> -----Ursprüngliche Nachricht----- > Von: digitalradio@yahoogroups.com > Gesendet: 13.01.07 02:36:52 > An: digitalradio@yahoogroups.com > Betreff: Re: [digitalradio] Re: Pactor versus Olivia
> > Rein, > > I am not clear on this. The B2F compression is used with Winlink 2000. I > am not sure what it really is other than a compression scheme to nearly > double plain text throughput and is some kind of adaptation to the > protocols that were adopted by FBB such as B1F. > > Shouldn't this work with even short data packets? It doesnŽt. You can try this yourself by zipping one line of `quick brown foxesŽ, and you will see the compression factor is nil. Then try to zip a 10k file full of Žquick brown foxesŽ, and see that it compresses to a factor of 1:50... > > If you were doing some keyboarding with an ARQ mode that was running at > 100 baud, like Pactor, (but could drop down according the conditions ... > unlike Pactor), and even if you used a cycle of 2 or 3 seconds > transmitting and .6 seconds open for ACK or NAK, wouldn't this still > work reasonably well with a throughput faster than most can keyboard? > And by using the B2F compression, and doubling the throughput, get > further enhancements? Pskmail gets good keyboarding results even when using PSK63 ARQ , which gives you PSK31 typing speed. Rein PA0R > > 73, > > Rick, KV9U > > > > Rein Couperus wrote: > > >>Unfortunately this won't work. BZ2 compression is based on 'redundancy' in > >>a message. There is hardly any redundancy in short messages as used in > >>k-to-k. > >> > >>The only way you can do that is by using context-based compression, like > >>the 'context based huffman' compression in pskmail, which reaches > >>compression factors of 1 ... 50 : 1. > >> > >>Rein PA0R > >> > >>(by the way, it is open source). > >> > >> > >> > Rick, KV9U had previously said: > > By the way, I have often wondered why the B2F binary compression system > used with the Winlink 2000 system has never been used for nearly a 2:1 > compression for improved throughput. This could be applied to any > system, including keyboarding. > > 73, > > Rick, KV9U > > > > > Announce your digital presence via our DX Cluster > telnet://cluster.dynalias.org > > Our other groups: > > http://groups.yahoo.com/group/dxlist/ > http://groups.yahoo.com/group/themixwgroup > http://groups.yahoo.com/group/contesting > http://groups.yahoo.com/group/wnyar > http://groups.yahoo.com/group/Omnibus97 > > > Yahoo! Groups Links > > > > -- http://pa0r.blogspirit.com Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
