> WHAT WE KNOW AT THIS MOMENT: > A computer will not work for a fast ARQ mode because > every time it does anything else that timing link is > lost.
Not true. The question is what you mean with speed. If it is an average data transfer speed, than it is certainly possible to write a very high speed HF ARQ modem using a common non real time operating system like Windows or Linux and sound card. If it is a turnaround time (interactivity, response times), than it would be harder. The following protocol http://sharon.esrac.ele.tue.nl/pub/linux/ham/pskmail/ARQ2.pdf may be not the best possible, but it certainly works for pskmail on Linux. It utilises one PSK63 channel. If you change the bottom layer to a four parallel PSK streams with the baud speed of RTTY and add some smart redundant coding and data compression, you will get a similar result to Pactor II modem. Why it has not been implemented yet? The answer is simple. It is a complex task that nobody seems to be willing to do for free. It is easier to build external box with the software burned into it, which is much harder to make a copy of it. To all the hams that cry about bad guys at SCS making lot of many on them. How about to establish a nadation to hire three experienced DSP programmers for three years to write a modern ARQ soundcard mode for us? Multiply 9 manyears by an income of a programmer in western countries. Then divide it by the number of modems sold by SCS. Is the price of the box reasonable now? So we have to thank Rein PA0R for his work on pskmail, that he gives us for free. 73, Vojtech OK1IAK 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) 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/
