-I have had the same experience as Rick, some helpful hams but some grumpy hams on the usual SSTV frequencies. Also, too much talking. Like, one picture sent and 5 minutes of chit-cat. Like some of the less-used digital modes, SSTV is only used by a small amount of hams, and you tend to run in to the same few hams over and over again.
With the experiments here in the past week, we can redefine the basic guide to SSTV. In fact, I am not sure term SLOW-SCAN fully applies any more. Here is a quick view : Wide Analogue SSTV: Exceeds 500 Hz wide and thus in th USA requires the frequency used to be within the portions of the bands defined for "image". Most popular frequency is 14230. Used to exchange pictures , operator use voice SSB on same frequency to discuss pictures and the mode in general . MMSTV and Multipsk are popular software for these modes. DM780 has a pending beta that also supports these modes. Narow Analogue SSTV. Using SSTV modes that are less than 500 Hz appears to allow USA operators to utilize the the same portion of the bands assigned to other digital mdoes like PS31 or RTTY. The picture sent is viewed as "data". Modes such as MP73-N (found in MMSTV) are used with text overlays for signal reports, etc. SSB voice transmissions are not used between tranfers. Most used frequencies seem to be 10132 and 7077.Not sure about other countries. MFSK16 with pictures. Multipsk and Mixw allow for a digital QSO with MFSK16 and switch to a narrow mode picture transfer method when the users decide. Pictures are small. Use the same frequencies that you normally use MFSK16. Try 14077, 7035, 7077. Digital SSTV: Easypal, Hampal and other digital SSTV applications transfer pictures digitally rather than analogue. The received picture quality is a good as the original picture . These applications use a method that has some error detection. The sofware detects "segments" of a picture that are not received fully, at the end of the transfer the receiving station sends a "BSR" (Bad Signal Report) alerting the originating station as to which segments were not correctly received. The originating station then sends a "fix", sending just the segments the other station needed. This software can also be used for general file transfers. There is quite a bit of activity, look first for signals on 14233. RSFM: I have included this software in the discussion of SSTV because, like digital SSTV, it is more of a file transfer program. You send your pictures as a file and , if received, the picture is as good as the original. It works under the standard MIL-STD-188- 110A . The file transfers utilize a rather broad bandwidth and also use a automatic error correcting method. In the USA there are limits on how/where the software can be used in the amateur bands, but there is much activity with this modee in Europe, Canada, and Australia. Others: WinDRM and DigiTRX also allow file transfers similar to Easypal, thus pictures can also be sent. With WinDRM you can also talk via digital voice. Andy K3UK -- In digitalradio@yahoogroups.com, Rick <[EMAIL PROTECTED]> wrote: > > Hi Bob, > > The digital modes are not often mixed with analog and since the analog > were there first, they tend to use the lower frequency, particularly on > 20 meters. > > Since you are quite close to me, you may find that best signals on 40 > meters as a good choice. The most active operator is Dave Jones, KB4YZ, > located in Indiana. > > Most of operation on 40 meters is digital SSTV but some hams may still > be operating analog on 20 or other frequencies. There may be > Yahoogroups, but one thing about SSTV is that all the coordination is > done with voice and that probably means SSB voice most of the time, so > you can ask questions. Dave is very helpful and pleasant although I have > found some of the older hams to be a bit unpleasant with newcomers who > ask questions. > > The most popular software at the moment seems to be EasyPal and seems to > have eclipsed WinDRM for digital SSTV. > > I recommend Dave's site for SSTV information: > > http://www.kiva.net/~djones/ > > Scroll down to the EasyPal (New Version) section for information and > downloads. > > 73, > > Rick, KV9U > > > > > Bob Christenson wrote: > > Hi guys, I'm looking into SSTV. I see that popular frequencies to > > operate it are 7171, 7173, 14230 and 14233. Are these pictures sent > > using an analog or digital method? What popular software is being > > used? Is there another Yahoo group for this? Thanks for the help. Bob > > C (WU9Q) > > > > >
