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Email Over High-Frequency Radio in West Africa
Guillaume Filion writes "LinuxJournal has a fascinating article about Radio Email in West Africa over HF links. 'Deep inside the warm green interior of Guinea, centered in the frontal lobe of West Africa, field personnel in the widely scattered village-towns of Dabola, Kissidougou and Nzerekore now enjoy access to regular internet e-mail, directly from their desktops. Here we have bridged the digital divide, and there isn't a telephone line or satellite dish in sight.' Talk about Wireless Fidelity!"
The term 'baud' refers to 'lever transitions per second', not 'bits per second'. Baud and bps coincide at 2400bps and lower; however above 2400bps each baud carries more than one bit of data. Therefore, the term 'baud' becomes incorrect.
'bps' is faster to type anyhow.
But what do I know. I'm just looking for anonymous gay sex.
The last time I sailed across the ocean last July (in the Pacific Cup Race) we used an Iridium phone with the data option. We were able to send back a couple of digital pictures but the phone bill for the week was something like $200. Next time we'll save the pix till we hit land.
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"You are not remembered for doing what is expected of you." - Atul Chitnis
...now anyone in the world can dial in and see your messages.
i f
Seriously though, hams have been doing this kind of stuff for a while, on various bands. BBSes and email are commonly used (and tied together). There are TCP/IP networks (granted, most of them on bands like 2m which have higher throughput) with internet gateways. As a matter of fact, amateur radio operators have their own Class A (i belive it's 44.x.x.x)
PSK31 is used on the HF bands and gives you a real matrix feel. You can see the information coming down throughout the band, and click on the stream to see the text moving through it. Here's a screenshot: http://users.skynet.be/on1dht/media/rxpsk_scrn1.g
definitly cool stuff.
73, k6gnu
Volunteers in Technical Assistance (VITA) have been doing packet radio in the third world for years. Here is their page on communication technology.
The page also describes their LEO satellite system which is just now coming on line.
Pretty funny since there are gateways all over the net for this! You just have to be verfied by the operator of the gateway as a ham. Simple phone call, or e-mail would get initial verification. The next would be monitoring your use and making sure you don't use it for what it's not intended for (ie sending porn to other ham friends). This is the act of being a conrtol point operator. You are responsible for everything your station sends as the control point operator. When using a HT you are both the radio operator and control point operator, but sometimes you are not the one talking. Hence repeaters using volunteer control ops that listen to the local repeater via base station or handheld radio. There IS NO FCC Law or restrictiong regarding the use of packet radio except Part 97. Basically you can do whatever you want with it so long as you don't make money(have a pecuniary interest), and you don't send questionable content such as porn, music or other stuff otherwise against Part 97. Transfering MP3's over packet radio would be illegal as MP3 is music. Only way you could do that was if your the space shuttle (only exception to music in part 97 and this is because of the rebroadcasts of shuttle missions. Part 97 does not have the word internet in it and the word network only comes up once and that's in the line stating that a frequency band in the 220 MHz range is to be used for digital packet backbones. Other then that, this is NOT news. I transmitted a packet e-mail cross country before I ever sent a e-mail across country. HF so far has been limited to about 300 baud. I think the most you can do wirelessly using amateur radio is 14.4k(on 2m and maybe 440). The reason for this is because the faster you want to go, the wider your signal gets(hence the term bandwidth..). That's why there's a restriction for 300 baud on HF Frequencies. This may have changed as I don't really have all that much time to keep up on the digital modes. I don't think much has changed though with the excpetion of a couple guys were expermenting with using lasers for voice and possibly data (Would be THz range for RF I think).
Gorkman