Hi Joe Back home now and with Greg's help have built r6563 and forwarded it to Rex.
I see the facility to add noise to wave files recordings is no longer there. Is that correct? Charlie > Hi Rex, > > VK7MO wrote: >> I note that your conclusion that JT65c is no >> better than JT4 with spreading greater than 10 to 20 Hz is based on >> non-DS >> decoding. Based on my tests with r6536 I am inclined to agree that your >> conclusion also applies to DS decoding although I would like to do more >> testing when a build of r6559 is available. > > Good! -- additional tests are certainly desirable. > >> This conclusion does, however, seem to be contrary to the Text books >> that >> the use of higher Mary FSK should improve performance. > > No question: 64-ary FSK is a more efficient modulation than 2-ary or > 4-ary FSK. But it requires much more bandwidth. A JT65 submode with > information tone spacing comparable to JT4F would be something like > "JT65H", and would need ~20 kHz of bandwidth. > >> ... At present >> averaging is rarely useful on JT4f DS on WSJT-X as the limit is gaining >> sync >> - thus any improvement in gaining sync should be of significant benefit >> to >> JT4f averaging. >> >> So in summary I think the next move should be to do some wider tests to >> compare the sync performance of JT4f on WSJT10 and WSJT-X to see if >> there >> are options to optimise this mode before you spend time on JT65d. > > Agreed. I have not put recent effort into optimizing the JT4 decoder, > and you have already identified a weak spot to be worked on. > > Also keep in mind: As I argued many months ago, the best mode for > microwave EME may turn out to be a wide-spaced JT9 mode, say JT9G (111 > Hz tone spacing, 1 kHz total bandwidth) or JT9H (222 Hz, 2 kHz). These > submodes are already partially implemented in WSJT-X. Maybe it's time > to complete that effort. > > Also, Steve and I have been investigating ways to use one of the latest > hot things in communication theory -- Low Density Parity Check (LDPC) > codes -- for possible application in WSJT-X. So far we have been > thinking about a fast mode for meteor scatter, where we need a high rate > code, high symbol rate, and bandwidth-efficient modulation. > But we could also think about a code that would work well for EME. > > -- Joe, K1JT > > ------------------------------------------------------------------------------ > Transform Data into Opportunity. > Accelerate data analysis in your applications with > Intel Data Analytics Acceleration Library. > Click to learn more. > http://pubads.g.doubleclick.net/gampad/clk?id=278785471&iu=/4140 > _______________________________________________ > wsjt-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/wsjt-devel > ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785471&iu=/4140 _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
