Hi Rick, The other night I went through that PhD thesis you have posted on HfDec.
The main problems on HF, according to that author, are not AWGN but fading and multipath. He even indicated that the AWGN model is inaccurate that empirical measurements indicate the noise is Laplacian, which has a steeper roll off that Gaussian. He also indicated that did not seem to make much difference. We seem to be on the same wavelength <groan> with no interest in putting down any protocol but in looking at them objectively. ALE, Pactor, DominoEX, Mt63, and all the others are doing well in various ways. Given some theory and this practical experience how do we develop something that does even better overall. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -----Original Message----- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Saturday, September 22, 2007 11:35 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] ALE yes ... or no? ... I have been spending a LOT of time researching the studies of ALE and the standards from the company claims. Many of these are computer simulations and not real world tests. As one scientist put it, they had some modes that worked well with computer simulation but were completely useless when field tested. The one thing that you will find is that the high speed modes typically need a good strong, clear, moderate to low ISI signal. ... 73, Rick, KV9U
