REF: http://www.mail-archive.com/digitalradio@yahoogroups.com/msg05238.html Re: [digitalradio] Why PACTOR for WL2K ? KV9U Fri, 26 May 2006 21:26:45 -0700 I may be able to shed some light on this. The original Aplink system that many of us used, starting in the 1980's, migrated from Amtor to Pactor and Clover II with the Winlink system. Amtor, even though an ARQ mode, had errors sent when conditions were deteriorating. This would send incorrect data into a BBS system and make things very difficult to proceed. Eventually, due to what was believed to be much slower operation with Clover II, they abandoned that mode after a number of years of use. It seems that this may have been unfortunately due to some software glitch that made it appear to work much slower than Pactor, but the decision was made and Pactor was made "the" mode for HF. By 1995, Pactor 2 came on the scene so Pactor modes became much faster than any other amateur ARQ mode. By the time things transitioned from Winlink (amateur radio networking) to the current Winlink 2000 (hybrid which is primarily an internet based system that has HF and VHF connectivity to amateur radio), Pactor 3 was the next step up in speed, although with a much larger footprint. Winlink 2000 is not really what I would call designed for emergency use. It is more applicable for casual ham to non-ham communications that are not critical. However, it can have utility in some cases, particularly if you need to send e-mail to non-ham contacts and you have large amounts of data and even attachments. Even then, much of the routing would be via VHF/UHF and not HF unless you had a severe widespread disaster or were remote from a Telpac connection. Since very few hams have this capability and most will never buy a $1000 modem for the rare case when it might be needed. The ARRL Board of Directors have not selected any particular system as the ARRL system, but at this time Winlink 2000 is the only thing available and has become the default system. The BOD has directed the ARRL to develop enhancements to the system and interoperability. JNOS2 has been greatly enhanced and can do some of the Winlink 2000 connectivity as well as the normal JNOS type of connections, so there are some alternatives. The Winlink 2000 system of multiple servers is complicated, but it makes the system more user friendly and takes care of e-mail addresses no matter where you connect into the system. Another alternative system is the PSKmail system developed in Europe however this system only operates using the Linux OS so is not likely to be very popular here in the U.S. for now. The ideal would be to move to more interoperability so the weaknesses of the systems can be compensated for by multiple ways to route traffic. My understanding is that the long term goals of Winlink 2000, would also include the ability to provide HF forwarding when everything else fails. While this is unlikely, it is something that some of us feel has to be in place to have a truly viable emergency communications system. The Winlink 2000 programmer did extensive development several years ago and culminated in the initial SCAMP mode. For some reason he did not understand that the RDFT protocol that was formerly used by SSTVers, needed around a 10 db S/N ratio to work. Somehow, it was thought that this mode could work down to near 0 db S/N, but clearly this was not possible. Also, it uses a very high baud rate of 122 and this can be problematic for many HF conditions. SCAMP did have two major new findings: First, the proof of concept that channel busy detect software could be developed and would work with any type of modulation including a dead carrier. Up until then, there were those who said this was not possible. But it really does work well. Second, that it is absolutely possible to develop a powerful ARQ mode that can use pipelined processing so that you can be receiving the incoming data at the same time that you are processing the last packet behind the scenes. This is highly significant in my view and hopefully the amateur digital community will progress someday toward having programmers who have the ability (and of course interest) to create an ARQ HF mode for sound cards. So far there just has not been the interest or the time to do this by the handful who have this ability but we can hope. The time line for further development has been delayed tremendously considering that SCAMP development ended just about one year ago. The beta software had timers that rendered the software unusable after last summer. The Winlink 2000 system is owned by only a few hams and they have tight control of the software so it is nothing like collaborations you see with Source Forge or open source which is more in the spirit of amateur radio. But Rick, KN6KB, has indicated that he will eventually place the SCAMP mode, or at least parts of it in the GPL. After all, some of the components are from Linux and the GPL although Winlink 2000 does not support Linux at this time. The bottom line is that amateur radio desperately needs a true ARQ error free sound card mode that is adaptable to the varying condition of HF and other than one ham programmer at one time attempting the ARQ MT-63, there doesn't seem to be much interest. Most of the programmers are more interested in developing keyboard modes and they have done a very good job considering all the choices we now have. Would love to hear of any on-going programming for HF ARQ sound card modes so if anyone does this or knows anything about it, please let us know. 73, Rick, KV9U Andrew O'Brien wrote: >I'm not debating PACTOR operations or the utility of the mode, just >wondering why "they" chose PACTOR as the mode for emergency >communications on HF via WL2K/Airmail ? I'll include the ARRL in the >"they" since they have endorsed the concept. > >The ideas behind WL2K seems to be extremely well thought out (in the >most part) but it seems to me that one part of the history of hams in >emergency communications ....is the simplicity of the process and >availability. ( e.g. most hams can get on the air in a hurry, have >alternative power sources, and there are plenty of us). The law of >averages would indicate that of the thousands of hams, a few hundred >would surely get on the air in a real emergency situation. > >If I am correct, WL2K HF system is dependent on PACTOR. PACTOR is a >proprietary system that is extremely expensive , not something >available easily to all hams. Reliable hardware for PACTOR II and III >is more expensive than a new HF rig these days. > >Would it not have been "better" to choose a system that is not >proprietary and thus more likely to be included in the many public >domain/free software applications? Since sound cards are used as a >modem these days, and almost everyone has a sound card, would it not >have been better (or more practical ) to develop something that works >with the WL2K/AIRMAIL concept that all have can access? > >I am aware that VHF and packet radio may be fairly well developed as >an alternative to PACTOR/HF reliance. However, I have seen the >vulnerability of VHF systems in rural areas and really feel that an HF >system, not dependent on expensive , minority owned, systems ...is >needed. Yes, I KNOW, we can all do CW when we have to but I am >talking about an organized system (like W2LK) but one that encompasses >as many hams as possible. > > >-- >Andy K3UK >Fredonia, New York. >Skype Me : callto://andyobrien73 >Also available via Echolink > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) SPONSORED LINKS Ham radio Craft hobby Hobby and craft supply -------------------------------------------------------------------------------- YAHOO! GROUPS LINKS Visit your group "digitalradio" on the web. To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. -------------------------------------------------------------------------------- [digitalradio] Why PACTOR for WL2K ? Andrew O'Brien Re: [digitalradio] Why PACTOR for WL2K ? Steve Hajducek [digitalradio] Re: Why PACTOR for WL2K ? Dave Bernstein Re: [digitalradio] Re: Why PACTOR for WL2K ? list email filter Re: [digitalradio] Re: Why PACTOR for WL2K ? doc Re: [digitalradio] Re: Why PACTOR for WL2K ? list email filter [digitalradio] Re: Why PACTOR for WL2K ? Dave Bernstein Re: [digitalradio] Re: Why PACTOR for WL2K ? list email filter [digitalradio] Re: Why PACTOR for WL2K ? Dave Bernstein Re: [digitalradio] Why PACTOR for WL2K ? KV9U Re: [digitalradio] Why PACTOR for WL2K ? Kevin O'Rorke Re: [digitalradio] Why PACTOR for WL2K ? KV9U [digitalradio] FS Byterunner PCI 8 port serial card Saad Mahaini [digitalradio] FS MFJ-1272BX Mic/TNC Switch Saad Mahaini Re: [digitalradio] Why PACTOR for WL2K ? John Becker Re: [digitalradio] Why PACTOR for WL2K ? [EMAIL PROTECTED] Re: [digitalradio] Why PACTOR for WL2K ? John Becker Re: [digitalradio] Why PACTOR for WL2K ? 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