On Tuesday, February 08, 2011 David Barrett wrote: > How fast is it actually possible to go?
You can go as fast as you want - megabits, technically. But as you increase the modulation frequency (raise the baud rate), you increase the band width of the channel that you're using. This is shared media, remember. CB, for example, has 40 channels allocated to it, with freqs from 26.965 MHz (Channel 1) to 27.405 MHz (Cannel 40). These channels are typically separated by 10 kHz intervals (Channel 2 is 26.975 MHz, etc) with a few 20-KHz intervals thrown in just for fun. So as you raise the baud rate, your signal starts to take wider and wider channel band width, eventually getting into the next channel's frequency interval allocation. And since channel allocations were originally designed just wide enough to carry the low-quality voice - just as the phone network was - their digital carrying capacity is also close to what an old-school modem could do over the telephone network. I think you can actually go to 9600 baud with relative ease, but anything higher would be a challenge. Best wishes - S.Osokine. 8 Feb 2011. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Barrett Sent: Tuesday, February 08, 2011 8:43 AM To: [email protected] Subject: Re: [p2p-hackers] What we should build for the Egyptian (and other) protesters On 02/08/2011 08:03 AM, Eugen Leitl wrote: >> HF radio frequencies that enable reliable communication over long >> terrestrial distances don't have enough bandwidth to pass large amounts of >> data. 1200 baud is the maximum legal rate that Ham Radio operators can send >> using the 10 meter band, which ~28-30 MHz. ("CB" is ~26.xx-27.xx MHz). And >> the 10 meter band is not always reliable over long distances... Interesting: why is there a "maximum legal rate"? I assumed 1200 baud was just the fastest you could reliably get over such a low frequency connection. How fast is it actually possible to go? -david _______________________________________________ p2p-hackers mailing list [email protected] http://lists.zooko.com/mailman/listinfo/p2p-hackers Confidentiality notice: This message may contain confidential information. It is intended only for the person to whom it is addressed. If you are not that person, you should not use this message. We request that you notify us by replying to this message, and then delete all copies including any contained in your reply. Thank you. _______________________________________________ p2p-hackers mailing list [email protected] http://lists.zooko.com/mailman/listinfo/p2p-hackers
