Can I use a weather balloon to improve cellular reception?

November 18, 2021 9:37 AM

I go to a remote camp house with friends who are somewhat (majorly) college football obsessed. The house is in a valley and *just* outside dependable cellular coverage. If you walk 100 yards up the drive, you can get a decent data connection. Assuming good weather, is it at all practical to use a weather balloon to lift a phone/hot spot to an altitude of 100 yards and piggyback off of that connection for about 3 hours? Assume the payload is less than 8 ounces.

I'm not looking for a guaranteed connection. Attempting the project is reward enough, assuming it's not doomed from the get-go.

posted by donpardo to Technology (14 answers total)

I don't think it's doomed from the get go. I'd start to see if you had any reception on the roof. It's not a bad idea though!

Another alternative is you put the whole up the drive, convert internet to cat 5, and run that as far as you can.
posted by bbqturtle at 9:53 AM on November 18, 2021

Best answer: I agree that a temporary run of ethernet up the drive is probably the simplest approach. Failing that I would put the hotspot at the end of the drive and use homemade directional WiFi antennas to get a signal back to the house. You're almost certainly going to have some kind of directional antenna or repeater system to get a connection from the balloon back to the ground anyway, and a directional antenna will work better without a moving target.
posted by jedicus at 10:01 AM on November 18, 2021 [3 favorites]

100 yards is - I suspect - a long way to access the hotspot's WiFi from the ground. I'd test that first to see if you even get a decent phone->PC signal at that range.

If so, a cubic foot of helium can lift about one ounce. A quick check on google says that you can buy a 14.9-cubic-foot tank of 80% helium for around $40. To lift an 8oz hotspot/battery plus the balloon itself would require at least one of these, so you're either spending at least $40 every Saturday, or using a good enough weather balloon that it can hold helium for a week or more, and storing a 15-cubic-foot balloon (about 3 feet in diameter) somewhere.
posted by Hatashran at 10:06 AM on November 18, 2021 [1 favorite]

What's the rest of the network look like? Are you just intending to connect a phone or smart TV to the wifi from the hotspot? I'd be concerned that the hotspot will be too far away to connect via wifi -- theoretical max distances vary by device, but 300 feet is likely to be at or beyond the limit even in open air. Add in the roof (assuming you're watching indoors), and the max distance will be less. Though in general, adding even a little bit of altitude (especially when outdoors) can be quite effective, so you may not need to go anywhere near that high. I agree that it would be worthwhile just getting on the roof with a long stick, taping the hotspot to the stick, and seeing if even a little bit of altitude gets good enough reception.

If you do want to try the balloon at 100 yards, I'd definitely want to verify wifi range beforehand. Go to a large field or open area, set up the hotspot at one end, start walking away, and see what distance you can connect at. That will be relatively similar to the max altitude you can use, assuming that your wifi device is outdoors during the game.
posted by yuwtze at 10:14 AM on November 18, 2021

Best answer: I agree that, technically, it should work. Legally, assuming you're in the US, a moored balloon more than 150 feet up requires FAA notice and lighting after sunset. (There may be other local restrictions too.) Whether or not you'd actually endanger anyone or get in trouble by ignoring that is a different question.

Putting something at the top of the drive seems a lot easier, and making that run a digital cable or wifi seems likely to be cheaper than trying to redirect the cell signal itself. Or, you could invest in a fire pit and an AC inverter and just watch the show from the drive and pretend you're camping.

You could also try cheap tricks to improve you cell reception in or near the house. One easy to try approach is to make a reflector by taking a big metal object, like a baking pan, (or, better yet, two of them taped together at a 90 degree angle), and placing the phone a few to a few 10s of cm in front of it while rotating and moving around and looking at the signal. I've used a big wok to do a similar thing a ham radio game called transmitter hunting with quite surprising success.
posted by eotvos at 10:20 AM on November 18, 2021 [5 favorites]

I'd be worried about the power consumption. Assuming that everything else worked, I doubt you'd have enough battery to support a less than 8oz hotspot continuously bridging wifi-to-cellular for three hours.

You're much better off connecting to a cellular router 100 yards down the drive. That distance is a little on the edge for ethernet, but with a PoE extender and a PoE enabled router, you should be good for both power and data. Just stick a normal hotspot on the house side of the wire after the PoE injector.
posted by RonButNotStupid at 10:27 AM on November 18, 2021

As fun as a balloon-assisted solution sounds, the most effective solution would probably be to run Cat5/6 cable up to the reception point and mount the signal receiver as high off the ground as you can (ideally in a tree or something, pointing towards the nearest signal if you can find it). Cat5/6 cable has a supposed max segment length of 100m/300~ft, but I've seen applications of 500-600ft that worked well enough. You should be able to buy that much cable for <$100 (unless the price has spiked recently).
posted by _DB_ at 10:27 AM on November 18, 2021 [1 favorite]

Response by poster: Sounds like running a cable up the hill or making a directional antenna is the way to go. This is disappointing from the standpoint of not getting to use a balloon, but much better in practical terms.

Thanks everybody!
posted by donpardo at 10:54 AM on November 18, 2021 [4 favorites]

Best answer: Yep, something like this where you can transmit power and data through 100 metres of ethernet cable should work pretty reliably compared to any other solution, but probably worth trying this with a full 100m of ethernet cable before you get out to the cottage.
posted by ambrosen at 11:13 AM on November 18, 2021

You might get away with it, but 100 yds (300ft/90m) of copper cabling will hit its design limit. A useful search term for the broader type of networking is "last mile".
posted by They sucked his brains out! at 11:51 AM on November 18, 2021

If you're exceeding that 100m limit on wired Ethernet by more than just a little (which most equipment is forgiving enough about), you can stick a PoE-powered network switch in the middle and have another 100m of distance available. There are also PoE extenders allowing another 100m, for example the Intellinet 560962, to feed a cellular modem still further up the drive. And in case the modem doesn't work with PoE there are separate splitters that offer 5V DC with a micro-USB or USB-C plug, or simply a barrel plug with 5V, 9V or 12V if that's what the modem needs.

Normally I would advise to use fiber over such distances outside, but a) you would still need to power the modem as well as the fiber converter at that end (though if only for a few hours you can get by with a big enough powerbank) and b) fiber likes being installed carefully and then left alone, where I take it from your description of the situation that you would set it up for the weekend, then take it down again (each weekend? couple of times per year? inbetween?).
posted by Stoneshop at 1:40 PM on November 18, 2021

It is certainly technically possible. The military has experimented with tethered balloons (technically "aerostats") for providing radio and WiFi-type coverage in valleys to pretty good effect. I think the usual way it works is with omnidirectional antennas on the aerostat, and then the ground stations use directional antennas and point it at the balloon if they are too far away from it to use normal omnidirectional antennas on the ground equipment. You could certainly do something like this by dangling a hotspot-enabled cellphone and then pointing a directional WiFi antenna at it from the ground/house. But the battery life may be a deal-breaker for something the length of an entire football game. I believe the military uses a ground tether that is both a physical cable and also provides power and data connections, so the aerostat itself doesn't have to carry a power supply as part of its payload. But sourcing something like that might be difficult, and the weight of a separate Cat5 and physical tether line might be heavier than just lofting an additional battery. You might need to experiment/play with it.

FWIW, although the "spec" maximum length of an Ethernet cable run is 100m, in practice you can often go further than this with high-quality cable. Particularly if you don't care about actual GigE speeds and are okay with 100Mb (which GigE will downgrade to automatically if needed). That should be totally sufficient for a wireless backhaul feed, since the bottleneck will almost undoubtedly be the cellular connection, not the 100Mb wire.

Anyway, if you want to do the balloon option, it sounds like a pretty neat project. There is a whole sub-hobby of Amateur Radio people who put various pieces of equipment up in balloons; you might want to do some searching around to see what people have already built or tried.
posted by Kadin2048 at 1:44 PM on November 18, 2021

Best answer: Pretty much however you do it, and assuming it works at all, the connection from the hotspot to the house is not going to be the bottleneck. So I would not spend a lot of time, effort or money on that. If you feel like running 100 yards of cable then go for it, and it should work as others have said. But if you can get power at both ends, the the simplest solution is probably point to point wifi bridging, which can get it done in 20 minutes for under $100.
posted by caek at 1:48 PM on November 18, 2021

Best answer: Why not use a slingshot to get a line up into a tree and haul the hotspot up? All it costs is rope and a slingshot, or a bow and arrow, or a throw bag, or a 2 liter bottle half filled with water…
posted by Geckwoistmeinauto at 10:42 AM on November 19, 2021