Hello,
Does anyone have experience in using affordable weather balloons to support vertical wire antennas? I’m considering such a set-up for the forthcoming Swiss National Mountain Day, which takes place on the 80m band. The idea would be to support an 80m EFHW (basically a ~40m wire with a transformer) fed by a QRP tx (KX2). It would be great to hear any tips from anyone who has tried using a tethered balloon set-up for supporting wire antennas.
Thanks in advance!
HB9HRJ
…I have noted that how it is tethered is very important; a substantial metal stake eg a long star picket into the ground is needed. Good luck with it.
Geoff vk3sq
I cannot share any experience with weather balloons but I worked with a 40 m EFHW and a 6 m² Kite. Since you mentioned a QRP TRX, I suppose you would be using a thin and light wire. In case you intend to use this wire as the only connection to the balloon, this may be dangerous. My kite was held by a separate rope of high strength for very good reason. From 3 Bft upwards it was impossible for me to hold the kite by hand and I needed a strong anchor. The separate wire was connected via a bleeder box for static discharge, which is essential to protect the TRX. I estimate that the cross section of the balloon exposed to the wind would be at least comparable to the one of my kite, maybe even higher. This may result in significant forces even with moderate wind. Just my two cents…
Good luck, Peter
Hello,
I tryed once!!! The balloon was going up and down, right and left because of the wind, so i add a kite under the ballon to keep it “vertical”… then i gave up!
Gerald F6HBI
How about these kind of contraptions? Explodes the budget but in principle? https://www.helikites.com/why-helikites
…whatever floats your boat…and you can afford!
I used to use a 55 cubic foot helium balloon shaped like a fish so it climbed into the wind, lifting 128 feet of #22 bare wire for 160 meters. It was raised by a 24 volt cable reel from an old military plane.
Elliott, K6EL
I have used a kite to hold up an end fed half wave for 160m.
It worked but needed a spare person to look after the kite, to keep the wire taught and the kite flying.
Regardless of the challenges it was a lot of fun.
73, Warren vk3byd
Kites FAQ ( Sotabeams ). Not directly relevant but lots of useful information….
The “balloon shapes like a fish” is often called a “kitoon”.
They have the advantage that they don’t lay over mostly horizontal when the wind blows, as many round baloons will.
I often see them used as advertising for businesses.
One other thing to note - you probably done this already but just in case, check national/regional legislation on how high you can raise the balloon.
Example, in Ireland there is the statutory instrument for Tethered Balloons, Airships, Free Balloons and Kites. Link below:
TL;DR summarised by Grok 4.3:
Basically: ask first, stay low, stay safe, and don’t fly near airports or at night without permission.
Thanks for reminding me I have an unopened box kite I still want to put on the air with a Chameleon LEFS 8010 EFRW. 
Thanks to everyone for your responses, all are very helpful!
It appears that the smallest 0.15 m³ Helikite may do the job if I use very fine copper wire (the sort sold on reels for fly tying) taped to the Dyneema line. However, the lightest wire I’ve come across marketed for amateur radio is DX-Wire UL at around 4 g/m. That would result in 40m x 4g/m=160g, which is above the carrying weight of this Helikite version (60g no wind, 180g with 15km/h wind).
Has anyone used the two wires? Is there a good reason to use DX-Wire UL if the Dyneema is carrying all the mechanical load?
Thanks in advance!
As a long-time user of Poly-STEALTH-26 antenna wire for lightweight wire antennas, I would probably explore the possibility of creating the lightest possible overall system, for which POLYS-22 would suffice.
- Break strength: 31.75 kg
- Weight: 3.42 g/m
- Diameter: 1.32 mm (19 x 0.16 mm)
EDIT Sorry, I overlooked this: “Is there a good reason to use DX-Wire UL if the Dyneema carries the entire mechanical load?”
If so, POLYS-26 would of course suffice (weight 0.57 g/m → 22.6 g/40 m).
Thanks Heinz. I’m having trouble replicating the maths though?
| Type | Weight (lb/ft) | Weight (g/m) | Break (lb) | Break (kg) |
|---|---|---|---|---|
| 22 AWG PS | 0,0145 | 21,58 | 170 | 77,1 |
| 26 AWG PS | 0,0065 | 9,67 | 92 | 41,7 |
| Conversion factors | ||||
| g/lb | 453,592 | |||
| m/ft | 0,3048 |
For example, the 22 AWG advertises as 14.5lbs per 1000 feet.
14.5lbs x 453.592 g/lbs = 6577.084g
1000 ft x 0.0348 m/ft = 304.8m
6577.084g / 304.8m = 21.58 g/m, no?
The DX-Wire UL wire advertises 4 g/m and break 60kg.
That depends entirely on which data we are both working with, hi; see POLYS wire specs
POLYS-26: 0.38 lb/1000 ft, break strength 92 lb
0.38 lb/1000 ft → (0.38/1000)(1/0.3048)=0.00125 lb/m → 0.567 g/m (~22.7 g/40 m)
POLYS-22: 2.3 lb/1000 ft, break strength 170 lb
2.3 lb/1000 ft → (2.3/1000)(1/0.3048)=0.00755 lb/m → 3.425 g/m (~137 g/40 m)
I took the specs from the website you provided:
Now, I also looked at what appears to be the manufacturers site (?) which gives the same weight (lbs/1000ft) as yours but not the same break:
There is a big difference 
This was my original supplier, but unfortunately, they’ve been out of the online shop for some time now. Take a look at their specs, too …
So the question remains: which specs are actually correct? Are they the ones used by Davis RF for over 40 years, or those published by current vendors?
For portable wire antennas, the breaking strength of the POLYS antenna wires (copper-plated steel wire) was never a problem.
For a balloon-borne vertical antenna, it would be easier to handle if the antenna wire could also serve as the balloon’s attachment point.
Twelve years ago, I conducted some successful experiments with a kite antenna.
The mini profoil kite had a surface area of one square meter or so and came from a toy store.
The 20-meter-long EFHW—made using UL wire from DX-Wire—was attached below the kite at the separate kit line, with the unun at the lower end followed by about 10 meters of coaxial cable.
A second ham radio operator flew the kite.
The antenna’s efficiency was remarkable, but the effort involved was quite high, so I discontinued further experiments.
I didn’t have any problems with static electricity. Using an EFHW with a 1:49 transformer makes it easy to bleed off the charge by grounding the radio.
73 Chris
We used an old weather balloon to support our 160m vertical on Field Day 2023. It worked well as antenna support.
We had around 2 kg of reserve buoyancy, which was sufficient for us. We also guyed the balloon to keep it up against the wind. I did not try without the guy wires, but I expect it would have been quite far from vertical without them at the 4-6 m/s wind we experienced. We used fishing lines for all the structural wires, both because they are fairly lightweight and because we hoped they would not soak in the rain and interfere with the antenna pattern.
We sketched up some more details and pictures in this blog post. We found this to be a very fun project, and we intend to make another attempt this year.
Thanks again to all of you for your inputs, this has been very helpful! I have decided to park this idea for the time being as there is insufficient time and too many unknowns to implement in just a few days.
@VK3SQ: thanks and it also appears that a swivel may also be a good idea to avoid the tether from getting all twisted
@F6HBI: those Helikites do appear to be more stable in strong winds, to be confirmed though https://youtu.be/-qntOAKyjco?si=uCGcDD8XZPmtcjbE
@DM7KN: being a stinge sometimes also makes the hobby more fun but I am keeping this option at the back of my mind 
@K6EL and @VK3BYD: well done! Both seem like a very interesting solutions for 160m
@G4IPB: indeed, very useful!
@WB6BYU: that’s also what I saw on the Web, tbc in the field though
@EI3LH: thanks for the warning! Looks like Swiss regulations are fairly straightforward e.g. max 60m high, no less than 3km form an airport.
@HB9BCB: I now have more time to investigate and send emails to the vendors
@DL1CR: Well done. Interesting to note that you still need a second operator to fly the kite despite that it appears to be a “sled” kite. Also that the static bled to the ground with just a wire (Sotabeams recommend adding a resistor).
