If you go much above a 2 Khz bandwidth, you're going to start ruling out a lot of rigs that don't have the audio bandwidth to pass that wide of a signal. I wonder how PSK 2000 would compare with esisting modes, such as Olivia 32/2000 and MT63 at 2 Khz bandwidth.
BTW, your figures seem to indicate that the product of gain times bandwidth is roughly a constant in an entire HF system, just as it is in a transistor amplifier. --- Dave Sparks AF6AS ----- Original Message ----- From: Tony To: digitalradio@yahoogroups.com Sent: Saturday, October 24, 2009 4:36 PM Subject: Re: [digitalradio] PSK500 **Minimum SNR - Fast vrs. Slow PSK Modes** Andy, > Thanks Rein. Is there a PSK2700 ? That would certainly get Peter > Martinez's eyes > rolling. I agree, he would roll his eyes but the throughput would be lightening fast! I tried to get Mixw to run at very high speeds a while back just to see if it would work. It did, but it seems to stop printing at PSK625. The path simulator indicated that the minimum signal-to-noise threshold increased by roughly 3db each time the word-per-minute / baud rate was doubled (see below). It would be interesting to test PSK63 vs. PSK625 on VHF to see if that wide 10db difference shows on-air. It should take 10 times the power to maintain the same throughput according to the simularor. Difficult to prove on HF with all the variables; bandwidth is 2K-plus. Mode Minimum SNR PSK31............................. -10db PSK63................................-7db PSK125..............................-4db PSK250..............................-2db PSK500.............................+2db PSK625.............................+3db Tony -K2MO
