Re: [digitalradio] Re: Pactor versus Olivia
-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/
Re: [digitalradio] Re: Pactor versus Olivia
Lossless compression does not work if there is no redundancy. The Quick Brown Fox has one of each symbol on the alphabet. Jose, CO2JA Rein Couperus wrote: -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 * 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/
Re: [digitalradio] Re: Pactor versus Olivia
Rick, This is certainly lost on the Pactor III group. 73, Mark N5RFX having many small bandwidth users means more throughput for more users than one large bandwidth user at a time.
Re: [digitalradio] Re: Pactor versus Olivia
I am afraid it is as Rein says. FBB, which uses B1F compression (hope I remember right) does not compress the sysop keyboard, but just the BBS traffic. JNOS has a compressed ttylink mode that uses LZW and has never worked for me (compile errors), but which might provide an edge. PTC-II boxes can do Huffman and some other sort of limited compression on the fly, but only has english and german Huffman tables. It is NOT used on BBS FWD. 73 de Jose, CO2JA KV9U wrote: 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? 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? 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 * 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/
Re: [digitalradio] Re: Pactor versus Olivia
Not bad...but quite a few DXpeditions and less luck people cannot rely on full time Internet. This is ham radio... Jose CO2JA Dave Bernstein wrote: Why stop there, Leigh? With the use of QRZ.com and weather.com to independently determine name, QTH, and weather conditions, you could encode many QSOs into a pair of callsigns plus one byte. 73, Dave, AA6YQ
Re: [digitalradio] Re: Pactor versus Olivia
Leigh L. Klotz, Jr. wrote: But why stop there, as you say? I'm reasonably sure someone's already done this (from the scores I see in the contest logs) but it should be possible to totally automate the RTTY contests. With wide-band SDR receivers (and transmitters for that matter) it ought to be possible to work the whole contest automatically. This same concept could easily be extended to macro-based ragchewing popular on PSK, with the digimode programs automatically doing search-and-pounce, macro exchange, and LoTW or eQSL QSLing.The mind boggles! Don't stop there, either! This can be done for nearly ALL Qso's, not just contests. - Scan for unworked stations - Call one when you find one - Search the FCC database or QRZ for name and QTH - Search weather.com for the weather - Search the archive of all the monitored QSO's your computer has ever seen to get information on rig, medical history, family, work, etc. - Search google for off-the-air postings to complete the personality profile - Enter all the data into an AI program on your computer - Have a qso with the clone in your AI program - disconnect. Two-second qso's with rare DX stations could be a thing of the past; a rare DX station could have hundreds of simultaneous QSO's just by allowing multiple connections. Note: QSO's in excess of 30 minutes could qualify you for a synthetic rag chewing certificate. - ps
Re: [digitalradio] Re: Pactor versus Olivia
The Winlink 2000 promoter brings up B2F from time to time with the claim that this is what makes their system have the extra efficiency. But apparently this is a bit overstated. Is it possible to use more compression in the current keyboard modes or is Varicode about as good as can be expected? Varicode doesn't come close to a 2:1 compression, does it? Modes such as Pactor use many different enhancements so that when you put it all together, you have a superior mode. The one area that Pactor may fall down is that the baud rate is too high for some conditions and at those times other modes might work better that have slower baud rates and a similar modulation scheme. However, I still can not understand why Pactor modes work as fast as they do compared with non-ARQ sound card modes. Ignoring the issue of errors, one would think that a non ARQ mode would always run faster than an ARQ mode. Since any modulation scheme you can do in a discrete box should be able to be done with computer DSP/soundcards why is there such a discrepancy? 73, Rick, KV9U Jose A. Amador wrote: I am afraid it is as Rein says. FBB, which uses B1F compression (hope I remember right) does not compress the sysop keyboard, but just the BBS traffic. JNOS has a compressed ttylink mode that uses LZW and has never worked for me (compile errors), but which might provide an edge. PTC-II boxes can do Huffman and some other sort of limited compression on the fly, but only has english and german Huffman tables. It is NOT used on BBS FWD. 73 de Jose, CO2JA KV9U wrote: 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? 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? 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). R 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/
Re: [digitalradio] Re: Pactor versus Olivia
If it is the same protocol as B1F, was the reason for developing it, that the B1F did not have the needed exchange to work with Winlink 2000? So it is basically an extended version to do more things that they need to have it do? I don't think that I am fully understanding what your code is being written for? Are you writing what would be considered an open source version of B2F so that it could be used across all platforms to access the Winlink 2000 system through the internet? Is there any way to improve interoperability between say, a PSKmail system and Winlink 2000 system? On a separate note, how feasible is it to incorporate L-Z/Huffman combined compression in any data mode, including keyboard mode? 73, Rick, KV9U N2QZ wrote: B2F compression is a misnomer. B2F is the message structure and message exchange proposal protocol used for email messages in Winlink 2000. The WL2K messages are compressed, but they use *exactly* the same Lempel-Ziv Huffman compression as the F6FBB B1F protocol. What differs from F6FBB is the FC message proposal, and the email format messages exchanged. http://www.winlink.org/B2F.htm Working source code is available. It doesn't talk to any TNCs yet, but all the B2F stuff has been working for some time. It can exchange messages with the WL2K servers over the Internet using a telnet connection. By the way, if anyone wants to help work on this project, let me know. My available free time to work on this is becoming increasingly negative. http://sourceforge.net/projects/paclink-unix 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/
Re: [digitalradio] Re: Pactor versus Olivia
There is already a degree of Huffman-type compression in PSK31 via the Varicode, where the number of bits per symbol depends on symbol frequency. Compression that depends on the text that went before it could be more efficient, but would lead to total loss of the following text in the ecent of an uncorrected error. In order to prevent that loss, you have to be able to resync quickly to recover from errors. PSK31 does this with the character stop bits, limiting the damage to one letter. (I.e., the block size is 1 char.) Allowing references further would need to be combined with at least a block mechanism, so that the RX side would know to restart. For example CCIT G3 Fax uses run-length coding within a lone, limiting damage to an area of a line, G4 fax, designed for ISDN which was expectted to be less noisy, uses a back-reference that can refer to repeating regions within a group of 4 lines, limiting the damage to 4 lines. (Also the greater compression allows the use of higher resolution images, making the lines smaller too.) It isn't immediately clear how to apply this slight increase in block size to PSK, since I don't see any easy boundaries other than characters. ECC of some sort on the blocks would make the compression more useful, so you wouldn't lose a whole block. An ACK/NACK mechanism (ARQ) could help make use of the ECC info, and since you could depend on the receipt of previous blocks you could count on references between them. So, it is a slippery slope away from keyboarding. Leigh/WA5ZNU On Sat, 13 Jan 2007 7:11 am, KV9U wrote: On a separate note, how feasible is it to incorporate L-Z/Huffman combined compression in any data mode, including keyboard mode?
Re: [digitalradio] Re: Pactor versus Olivia
KV9U wrote: If it is the same protocol as B1F, was the reason for developing it, that the B1F did not have the needed exchange to work with Winlink 2000? I'm not really sure what that means, and I'm pretty sure I didn't say B2F is the same protocol as B1F. Only the compression is the same. So it is basically an extended version to do more things that they need to have it do? It's just the internal format for handling email messages on the Winlink 2000 system, and the protocols for the systems handling the emails to negotiate the transfer. I don't think that I am fully understanding what your code is being written for? Are you writing what would be considered an open source version of B2F so that it could be used across all platforms to access the Winlink 2000 system through the internet? What would be considered? It *is* an open source cross-platform Winlink 2000 client, released under the GNU General Public License (GPL). Why not have a look for yourself? Through the internet? No, that's just the first step to having a working client; eventually it will work over the radio. In fact it has been on the air a few times, but not really in a fully functional way. The code in the sourceforge repository has a very brainless TNC driver, which needs to be rewritten from scratch to use WA8DED hostmode and/or KISS. In fact, if there are any TNCs out there that are binary transparent in command mode, the existing driver could probably be used on the air today. My SCS PCT-IIpro is not, and the documentation I have suggests that hostmode is the way to get binary transparency. When will it be fully functional? When I get around to it, or when someone else pitches in some help, which was my primary motivation for making it open source. Is there any way to improve interoperability between say, a PSKmail system and Winlink 2000 system? I don't really know much about PSKmail. It sounds like an interesting system, but I've never looked at it beyond a cursory glance. One of these years I'll find the time, I'm sure. But one of my motivations for releasing my code as open source was to promote interoperability with WL2K. It would be great if someone used my work to figure out how to add WL2K compatibility to a system like JNOS2. Since JNOS2 can already talk to several TNCs, and my code can talk to the WL2K servers, the marriage of the two would be a very good thing. On a separate note, how feasible is it to incorporate L-Z/Huffman combined compression in any data mode, including keyboard mode? It isn't very well suited to compression of single characters or tiny sequences of characters. To get good compression ratios, it needs to have a substantial stream of characters to work with. Otherwise the overhead for the compressed stream will be greater than the compression savings. For example, if I put my callsign (followed by a linefeed) in a file and compress it, the original file is 5 bytes and the compressed file is 12 bytes. But when I put my callsign in a file 100 times, the compression savings is significant, with the 500 byte file shrinking to 30 bytes: Script started on Sat Jan 13 17:17:03 2007 [501]~/sourceforge.net/work/paclink-unix $ echo n2qz text.txt [502]~/sourceforge.net/work/paclink-unix $ ./lzhuf_1 e1 test.txt test.txt.lzh 5 In : 5 bytes Out: 6 bytes Out/In: 1.200 CRC: 3a10 [503]~/sourceforge.net/work/paclink-unix $ wc -c test.txt* 5 test.txt 12 test.txt.lzh 17 total [504]~/sourceforge.net/work/paclink-unix $ yes n2qz | head -100 test.txt [505]~/sourceforge.net/work/paclink-unix $ ./lzhuf_1 e1 test.txt test.txt.lzh 61 In : 500 bytes Out: 24 bytes Out/In: 0.048 CRC: fdce [506]~/sourceforge.net/work/paclink-unix $ wc -c test.txt* 500 test.txt 30 test.txt.lzh 530 total [507]~/sourceforge.net/work/paclink-unix $ exit Script done on Sat Jan 13 17:18:28 2007 -- 73 de Nick N2QZ Section Traffic Manager, Eastern New York Section Net Manager, NYS/E FISTS #11469 SKCC #1027 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/
RE: [digitalradio] Re: Pactor versus Olivia
MT63 2.2 KHz/20/ch/sec = 110 KHz-sec Should be MT63 2.2 KHz/20/ch/sec = 110 Hz-sec 2200/20 = 110 Isn't it more meaningful to say that for each 110 Hz of bandwidth, you get one character? But since MT63 uses interleaving to obtain error free copy and not ARQ, you might better realize that MT63 uses 2200 Hz for 80 characters or 27.5 Hz to get one character. To obtain a better BER you have two choices...more FEC or more ARQ (tries) or a combination of either. As someone said, comparing ARQ modes with FEC modes is comparing apples and oranges. Only if you use both ARQ and FEC can you make a valid comparison. Walt/K5YFW -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of KV9U Sent: Thursday, January 11, 2007 5:31 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Pactor versus Olivia I have seen the claim for a good operator able to copy down to about -15 db S/N for CW operation. Some of the digital soundcard modes are supposed to be able to still have throughput down around -15 depending upon other factors such as doppler, ISI, etc. Using Multipsk, and I don't know how accurate this is, I can at least copy down to at least -10 with CW according to the readout display on S/N ratio, but even though I am over 60, my hearing is still quite good. I would not be willing to make too close a comparison between an ARQ and non-ARQ mode, but the footprint numbers were posited by Rick, KN6KB in his RFfootprints Powerpoint presentation. In comparing different modes, he claims that P3 is the superior mode, even to RDFT which he used to develop the SCAMP mode. He uses a spacing of 200 Hz between signals and that may or may not be entirely fair since the really narrow modes can work a lot closer than that from my experience. He comes up with a calculation of KHz-seconds by dividing the bandwidth by the characters per second, thus: MT63 2.2 KHz/20/ch/sec = 110 KHz-sec PSK31 .25 KHz/4 ch/sec = 62 HF Packet 1.7 KHz/37 ch/sec = 46 Pactor1 .55 KHz/20ch/sec = 28 RDFT2.2 KHz/97 ch/sec = 23 Pactor 2 .7 KHz/50/ch/sec = 14 Pactor 3 2.4KHz/225 ch/sec = 10 Of course this assumes everything is flowing perfectly and under most conditions some of the modes will seriously degrade, particularly HF Packet. MT-63 and PSK31 would stay at the same rate until they fail to get through. At that point, the Pactor modes would have slowed down to a fraction of their high speed and their numbers would not look as good. Perhaps they would move into the 30 to 60 range? At only 5 cps for a wide mode like P3 (but narrower at the slower speed levels at maybe 2000 Hz including a guard band), that would be 2000/5 = 400 KHz-sec and be extremely poor. Even at 20 cps, P3 would not have a favorable footprint anymore. 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 DuBose Walt Civ AETC CONS/LGCA wrote: Well I can't hear a CW signal at a -5 dB SNR. Can you? But I don't think minus teens...but that is what some of the newer PSK modes claim. The only thing that will really kill or stop Pactor is excessive amounts of doppler or until the detector can no longer decode the signal. You are actually making a case for RF footprinting. You want to see what the throughput is for bandwidth unit. We could measure it in Hz or KHz. 20 cps at 1 KHz is .04 cps/Hz (MT63-1K RAW). 5 cps at 100 Hz is also 4.5 cps is .05625 cps/Hz (PSK31). But when decoded, MT63 is almost 100% error free and PSK31 can have up to 10% errors. So it not all just about throughput, its about the overall robustness of the mode to include your requirement for how much error free copy you want. You are going to get many few errors with Pactor III than PSK31. If you used ARQ and something else to to the the BER of PACTOR III, you might find that the throughput was less than 5 cps. Walt/K5YFW 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
RE: [digitalradio] Re: Pactor versus Olivia
-Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 17:09:44 An: digitalradio@yahoogroups.com Betreff: RE: [digitalradio] Re: Pactor versus Olivia 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 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). -- 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/
Re: [digitalradio] Re: Pactor versus Olivia
Here's a modest proposal: compress most of the QSO the way the moonbounce modes do, by knowing what is expected at that point and expressing it in a few bits. For PSK, we could just standardize on macro names for a few things and the two modems can negotiate about whether to expand them on TX or RX. Instead of sending Your RST is 599 when the macro is RST the TX could just send ^RST and the RX modem can expand this into Your RST is 599. And if you send ^STATION ^BRAG the RX program can just print OM sent you a big list of his computer equipment. This might also eliminate a lot of the uppercase text as well... Leigh/WA5ZNU On Fri, 12 Jan 2007 1:02 pm, Rein Couperus wrote: -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 17:09:44 An: digitalradio@yahoogroups.com Betreff: RE: [digitalradio] Re: Pactor versus Olivia 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 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). -- 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 http://docs.yahoo.com/info/terms/
Re: [digitalradio] Re: Pactor versus Olivia
-Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 22:24:49 An: digitalradio@yahoogroups.com Betreff: Re: [digitalradio] Re: Pactor versus Olivia Here's a modest proposal: compress most of the QSO the way the moonbounce modes do, by knowing what is expected at that point and expressing it in a few bits. For PSK, we could just standardize on macro names for a few things and the two modems can negotiate about whether to expand them on TX or RX. Instead of sending Your RST is 599 when the macro is RST the TX could just send ^RST and the RX modem can expand this into Your RST is 599. And if you send ^STATION ^BRAG the RX program can just print OM sent you a big list of his computer equipment. This might also eliminate a lot of the uppercase text as well... For a standard PSK31 qso you could actually reduce this to 1 byte per concept. (^STATION ^BRAG) could easily be coded as '!'' For pskmail, which does not know what it will get an international word table of some 18000 words codes words into 1 (most used) or 2 bytes. Supercalifragilisticexpialidocious = 'xP'. Rein Leigh/WA5ZNU On Fri, 12 Jan 2007 1:02 pm, Rein Couperus wrote: -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 17:09:44 An: digitalradio@yahoogroups.com Betreff: RE: [digitalradio] Re: Pactor versus Olivia 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 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). -- 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 http://docs.yahoo.com/info/terms/ 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/
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? 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? 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 * 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/
Re: [digitalradio] Re: Pactor versus Olivia
KV9U wrote: 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. B2F compression is a misnomer. B2F is the message structure and message exchange proposal protocol used for email messages in Winlink 2000. The WL2K messages are compressed, but they use *exactly* the same Lempel-Ziv Huffman compression as the F6FBB B1F protocol. What differs from F6FBB is the FC message proposal, and the email format messages exchanged. http://www.winlink.org/B2F.htm Working source code is available. It doesn't talk to any TNCs yet, but all the B2F stuff has been working for some time. It can exchange messages with the WL2K servers over the Internet using a telnet connection. By the way, if anyone wants to help work on this project, let me know. My available free time to work on this is becoming increasingly negative. http://sourceforge.net/projects/paclink-unix -- 73 de Nick N2QZ Section Traffic Manager, Eastern New York Section Net Manager, NYS/E FISTS #11469 SKCC #1027 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/
Re: [digitalradio] Re: Pactor versus Olivia
Thanks for the suggestion Dave and I'm glad you liked my modest proposal. In fact I have an XSLT transformation I can apply to weather.com which is invoked via a command-line macro which inserts the current temperature from weather.com, so when people ask for WX that's what I give. Of course, you're right that QRZ.com should be providing the lookup service for people's macro definitions. That way when you settle in to use a new digimode program at the club station, you can get your macros loaded; and conversely, it can just send ^BRAG and the RX station can look it all up on QRZ.com to find the definitions. But why stop there, as you say? I'm reasonably sure someone's already done this (from the scores I see in the contest logs) but it should be possible to totally automate the RTTY contests. With wide-band SDR receivers (and transmitters for that matter) it ought to be possible to work the whole contest automatically. This same concept could easily be extended to macro-based ragchewing popular on PSK, with the digimode programs automatically doing search-and-pounce, macro exchange, and LoTW or eQSL QSLing.The mind boggles! Leigh/WA5ZNU Dave Bernstein wrote: Why stop there, Leigh? With the use of QRZ.com and weather.com to independently determine name, QTH, and weather conditions, you could encode many QSOs into a pair of callsigns plus one byte. 73, Dave, AA6YQ --- In digitalradio@yahoogroups.com, Leigh L Klotz, Jr. [EMAIL PROTECTED] wrote: Here's a modest proposal: compress most of the QSO the way the moonbounce modes do, by knowing what is expected at that point and expressing it in a few bits. For PSK, we could just standardize on macro names for a few things and the two modems can negotiate about whether to expand them on TX or RX. Instead of sending Your RST is 599 when the macro is RST the TX could just send ^RST and the RX modem can expand this into Your RST is 599. And if you send ^STATION ^BRAG the RX program can just print OM sent you a big list of his computer equipment. This might also eliminate a lot of the uppercase text as well... Leigh/WA5ZNU On Fri, 12 Jan 2007 1:02 pm, Rein Couperus wrote: -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 17:09:44 An: digitalradio@yahoogroups.com Betreff: RE: [digitalradio] Re: Pactor versus Olivia 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 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). -- 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 http://docs.yahoo.com/info/terms/ 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
Re: [digitalradio] Re: Pactor versus Olivia
The mind certainly does boggle. The day I start QSOing stations, that do that, and I know it, Im outta here. Its bad enough to hear the same MACRO 50 times in a row from someone, bragging about computer, software, antenna, rigs etc. etc. etc. ad nauseam. If it is important enough to say - say it - dont play it. In a contest, that would have to be a whole other type of entry. It certainly shouldnt be allowed to compete with real human contesters. Single computer ? By the way, 10 years ago, I had a program for my MFJ 1278B multi mode data controller that would almost come to that point. The info said it would copy signals, then call them and work them. It would then log the contact. Not in my shack - it wont. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: Leigh L. Klotz, Jr. [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Friday, January 12, 2007 11:06 PM Subject: Re: [digitalradio] Re: Pactor versus Olivia Thanks for the suggestion Dave and I'm glad you liked my modest proposal. In fact I have an XSLT transformation I can apply to weather.com which is invoked via a command-line macro which inserts the current temperature from weather.com, so when people ask for WX that's what I give. Of course, you're right that QRZ.com should be providing the lookup service for people's macro definitions. That way when you settle in to use a new digimode program at the club station, you can get your macros loaded; and conversely, it can just send ^BRAG and the RX station can look it all up on QRZ.com to find the definitions. But why stop there, as you say? I'm reasonably sure someone's already done this (from the scores I see in the contest logs) but it should be possible to totally automate the RTTY contests. With wide-band SDR receivers (and transmitters for that matter) it ought to be possible to work the whole contest automatically. This same concept could easily be extended to macro-based ragchewing popular on PSK, with the digimode programs automatically doing search-and-pounce, macro exchange, and LoTW or eQSL QSLing.The mind boggles! Leigh/WA5ZNU Dave Bernstein wrote: Why stop there, Leigh? With the use of QRZ.com and weather.com to independently determine name, QTH, and weather conditions, you could encode many QSOs into a pair of callsigns plus one byte. 73, Dave, AA6YQ --- In digitalradio@yahoogroups.com, Leigh L Klotz, Jr. [EMAIL PROTECTED] wrote: Here's a modest proposal: compress most of the QSO the way the moonbounce modes do, by knowing what is expected at that point and expressing it in a few bits. For PSK, we could just standardize on macro names for a few things and the two modems can negotiate about whether to expand them on TX or RX. Instead of sending Your RST is 599 when the macro is RST the TX could just send ^RST and the RX modem can expand this into Your RST is 599. And if you send ^STATION ^BRAG the RX program can just print OM sent you a big list of his computer equipment. This might also eliminate a lot of the uppercase text as well... Leigh/WA5ZNU On Fri, 12 Jan 2007 1:02 pm, Rein Couperus wrote: -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 12.01.07 17:09:44 An: digitalradio@yahoogroups.com Betreff: RE: [digitalradio] Re: Pactor versus Olivia 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 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). -- 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 http://docs.yahoo.com/info/terms/ Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist
Re: [digitalradio] Re: Pactor versus Olivia
SCS says that Pactor III is 4 times faster than Pactor II and the code would indicate such. Thus the raw channel throughput IS faster and the BER should be better. But as far as performance goes at varying SNRs will make a difference in throughput. At a -5 dB SNR on the KC7WW channel simulator KN6KB measured the throughput of Pactor I/II/II as about the same. At a + 10 dB SNR, the maximum throughput of Pactor I was measured as ~ 100 NetBytes/minute. Pactor II measures as ~3000 NetBytes/minute and Pactor III measures as ~11,000 NetBytes/minutealmost 4 times that of Pactor 73, Walt/K5YFW Do I correctly read this to mean that at high-noise low-signal strength conditions Pactor I, II, III are equal? Does that mean that the non-proprietary Pactor I that runs on a sound card is just as good as the proprietary and unaccountable Pactor II III under rough conditions? -- Thanks! 73, doc, KD4E ~~ Projects: http://ham-macguyver.bibleseven.com Personal: http://bibleseven.com ~~
RE: [digitalradio] Re: Pactor versus Olivia
Demetre, Correction SCS says...On an average channel, PACTOR-III is around 3.5 times faster than PACTOR-II. On good channels, the effective throughput ratio between PACTOR-III and PACTOR-II can exceed 5. PACTOR-III achieves slightly higher robustness at the low SNR edge compared to PACTOR-II. The URL to look at is http://www.scs-ptc.com/pactor.html and http://www.scs-ptc.com/download/PACTOR-III-Protocol.pdf Pactor III has several things going for it but also makes some considerations to be compatible with Pactor II and I that degrade the potential performance of Pactor III. Note in KN6KB's chart. The HF channel simulator used by KN6KB was the KC7WW Real-Time CCIR-520 Compliant HF Channel Simulator (http://www.johanforrer.net/simulr.htm). Simulated conditions includes several modes: pass through, flat fading, multipath For flat fading and multipath conditions, the Watterson model for simulating ionospheric effects is applied. This effectively simulates the compounded effects on several incident rays (typically two) due to influence of Earth's magnetic field, refraction in the ionosphere, and the dynamic motion of the ionosphere (Doppler). This results in the production of realistic amplitude fading and phasing effects with controlled statistical properties. Behavior of the model is controlled by user-supplied parameters for operating mode, fading rate, Doppler bandwidth. In addition, any level of Gaussian noise may be specified to achieve a particular signal to noise ratio (SNR). The figures in KN6KBs chart are an average of White Gaussian Noise, Multi-path Good (conditions), Multi-path (poor conditions) and Flat Fading. Again, note that above -5 dB SNR, the only difference that KN6KB shows is a change in throughput. The BER is not addressed. To achieve the higher thoughput of Pactor III, the number of tones (carriers/sub-carriers) is increased at the expense of a wider bandwidth...500 Hz for Pactor II and a maximum occupied bandwidth: 2.4 kHz @ -40 dB, audio passband: 400-2600 Hz (at Speed Level 6). SCS's use of Huffman and pseudo Markov coding (can be considered as double Huffman coding) is interesting and may be something that other coders may want to look at. Additionally the use of CCIR-CRC16 is nice. While ARQ is nice, it does have a transmission distance limit of 40,000 km. However for most, this is not a problem unless you are primarily going to use the mode for short haul NVIS operation...even at the 20,000 km ARQ setting. Perhaps the inclusion of a pilot tone(s) and tones with some other form fix modulation would have made the mode better. Also, IMHO the frame format is mode complicated that it needs to be. However, the adaptive qualities of the mode make it valuable. The use of DQPSK in speed levels 6, 5, 4 are questionable in that for QPSK modulation, you have a -3 dB loss...so the question is do you gain more using QPSK or not? Would have adding more DBPSK tones and a doppler tone proved better. And it goes without saying that using a real Viterbi decoder with soft decision provides a good coding gain. The features of Pactor III are the results of the cooperative and concerted efforts of several individuals who were not simply writing code to see what they could come up with. Rather they had a specific goal or set of speculations to work toward. The combination of cooperative effort and specific outcome goals has made Pactor III a very successful HF data transmission protocol. With the opensource soundcard protocols commonly referred to on this list, it is a shame that there is not more cooperative and collaborative coding efforts and a consensus of what outcome specifications hams are looking for in an HF data modem. 73, Walt/K5YFW -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Demetre SV1UY Sent: Thursday, January 11, 2007 10:44 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Pactor versus Olivia --- In digitalradio@yahoogroups.com, DuBose Walt Civ AETC CONS/LGCA [EMAIL PROTECTED] wrote: Again, may I inject my 2 cents worth. SCS says that Pactor III is 4 times faster than Pactor II and the code would indicate such. Thus the raw channel throughput IS faster and the BER should be better. But as far as performance goes at varying SNRs will make a difference in throughput. At a -5 dB SNR on the KC7WW channel simulator KN6KB measured the throughput of Pactor I/II/II as about the same. At a + 10 dB SNR, the maximum throughput of Pactor I was measured as ~ 100 NetBytes/minute. Pactor II measures as ~3000 NetBytes/minute and Pactor III measures as ~11,000 NetBytes/minutealmost 4 times that of Pactor II. 73, Walt/K5YFW Hi Walt, Thanks for reply. As I understand it if I need the speed it is a very good idea to upgrade to PACTOR III. I have PACTOR I and II at the moment and I am very
RE: [digitalradio] Re: Pactor versus Olivia
If you looked at the PDF document of KN6KB's measurements, that is what is showes. The only difference between Pactor I, II and III is the throughput (NetByte/minute) at various SNRs. I can only assume that the BER or percent of errors ( zero errors?) was also the same. PIII+10 dB SNR +5 dB SNR 0 dB SNR -5 dB SNR Throughput 11,500 NB/min 9,000 NB/min4,000 NB/min200-300 NB/min PII Throughput 3,200 NB/min2,500 NB/min1,800 NB/min200-300 NB/min PI Throughput 900 NB/min 900 NB/min 600 NB/min 100 NB/min All these are what I see on KN6KB's chart. At each of the above SNRs the Pactor mode has a shown throughput. If need 9,000 NB/min at a +5 dB SNR, then you need Pactor III. But if you only need a maximum throughput of 800 NB/min at +5 dB SNR, then you only need Pactor I. Walt/K5YFW -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of kd4e Sent: Thursday, January 11, 2007 9:44 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Pactor versus Olivia SCS says that Pactor III is 4 times faster than Pactor II and the code would indicate such. Thus the raw channel throughput IS faster and the BER should be better. But as far as performance goes at varying SNRs will make a difference in throughput. At a -5 dB SNR on the KC7WW channel simulator KN6KB measured the throughput of Pactor I/II/II as about the same. At a + 10 dB SNR, the maximum throughput of Pactor I was measured as ~ 100 NetBytes/minute. Pactor II measures as ~3000 NetBytes/minute and Pactor III measures as ~11,000 NetBytes/minutealmost 4 times that of Pactor 73, Walt/K5YFW Do I correctly read this to mean that at high-noise low-signal strength conditions Pactor I, II, III are equal? Does that mean that the non-proprietary Pactor I that runs on a sound card is just as good as the proprietary and unaccountable Pactor II III under rough conditions? -- Thanks! 73, doc, KD4E ~~ Projects: http://ham-macguyver.bibleseven.com Personal: http://bibleseven.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
Re: [digitalradio] Re: Pactor versus Olivia
While this information does not seem to support the SCS claim of working way down to the minus teens of db S/N, it is interesting that in the old days Pactor 1 users claimed that they could get throughput when they could not even hear any suggestion of modulation. I never found this to be true, but then I never had any SCS products either. Having an SCS Pactor 1 modem on each end of a connection was supposed to work much better than with mixed or other brands of modems. Particularly because of the ability to do memory ARQ. One thing that seems to escape Pactor 3 users, is that even though it might work 3 to 5 times faster than Pactor 2, the bandwidth is about 4 or 5 times wider so there is no real benefit if you are comparing occupied space to bandwidth. Sharing a finite and non-channelized service such as we radio amateurs use, having many small bandwidth users means more throughput for more users than one large bandwidth user at a time. 73, Rick, KV9U DuBose Walt Civ AETC CONS/LGCA wrote: If you looked at the PDF document of KN6KB's measurements, that is what is showes. The only difference between Pactor I, II and III is the throughput (NetByte/minute) at various SNRs. I can only assume that the BER or percent of errors ( zero errors?) was also the same. PIII +10 dB SNR +5 dB SNR 0 dB SNR -5 dB SNR Throughput 11,500 NB/min 9,000 NB/min4,000 NB/min200-300 NB/min PII Throughput 3,200 NB/min2,500 NB/min1,800 NB/min200-300 NB/min PI Throughput 900 NB/min 900 NB/min 600 NB/min 100 NB/min All these are what I see on KN6KB's chart. At each of the above SNRs the Pactor mode has a shown throughput. If need 9,000 NB/min at a +5 dB SNR, then you need Pactor III. But if you only need a maximum throughput of 800 NB/min at +5 dB SNR, then you only need Pactor I. Walt/K5YFW
RE: [digitalradio] Re: Pactor versus Olivia
Well I can't hear a CW signal at a -5 dB SNR. Can you? But I don't think minus teens...but that is what some of the newer PSK modes claim. The only thing that will really kill or stop Pactor is excessive amounts of doppler or until the detector can no longer decode the signal. You are actually making a case for RF footprinting. You want to see what the throughput is for bandwidth unit. We could measure it in Hz or KHz. 20 cps at 1 KHz is .04 cps/Hz (MT63-1K RAW). 5 cps at 100 Hz is also 4.5 cps is .05625 cps/Hz (PSK31). But when decoded, MT63 is almost 100% error free and PSK31 can have up to 10% errors. So it not all just about throughput, its about the overall robustness of the mode to include your requirement for how much error free copy you want. You are going to get many few errors with Pactor III than PSK31. If you used ARQ and something else to to the the BER of PACTOR III, you might find that the throughput was less than 5 cps. Walt/K5YFW -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of KV9U Sent: Thursday, January 11, 2007 2:31 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Pactor versus Olivia While this information does not seem to support the SCS claim of working way down to the minus teens of db S/N, it is interesting that in the old days Pactor 1 users claimed that they could get throughput when they could not even hear any suggestion of modulation. I never found this to be true, but then I never had any SCS products either. Having an SCS Pactor 1 modem on each end of a connection was supposed to work much better than with mixed or other brands of modems. Particularly because of the ability to do memory ARQ. One thing that seems to escape Pactor 3 users, is that even though it might work 3 to 5 times faster than Pactor 2, the bandwidth is about 4 or 5 times wider so there is no real benefit if you are comparing occupied space to bandwidth. Sharing a finite and non-channelized service such as we radio amateurs use, having many small bandwidth users means more throughput for more users than one large bandwidth user at a time. 73, Rick, KV9U DuBose Walt Civ AETC CONS/LGCA wrote: If you looked at the PDF document of KN6KB's measurements, that is what is showes. The only difference between Pactor I, II and III is the throughput (NetByte/minute) at various SNRs. I can only assume that the BER or percent of errors ( zero errors?) was also the same. PIII +10 dB SNR +5 dB SNR 0 dB SNR -5 dB SNR Throughput 11,500 NB/min 9,000 NB/min4,000 NB/min200-300 NB/min PII Throughput 3,200 NB/min2,500 NB/min1,800 NB/min200-300 NB/min PI Throughput 900 NB/min 900 NB/min 600 NB/min 100 NB/min All these are what I see on KN6KB's chart. At each of the above SNRs the Pactor mode has a shown throughput. If need 9,000 NB/min at a +5 dB SNR, then you need Pactor III. But if you only need a maximum throughput of 800 NB/min at +5 dB SNR, then you only need Pactor I. Walt/K5YFW 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
Re: [digitalradio] Re: Pactor versus Olivia
I have seen the claim for a good operator able to copy down to about -15 db S/N for CW operation. Some of the digital soundcard modes are supposed to be able to still have throughput down around -15 depending upon other factors such as doppler, ISI, etc. Using Multipsk, and I don't know how accurate this is, I can at least copy down to at least -10 with CW according to the readout display on S/N ratio, but even though I am over 60, my hearing is still quite good. I would not be willing to make too close a comparison between an ARQ and non-ARQ mode, but the footprint numbers were posited by Rick, KN6KB in his RFfootprints Powerpoint presentation. In comparing different modes, he claims that P3 is the superior mode, even to RDFT which he used to develop the SCAMP mode. He uses a spacing of 200 Hz between signals and that may or may not be entirely fair since the really narrow modes can work a lot closer than that from my experience. He comes up with a calculation of KHz-seconds by dividing the bandwidth by the characters per second, thus: MT63 2.2 KHz/20/ch/sec = 110 KHz-sec PSK31 .25 KHz/4 ch/sec = 62 HF Packet 1.7 KHz/37 ch/sec = 46 Pactor1 .55 KHz/20ch/sec = 28 RDFT2.2 KHz/97 ch/sec = 23 Pactor 2 .7 KHz/50/ch/sec = 14 Pactor 3 2.4KHz/225 ch/sec = 10 Of course this assumes everything is flowing perfectly and under most conditions some of the modes will seriously degrade, particularly HF Packet. MT-63 and PSK31 would stay at the same rate until they fail to get through. At that point, the Pactor modes would have slowed down to a fraction of their high speed and their numbers would not look as good. Perhaps they would move into the 30 to 60 range? At only 5 cps for a wide mode like P3 (but narrower at the slower speed levels at maybe 2000 Hz including a guard band), that would be 2000/5 = 400 KHz-sec and be extremely poor. Even at 20 cps, P3 would not have a favorable footprint anymore. 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 DuBose Walt Civ AETC CONS/LGCA wrote: Well I can't hear a CW signal at a -5 dB SNR. Can you? But I don't think minus teens...but that is what some of the newer PSK modes claim. The only thing that will really kill or stop Pactor is excessive amounts of doppler or until the detector can no longer decode the signal. You are actually making a case for RF footprinting. You want to see what the throughput is for bandwidth unit. We could measure it in Hz or KHz. 20 cps at 1 KHz is .04 cps/Hz (MT63-1K RAW). 5 cps at 100 Hz is also 4.5 cps is .05625 cps/Hz (PSK31). But when decoded, MT63 is almost 100% error free and PSK31 can have up to 10% errors. So it not all just about throughput, its about the overall robustness of the mode to include your requirement for how much error free copy you want. You are going to get many few errors with Pactor III than PSK31. If you used ARQ and something else to to the the BER of PACTOR III, you might find that the throughput was less than 5 cps. Walt/K5YFW
