[digitalradio] HF channel models?
Is there a source of channel models commonly used to develop HF protocols? I haven't been able to find a good model of (or even generally-accepted worst-case numbers for) multipath delay spread and doppler spread on cross-polar paths, for example, or SNR statistics (noise burst distributions, etc.) for long DX paths on the low bands. Failing models, does anyone have any measured data? The only information I've found is in Davies' Ionospheric Radio, (and its references) but it doesn't quite hit the spot. Thanks, Ed, N4II.
[digitalradio] ALE activity reports
Activity Report 14109.5 kHz ALE today K8HKW K7EK W1PID WA3MEZ W6CM VE5MU 73 Bonnie KQ6XA
[digitalradio] Most robust digi-mode with 200 to 600 bps ?
Question to the experts: What is the most robust digi-mode with a 400 to 600 bps raw capacity (or 200 to 300 bps fec capacity) ? Is a boosted psk variant the best coice or is mfsk capable of such rates ? Other options ? Background: Seems someone has developed a 200bps voice codec. It's a phoneme coder. The data rate and the description sounds plausible. I dont know if this will ever be available as open source for amateurs, but it would be intresting to estimate the possibilities of such a codec for DV (digital voice). Such a coder could probably beat analog ssb in terms of robustness in marginal conditions.
Re: [digitalradio] HF channel models?
Hi Ed, Murray Greenman (ZL1BPU) might have what you're looking for. Have you tried PathSim? http://www.qsl.net/ae4jy/pathsim.htm 73 Tony KT2Q - Original Message - From: dtmos [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, June 06, 2007 3:01 PM Subject: [digitalradio] HF channel models? Is there a source of channel models commonly used to develop HF protocols? I haven't been able to find a good model of (or even generally-accepted worst-case numbers for) multipath delay spread and doppler spread on cross-polar paths, for example, or SNR statistics (noise burst distributions, etc.) for long DX paths on the low bands. Failing models, does anyone have any measured data? The only information I've found is in Davies' Ionospheric Radio, (and its references) but it doesn't quite hit the spot. Thanks, Ed, N4II.
