Is there a way of getting the article for the group. It is very important. Thanks
Omar YK1AO (now operating under 6C60O commemorating 60 years amateur radio in YK-land) ----- Original Message ----- From: Rud Merriam To: digitalradio@yahoogroups.com Sent: Thursday, October 25, 2007 8:10 PM Subject: [digitalradio] QEX Article on HF Digital Propagation There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
