Heh. One of the escape sequences could be which language to use, so with the 16-bit scheme here, you could have 64K possible ones to choose from. Just have a 65,000 word table for each one.
You'd send out messages one language at a time. On Wednesday 25 August 2010 17:55:09 Graham Shirville wrote: > Hi Steve, > > I wonder how that would work with multiple languages:) > > 73 > > Graham G3VZV > ----- Original Message ----- > From: "STeve Andre'" <and...@msu.edu> > To: <amsat-bb@amsat.org> > Sent: Wednesday, August 25, 2010 10:24 PM > Subject: [amsat-bb] Re: New Satellite Downlink? > > > On Wednesday 25 August 2010 12:27:00 Robert Bruninga wrote: > >> Possible new AMSAT Application? > >> > >> We may have access to two old TRANSIT navigation satellites with > >> a 50 baud downlink at 149.985 (and 400 MHz). (presently coming > >> over in the mid afternoon). My problem is, coming up with any > >> meaningful application to use them for communications that would > >> capture the interest of students, hams or volunteers in support > >> of education, public service or emergency comms or just plain > >> fun... > >> > >> The downlink can be heard on an OMNI antenna (though I would > >> suggest a 3/4 wave (55") vertical) and could be decoded by a > >> simple software only application with a sound card. (someone has > >> to write it)... > >> > >> The total useful message capability is about 500 bytes > >> transmitted every 2 minutes (at 50 baud). The uplink is very > >> specialized and can ONLY BE DONE from one (or two) very special > >> commmand stations. These satellites of course were the original > >> Navy Navigation satellite system (also called OSCARS) and so the > >> message would be in-place of the normal navigation data. SO in > >> a sense, this is a downlink BROADCAST application. Since ham > >> radio is two way, I'm stumped for applications. > > > > Well, I'm not sure how many applications there are for this, but it > > could be fun to try some stuff. > > > > Way way back hundreds of years ago in the 70's I wrote some code > > to take English text and crunch it down and transmit it over a modem. > > > > I won't say the following is reasonable, but at 50 baud the little link > > needs all the help it can get. ;-) > > > > A lookup table can be made for about 65,000 of the most commonly > > used words plus various technical stuff. A message can then it > > converted into a series of 16-bit offsets into the table of words, > > taking 2 bytes (octets) per word. Printing out words takes the > > stream of data, does a lookup for each 16-bit quantity, prints > > that word plus a space, and goes on. > > > > A word like "communications" which is 14 bytes becomes two and > > is thus a win, but "a" "I" and the like is a loss. There could be an > > escape sequence to provide for the literal transmission of a word > > not in the 65,000 lookup table, and one could also be added for > > upper casing of the next word, etc. > > > > Doing this, you can transmit 250 words from the lookup table > > each minute, fairly faster than squirting out raw ASCII. > > > > Since you'd likely need a decoder no matter what the transmission > > is, the 65,000 word table is stored on the client side. Hilarity > > will probably ensue when someone doesn't update their table > > after a big change, and gets slightly demented messages till > > they update their code. > > > > Thinking about what to transmit... Possibly space weather > > transmissions? CMEs and such are something that has world > > wide impact. > > > > Well, that, or national lottery scores. > > > > > > -- > > STeve Andre' > > wb8wsf en82 > > Disease Control Warden > > Dept. of Political Science > > Michigan State University > > > > A day without Windows is like a day without a nuclear incident. > > _______________________________________________ > > Sent via amsat...@amsat.org. Opinions expressed are those of the author. > > Not an AMSAT-NA member? Join now to support the amateur satellite > > program! Subscription settings: > > http://amsat.org/mailman/listinfo/amsat-bb -- STeve Andre' Disease Control Warden Dept. of Political Science Michigan State University A day without Windows is like a day without a nuclear incident. _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
