As Doug Smith has pointed out, the group delay issue on amateur gear can be challenging, even with training. The ionosphere is very unforgiving. Any tests you can do would be great. Have you considered discussing this with the Digital Voice Working Group at ARRL? They have gone through quite a bit of review on this and have also criticqued several different digital voice protocols, some of which can be used for either voice or data.
You are probably already aware that ARRL publishes committee reports under the announcements part of the arrl web site. Then you can look for updates by year on the Technology Task Force or working group reports HSMM, Digital Voice, SDR, etc. I was listening to W4LDE and WN3C on Olivia just now. In fact they were just signing off when I started writing this message and are wondering if anyone has had problems with using Olivia with the faster baud rates on 30 meters as they were experiencing a few minutes ago when they were using the 8-500 mode. I was copying both stations fairly well until signals got weaker on one of them. They switched to 16-500 with a significant improvement for them and for me to copy them as well. However, Olivia is under 20 wpm in that mode and is excruciating slow from my perspective. 73, Rick, KV9U Mark Miller wrote: >Rick, > >Yes group delay is an issue, but with adaptive training this too can be >overcome. Sound cards, or external modems using DSP or preferably FPGA's >would be a fine compliment to most amateur gear. The SDR (software defined >radio) that Jose mentioned will be the best solution going forward for more >exotic modems. These modems would be an integral part of the radio. > >I was looking for a good way to test group delay, and was thinking of >generating an FM signal with 3 to 5 KHz deviation and looking for an >envelope at the output of the receiver. Does that sound ok? The signal >generator is an HP 5640B. > >73, > >Mark N5RFX > > > >>Another thing that I came across in my web searching was that amateur >>equipment generally has group delays that make it difficult to even >>employ some of the modems we have been discussing. >> >> > > > >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 > > > > > > > > > > > > > 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/
