As the US gets serious about opening up mobile broadband to its entire population, it is hunting for new spectrum options to support that. The UHF digital TV switchover spectrum sell-off brought in around $20bn, and one of the key uses of this 700MHz band will be to support long range radio signals to cover rural America more …
w.h.robinson icon required
So, with a Mifi device (recently on sale in UK) which joins 3g internet to a mini wifi access point, gaffa-taped to a hydrogen balloon (radio controlled versions available on firebox dot com), and maybe a tether to stop it getting lost and hey presto DIY Stratelite Broadband Combo... total cost about 180 quid.
No need for the ballon
If you only want to do one house then you just need some sort of pole on the roof to attach it to. All those redundant TV ariels should do,
would be nice, but...
8-12 hours? Maybe I'm wrong, but I'm guessing you need clear skies for a good launch (and/or a safe, predictable landing). I don't think it would be rare for large storm fronts (particularly hurricanes) to lead to interruptions of service... Satellite service may be crummy, but in my experience, at least it is reliable. Granted, storms can interrupt it as well, but if a launch window is interrupted, seems like it could effect your service even after the skies have cleared up?
Whatever happened to that company that wanted to put up smallish, geostationary blimps?
Sounds like ...
... reasonably doable, robust, laterally thought out solution to me.
I suppose the question is:
how will rural communities feel about having a balloon close by and how tempted will scallywags feel about taking a potshot at a comms balloon?
what happens to all the expended balloons? Do they parachute back to the ground with the comms unit, or are they cut free to litter the skies?
Overall, this doesn't sound very consistent and reliable. And it sounds like a whole lot of ongoing manual labor to launch and recover the units. Might be better to stick to the old 56k modems.
Sorry to spoil your McGuiver moments...
Re: would be nice, but...
These balloons go to slipstream altitude. Way above any storms, even the really nasty USA ones that actually pierce the tropospheric boundary.
RE: w.h.robinson icon required.
The balloon will be out of range before you can say uncle. Fitting a while base station, its relay electronics and the powerpack into something that a weather baloon can lift is not an easy task. On top of that, if you use 3G to connect to ground stations these will have to have their antennas changed. They presently do not point upwards. So there is no 3G coverage at 20km height.
"Space Data claimed it could save a new national wireless player $2bn, or construction of 8,500 new towers across the country,"
If you have the same amount of spectrum, then contention just got 8,500 times worse.
HSPA uses 5MHz per sector, or 15MHz per mast. To get near BB speed LTE needs to use 20MHz per sector, or 60MHz altogther.
Let's be generous and say the HAP has 400MHz. Covering the equivalent of 8,500 cells means 8,500 more people on average. Be generous and say the averaging is better on a big cell than loads of little ones, so call it 1000 times.
so per equivalent cell area we now have 400/1000 = 0.4MHz max. 24 times WORSE than 3G/HSPA and 96 worse than LTE.
Such a system is ONLY any use for a small number of emergency Workers, if accessing Internet as well as voice only about 1 simultaneous user per MHz of Spectrum.
In storm conditions it's useless. Storms has always been the problem for HAP. You need them at about 70,000ft even so.
100MHz bandwidth, so around 100 Mbit/s data rate (if satellite transponders are anything to go by). Over a 420 mile diameter circle (1500 sq miles). Any more than a few 1000 subscribers (1 per sq mile?) and you'd be better off with a dialup modem. Same problem that any aerial/satellite setup with a limited number of basestations will have.
Why not simply wireless meshed networks based on WLAN? That would probably be cheaper.
"how will rural communities feel about having a balloon close by and how tempted will scallywags feel about taking a potshot at a comms balloon?"
If it's at 60,000 feet you'll be doing well to see much more than a bright speck in the sky on a sunny day. As for taking potshots at it, your average bored redneck likely doesn't have access to the SAM launcher or interceptor aircraft he'd need to have a hope of hitting it, and will stick to shooting holes in road signs and random wildlife like they do already.
Sounds all well and good but...
US supplies of helium are dwindling... "The element that lifts things like balloons, spirits and voice ranges is being depleted so rapidly in the world's largest reserve, outside of Amarillo, Texas, that supplies are expected to be depleted there within the next eight years." That's somewhere around 2016. Once the supply is gone, it's gone forever... there's no easy or inexpensive way to create helium. There are other sources of helium in the US and Russia, but it's not being collected (it's a by-product of natural gas production) so who knows how much we'll have available in the coming decades... and as the supply gets smaller, the price is going to increase drastically.
I can't see hot air balloons being very viable... and I don't think people would be too keen on hydrogen filled balloons being used in their area... so it'll be interesting to see if this flies (pardon the pun.)
Air has a density of 1.2kg/cubic meter. Hydrogen is about 0.09, helium about 0.18. These are at sea level, 25celcius, and roughly remembered.
So according to Archimedes, a cubic meter- which is a lot bigger than the Firebox things- of helium has a "lift" of about 1kg and hydrogen about 1.1. The base stations are a few pounds (2.2lbs / kilo), presumably batteries add even more. So you're looking at several cubic meters of hydrogen or helium.
Then as you get higher the air thins out- increasing the pressure difference between outside and inside the balloon (necessitating slightly thicker walls) and decreasing lift. So that's even more cubic meters. Then you've got to compensate for the loss of battery efficiency in the colder air and the ice which may well form. And say you had a 5m diameter balloon that's almost 80 cubic meters of surface area on which ice can form and water can cling.
Plus it's got to hold up a load of tether (+ ice) or it'll either fly away or not get high enough to get good coverage. Tethers, though, are pretty dangerous if they're on or near a flight path. So you need an autonomous GPS-controlled thruster system + batteries or a huge overlap to make up for drifting stratellites.
Saying that, it could be done for a reasonable cost and would be really very useful for disaster recovery or providing point-to-point comms links where line-of-sight isn't an option. Just thinking- with a 125 mile range radius you could cover vast swarthes of the UK from outwith the range of Ofcom... pirate stratellite TV, anyone? With a hydrogen-leak-proof body, some thrusting/ sailboat-esque "tacking" mechanism and a few solar panels we could recapture the freeing subversiveness of pirate radio. But with pictures as well!
As Numbers Climb
It seems the FAA is going to have to step in if the numbers deployed get too high, when it gets to the point where hitting one with an airplane becomes better than needle-in-haystack odds. Granted the sky is a big place, the odds may never reach that someone out there will be worried about lawsuits if it ever were to happen.
Reusable kit in retrieval cost shock...
So, let us think a moment. The operator pays $100 to retrieve a unit worth $1,500, huh?
That unit is trackable, given the very nature of the task it performs: transmitting data.
it then gently parachutes back to earth in an area of the USA where the local population are almost universally equipped with (a) SUVs capable of going off road and (b) legally-held offensive weaponry.
Bloke in Space Data uniform turns up to collect kit. Finds heavily armed local in monster truck already holding said equipment in one hand and a heavy calibre machine gun in the other.
Price required to retrieve operator's $1,500 kit from SUV-man can now be confidently predicted to be somewhere north of $1,500, not $100.
Business plan kaputt.
Bandwidth MHz does not equal bit rate Mbps.
Digital transmissions don't send bits, they send symbols, where each symbol can code for more than one bit. The number of bits coded for depends on the coding scheme and coding scheme parameters. (Don't forget that baud rate actually means symbol rate, not bit rate).
E.g. as I write this, the 8 MHz wide multiplex at 641.833 MHz containing BBC channels for Cambs, has a payload data rate of 18.1 Mbps. That's after removing all of the overhead in the transmission and forward error correction schemes. ITV use a less robust transmission scheme so their mux at 665.833 MHz contains 24.1 Mbps of payload.
> Bandwidth MHz does not equal bit rate Mbps.
I know, but as a simple rule of thumb, for a signal that needs to be more robust than a digitized episode of Crossroads, it isn't too far out. Even at 2 or 3 Mbit/s per MHz, you're still not going to get adequate coverage of 1500miles² with 100MHz unless it's a very, very empty place...
I was curious more about getting the balloons up there in the first place, and how well they survive their return - not so much how they fare whilst they float about. Some storm systems can have large areas covered for hours; hurricanes ramp that up to days... It seems like you'd have to have significant overlap/redundancy to not be effected if your launch window is pushed back several hours. Also, for recovery, I'm guessing they would not want this parachuting down in severe weather either?
@Faster Better Greener
Never mind the SUVs and machine guns. That's irrelevant. If the Space Data guy finds himself being threatened with a machine gun, or even a broken bottle, he's just going to call the cops.
What is perhaps important is the law. If your equipment parachutes down onto my land, or if it lands in a public place and I get there first, are you entitled to insist on me giving it back to you? I don't know what the current law is, but I don't suppose it would be hard to modify the law so that Space Data can just call the cops when faced with an uncooperative local. To me it seems in no way unreasonable, nor unconstitutional, for the owner of the equipment to retain ownership in such cases.
"US supplies of helium are dwindling... "
So we'll switch to hydrogen. What could possibly go wrong?
@ Steve Coffman
Helium's not the only lifting gas. Some weather balloons use ammonia although it has a lower lift. And there's no reason why hydrogen couldn't be used in this case provided the operators only recruited non-smokers.
this is sooo balloon boy
something that turns out less awesome than originally hyped !
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