn't directly coupled to the antenna.
Link Posted: 11/26/2015 5:37:22 PM EDT
[#23]
"... one thousand ..."  

Second's up.  You're crazy again.

Link Posted: 11/26/2015 11:10:57 PM EDT
[#24]
p
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I suggest looking into a ground mounted half wave length vertical instead.  According to the author, "a single ground rod will often suffice for a ground system to complete the circuit since very little current has to flow through this ground system".



Note that the antenna is DC grounded through the transformer, and the transceiver isn't directly coupled to the antenna.
View Quote


+1000


I've wanted to do something like this for a long time.

Years ago, when I got out of the Army, I ended up on a hot air balloon team.
We talked about stuff like this, but never tried it.

...probably because flying is fun enough

You want that thing grounded to protect your ass and your rig from static discharge

Link Posted: 11/27/2015 12:51:39 AM EDT
[#25]
Any ground mounted vertical will have significant ground losses without a ground plane, regardless of whether it's a 1/4, 1/2 or 5/8 wave.
Link Posted: 11/27/2015 11:55:11 AM EDT
[#26]
I did this when I was in the outer banks a couple years ago, just with a kite. I'm pretty sure aa874928379423-2 and I spoke like there was no distance between us at all.

I like the idea.
Link Posted: 11/27/2015 12:10:12 PM EDT
[#27]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Any ground mounted vertical will have significant ground losses will not work without a ground plane, regardless of whether it's a 1/4, 1/2 or 5/8 wave.
View Quote



Also it would not be safe to be near the antenna/radio without sufficient radials.  You would be the counterpoise for all the current.
Link Posted: 11/27/2015 1:50:27 PM EDT
[#28]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Any ground mounted vertical will have significant ground losses without a ground plane, regardless of whether it's a 1/4, 1/2 or 5/8 wave.
View Quote

A good counterpoise is far more critical with current-fed antennas such as a 1/4-wave or 5/8-wave.  It's far less critical with voltage-fed antennas such as a 1/2-wave.  A 1/2-wave antenna will certainly benefit from a good counterpoise of course...
Link Posted: 11/27/2015 8:26:18 PM EDT
[#29]
Make sure their is always a bigger, better and more direct counterpoise; than the bag of salt water wearing headphones.  If you, as a bag of salt water, are the best counterpoise available you may experience some electromagnetic thermal heating as the current passes through you the bag of salt water to the other end of the antenna.

ETA, this is exactly how your microwave heats up the soup for lunch.  Power wasted as heat instead of radiating.
Link Posted: 11/27/2015 8:34:11 PM EDT
[#30]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I did this when I was in the outer banks a couple years ago, just with a kite. I'm pretty sure aa874928379423-2 and I spoke like there was no distance between us at all.

I like the idea.
View Quote

That kite antenna kicked ass!
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