There is no other comparable system (hardware/software combination) to Pactor because no other mode is as adaptable and gets through under fairly poor conditions (which are very common on HF) but can still ramp up to reasonably good speeds when the conditions are excellent if you have P2 or P3.
SCAMP has the potential to compete with Pactor. At this point it is only a potential because: 1) The Winlink owners completely control who gets to do what and when with the WL servers. My understanding is that WL2K code is not shared with others and is only available to the selected stations as a remotely controlled download. I know that this is true with the non-published ARES-PMBOs. There have been additional requests to host SCAMP but they have been turned down at this time. Currently, there are only three SCAMP servers (PMBO's) and all are located the U.S. There is a strong desire to maintain the current Pactor modes since that is what most of the users have now and I suspect will have even a decade from now. Years ago the Winlink system (all RF, not the same thing as the Winlink 2000 system of today) was able to handle up to three different modes, Amtor, Pactor I, and Clover II on many of the servers although it was a pain from the setup descriptions. RTTY Digital Journal used to have info on this. So it is possible to do. 2) If we don't get the bandwidth to expand semi-automatic stations wider than 500 Hz, it would be difficult to find enough room on HF for connecting to automated servers due to the narrow subbands for the wider modes. Pactor II can of course still operate, as it has for many years since it is under 500 Hz. SCAMP would be very limited since it requires close to a voice width channel. In terms of MT-63 and MFSK16, I have asked the principal current WL2K developer about incorporating a much more robust, albeit, very slow speed fall back transmission into SCAMP. This would pass traffic even when Pactor would be inoperative. But he indicated that he looked at these and did not find them acceptable. Apparently the speed was the concern. The use of some new RDFT protocols along with the inclusion of even some WinDRM code gives me great concern. The baud rates are still at a high 122 with RDFT and I could not convince him to use something around 60 or less:( And WinDRM is not noted for its weak signal ability either. This may prove to be unfortunate since multipath distortion, especially on the lower bands, is the norm and high baud rates make it harder to get the signal through. It is also true that for random noise (AWGN) the shorter symbols (higher baud rates) can actually work better. This is why Pactor modes are so robust. They picked a compromise speed of 100 baud for the lowest baud rate and then use significant amounts of error correction to make it work better than you would expect for such a high baud rate. By the way, Paul, K9PS, is still working on an ARQ version of MT-63 but we have not heard anything for a few months now. If you could "pipeline" MT-63 like Rick, KN6KB did for SCAMP, I think you would have a reasonably good mode for weak signals. While there are apparently some folks who honestly believe that you can use a non-error free mode for messaging, I am not one of them:) 73, Rick, KV9U -----Original Message----- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Joel Kolstad Sent: Thursday, June 16, 2005 09:44 To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Question about HF-email OK, I'll re-phrase that as Pactor III just being "arguably a very robust and fast mode." :-) Thanks for the info; hopefully SCAMP will take a look at MT63's modulation scheme (if they haven't already). ---Joel -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.7.3/15 - Release Date: 6/14/2005 The K3UK DIGITAL MODES SPOTTING CLUSTER AT telnet://208.15.25.196/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> 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/
