Right, ypu need the size, not just the fact that it is the mode. However, if you just use the MFSK code and then send the size info in MFSK, it would be 100% compatible with existing implementations. So, it is mostly a UI thing, allowing people in Olivia or some other mode of about the same bandwidth to initiate an MFSK picture transmission without the cognitive overhead of switching to MFSK. PSK users probably wouldn't want to do this unless there is enough clear bandwidth available.
73, Leigh/WA5ZNU On Mon, 21 Jan 2008 10:54 am, Patrick Lindecker wrote: > Hello Leigh, > >> RSID is now available in open source C++ pocketdigi so I suspect it >> will > > RSID define modes and has a limited number of combinations available. > Here you would need perhaps 24 bits to define all the information > needed. So a more classical (hard decision instead of soft decision) > and a bigger RS coding would be necessary, which is not a big problem > but days are too short... > > 73 > > Patrick > >> ----- Original Message ----- >> >> From: Leigh L Klotz, Jr. >> >> To: digitalradio@yahoogroups.com >> >> Sent: Monday, January 21, 2008 5:49 AM >> >> Subject: Re: [digitalradio] Re: Redefining SSTV operations >> >> Patrick, >> >> The advantage of the MFSK analog picture mode is that it is already >> widely implemented, and almost all implementors of MFSK have it. Your >> RSID is now available in open source C++ pocketdigi so I suspect it >> will >> be incorporated into more programs as well. Put the two together and >> the mode will be widely available fairly soon. >> 73, >> Leigh/WA5ZNU >> On Sun, 20 Jan 2008 3:14 pm, Patrick Lindecker wrote: >>> Sholto, >>> >>>> Patrick, I just assumed that a digital SSTV mode in 500Hz that could >>>> send a >>> >>>> decent size picture in a reasonable amount of time was impossible. >>> >>> With a standard modulation and a standard compression scheme you are >>> perfectly right, but, perhaps, with some modulation as the one used by >>> Cesco for FDMDV and a very powerful compression scheme, it's perhaps >>> possible. A big challenge in all cases. >>> >>>> Then error correction could also be applied... >>> >>> Yes, it would be ideal. >>> >>> 73 >>> >>> Patrick >>> >>>> ----- Original Message ----- >>>> >>>> From: Sholto Fisher >>>> >>>> To: digitalradio@yahoogroups.com >>>> >>>> Sent: Sunday, January 20, 2008 11:56 PM >>>> >>>> Subject: Re: [digitalradio] Re: Redefining SSTV operations >>>> >>>> Patrick, I just assumed that a digital SSTV mode in 500Hz that could >>>> send a >>>> decent size picture in a reasonable amount of time was impossible. >>>> Certainly >>>> if it is possible then it would make more sense to look at that >>>> approach. >>>> Then error correction could also be applied... >>>> >>>> 73, Sholto KE7HPV. >>>> >>>> ----- Original Message ----- >>>> From: "Patrick Lindecker" <[EMAIL PROTECTED]> >>>> To: <digitalradio@yahoogroups.com> >>>> Sent: Sunday, January 20, 2008 2:50 PM >>>> Subject: Re: [digitalradio] Re: Redefining SSTV operations >>>> >>>> Hello Sholto, >>>> >>>> MFSK SSTV is an analogical SSTV mode with the originality that it is a >>>> narrow band SSTV mode (the same as MFSK) and the format of the picture >>>> is >>>> free (small or big as you want). >>>> >>>> It would be possible to put some RS prefix (with more bits available >>>> than >>>> for RS ID) to define the center frequency, format and color. But I'm >>>> not >>>> sure that the gain would be important as this type of SSTV is an "old" >>>> technology. Better would be a Digital SSTV within 500 Hz and as >>>> fast as >>>> standard SSTV. >>>> >>>> 73 >>>> Patrick >>> >>> > >
