Topic: Broadcasting the Blockchain - page 3. (Read 10493 times)

After checking my own shortwave receiver, which I believe to be fairly representative of the kinds of reciever available most of the world around, is tunable between 19,990 and 30,000 khz using it's third (final) SW band setting.  This encompasses the international shortwave bands of 15 meters (18,900–19,020 kHz) 13 meters (21,450–21,850 kHz) and 11 meters (25,600–26,100 kHz).  All three of these bands are pretty much useless for international broadcasters because it's rare for the critical frequency to spike that high, at least not reliablely enough for a broadcaster to use.  For this reason, 11 meters is a common citizen's band in many countries and 13 meters is a regional AM band in Pacific Asia.  Wikipedia says that 15 meters is rarely utilized, and may be reallocated to DRM broadcasters in the future.

Perfect.

What needs to be done is that someone in a country that is signatory to the communications treaties needs to get a broadcasting license from their country to broadcast in the 15 meter band.  The United States is notoriously unlikely to approve such a broadcasting license, so it'd be better for someone in another country to attempt it.  I might still attempt it, but I'm not going to pursue it if it requires a $10K broadcasting fee, obviously.  The sats would still have to be aware of all licensed broadcasters in this band, and avoid them whenever possible.  I'm pretty sure that this is also a ham band, but not one that I've ever known any hams to use, as local hams use 2 meters and 70 cm while distance hams use 20, 40 and 80 meters.

A modified AM shortwave receiver could simply involve an audio output jack wired to the audio input jack of a computer sound card, with an accompaning app that can fit on a small usb drive and instructions for locating the right frequency and capturing the data stream.

Unfortunately, I can see some very real technical and legal issues with trying to do this as described.

First off, Wifi is possible in only two bands.  Since the higher N band is very new, and many smartphones still don't support it, I'm going to assume that the older B,G band is what they plan to use.  But there was a technical reason that this band was chosen at the time of development; namely that the B,G band was license free worldwide.  But why was that, since such license free technologies didn't really exist before Wifi itself?  Because the B,G band is the resonate frequency of hydrogen.  Thus, energy transmitted in this band is heavily attenuated by any water or hydrocarbons found in it's path, and was considered useless for distance communications.  This is still true, and has much to do with why Wifi is so poor at clear range.  It's also why this band is shared by every retail microwave that I know of, since food is pretty much all hydrocarbons and water.  While there wouldn't likely be much risk of hydrocarbons in the line of sight from low earth orbit, there would be much water.  On average, the Earth's atmosphere has enough water from space to sea level to equate to a 32 foot deep dive under the ocean's surface.  The amount of power that would be required to push through this and be receivable by common wifi hardware on the Earth's surface would be rediculous.

Second, there are also sound techincal reasons as to why wifi multicasting is not commonly used.  Mostly because wifi is a time-sharing technology that (generally) permits more than one unrelated connection to coexist on the same channel.  This is permitted because normal mode wifi requires that the hotspot 'listen' to it's own channel several times per second for other broadcasters trying to share the channel space.  This doesn't always work well, but it does work more often than most people realize.  However, a hotspot in space couldn't coordinate timesharing of all the hotspots in it's radio shadow even if it were possible for it to hear them.  In this case, the sat based signal would effectively 'jam' the chosen channel across the whole of it's radio shadow, and also be a violation of international communications treaties as a result.

Third, the licesne free broadcasting nature of the B,G band is limited to 'terrestrial' transmitters, and therefore doesn't apply to satillites at all.  A new treaty would be required to even permit such a license, since every country has max transmitter powers in the B,G band that would be WAY below what a sat would require.

While using the new N band would reduce the power requirements considerablely, the other two issues would still apply.  Perhaps a lower frequency license free band would work with modified FM band recievers, but I can't see a way around the international communications treaties regarding this.  Perhaps a broadcast stream that can switch around frequencies in the higher frequency shortwave bands would work, but the sat would have to be able to respond to the reflectivity of the ionosphere and changes in the critical frequency.  Most Shortwave broadcasters have to stay below the critical frequency so that their Earth bound transmitters can reflect their signal off of the F layer of the ionosphere, but what about a broadcaster in teh shortwave bands that deliberately stays above the critical frequency so that his signal is not reflected back into space?  Regardless, the data throughput woudl be low due to a narrow usable bandwidth and a particularly 'noisey' radio environment in those bands.

The project looks great...


Let's see how it will turn out

Looks like someone is going to attempt this:

https://www.outernet.is/

For practical purposes an offline client such as Armory or an online wallet like (pick your favorite) will work fine over any phone line.

On the other hand I'd still like to see this happen just because it's cool. 

It now only costs 1,000,000 BTC!

I like this idea! A BitStar satellite.

Sure it is.  The idea isn't particularly useful if mining, because mining requires as little a delay as possible.  Regular clients, however, can tolerate transmission delays just fine.  It's useful for getting the blockchain to parts of the world that Internet access is sparse or prohibitively expensive.

Interesting.  I like your idea about a channel on digital satellite radio.  I wonder if those $11 SDR receivers would be capable of decoding this.


Part of my original thought was that there are places where electricity is basically free at least part of the time.  But you're right, the idea isn't very useful if not mining.

https://bitcointalksearch.org/topic/datacasting-the-blockchain-2039

Do people really have mining gear and reliable electricity in places that this would help? And won't a phone call when they need to check on or make a payment be all they need if not mining?

Good point. There are already amateur radio satellites in the orbit.  If they ever start broadcasting blockchain, I suggest we rename the network: Orbitcoin.

The Bitcoin blockchain can be kept up-to-date with less than a 2400 baud connection.  This is within the limits of amateur packet radio technology.  Using standard HAM radio transmitters and cheap SDR receivers, this can enable an unlimited number of clients to perform transaction verification and mining, possibly in remote locations, without requiring a dedicated internet connection.  A separate uplink, such as a phone line or perhaps two-way pager, can be used intermittently to initiate transactions or to transmit mined blocks.

What do you think?  Could this concept be economical in developing countries, or in areas with high internet costs?  Could it perhaps one day enable miners to reclaim stranded renewable energy during periods of overproduction?  Could it even justify dedicated satellite or unmanned aerial transmitters?  Or is this concept simply wildly-unrealistic, pie-in-the-sky speculation?