Outernet helped me understand how expensive satellite data is

linagee · 2016-01-28T17:34:59.696Z

I’d like to use satellite data to send blockchain data. (Bitcoin, Ethereum, other blockchains.) At first I thought it might be possible to myself use a $50/mo satellite internet to accomplish this. But - if you were able to send your data up to satellite and have it repeated down (and somehow got off the shelf SDR understanding the data), it would only come back down to your spot beam. (Which means you’d only get ~100 miles of repeat since they keep them very small for a $50/mo satellite service.) It seems the $50/mo service I’m talking about is using Echostar 17 (HughesNet) and gives you 5GB of data per month. (plus off-peak data). So since its only 100 miles and you’d need more than 20 sites over the US to go to every spot beam, this seems like a really bad way to do it.

I’ve seen the number ~$1,000/mo thrown around previously, this would likely get you the ability to send data to a wider area. Multiple satellites for global coverage would be some multiple of this. (Quickly approaching over $10,000/mo+, way over anyone’s budget for mere hobbyist stuff unless you have very deep pockets.)

Outernet has taught me how expensive global broadcast of any data might be. 10MB/day suddenly seems like quite a deal. (But, that’s not big enough for any entire blockchain, probably big enough if you could subscribe to notifications and then just receive a few bytes when something hits your address. But I guess - this would then be similar to just having a satellite paging service.)

I’m also wondering about the Lantern. Can this device itself receive satellite communication, or does it need to be connected to a dish? (Because if no dish, how in the world can you get any signal indoors as their marketing photos show?)

branko · 2016-01-28T19:36:33.065Z

10MB/day is not the satellite beam. We can do around 1GB/day, iirc, over satellites.

EDIT: of course, that bandwidth is shared, so it won’t broadcast your blockchain at that rate.

barleyguy · 2016-01-28T21:27:35.768Z

If you want to send data to the entire footprint you don’t rent multiple spot beams, you rent full footprint bandwidth (called CONUS in the case of the US). A full transponder, which is roughly 40 Mbps, is about $1.5 Million a year. What generally happens is the owner of the satellite will rent out full transponders, and then a smaller company will rent out space by “kbps” increments.

10 MB a day is only 1.1 kbps, so it might be fairly reasonable for a monthly rental. The larger cost might be the uplink equipment.

(Actually, you CAN’T use multiple spot beams to send the same frequency to everyone in the footprint, because each of the spotbeams has a different set of frequencies. Probably not relevant, but there are more than 20 spot beams on a spot beam pattern. CONUS is 49 spot beams, based on the Lyngsat info for Echostar 10.)

EDIT: Also, if you want to know what it really costs to rent a small amount of bandwidth, you could just call Intelsat and ask them. I recommend them because they are probably the most open of the providers as far as dealing with individuals.

Syed · 2016-01-29T02:43:52.572Z

@linagee: On standard satellite internet plans, the spot beam is not the only limiting factor. The packets you receive are encrypted, so only your terminal can decrypt the message. I’m not aware of any current mulitcasting services available through satellite internet providers. They may exist, I’m just not aware.

What multicasting allows is for everyone to receive the same data. This is how Outernet works; everyone shares the same multicast client.

How large of a file is the blockchain? If it’s not too big, you can send it through Outernet now.

Lantern does not require a dish, as it is an L-band receiver with an integrated patch antenna. The antenna exists below the enclosure and is about 3-inches on each side (square). It is not able to receive satellite signals when indoors, but it can act as a wifi webserver inside.

I’ve always though that Bitcoin broadcasting would be a great use case for Outernet. Individual transactions can take place over WhatsApp or Twitter between buyer and seller and the transaction can then be sent added to the blockchain and broadcast over the air.

linagee · 2016-01-29T09:21:33.202Z

The Bitcoin blockchain is currently ~54GB. It grows about 2.1GB per month or 70MB per day. There is talk of increasing the block size which will make it grow perhaps 2x as fast. You kind of really don’t want to miss a block, so maybe re-transmitting a delayed stream would be necessary. If you mailed out the 54GB on some storage medium and had the retransmit time longer than your longest snail mail time, that maybe that would allow you access to all blocks in the chain. (All just theoretical.) Maybe you could transmit an outgoing Bitcoin transaction using SMS (or some long range radio), it would be just a few kilobytes. (source for blockchain size over time: Blockchain.com | Charts - Blockchain Size (MB))

With Ethereum, 71 days ago the blockchain was 3.0GB. Today, it is 7.8GB. That’s an average of 110MB per day.

Bitcoin is definitely the older more widely adopted cryptocurrency. Ethereum is the up and coming top altcoin that has an average of 17 second block times compared to Bitcoin’s 10 minute block times. (Some times much longer.)