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
Re: [digitalradio] PSK500 **Minimum SNR - Fast vrs. Slow PSK Modes**
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
Re: [digitalradio] PSK500 **Minimum SNR - Fast vrs. Slow PSK Modes**
- Original Message - From: Dave Sparks dspa...@pobox.com To: digitalradio@yahoogroups.com Sent: Saturday, October 24, 2009 7:55 PM Subject: Re: [digitalradio] PSK500 **Minimum SNR - Fast vrs. Slow PSK Modes** 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. I should hame mentioned Olivia 64/2000, instead. I seem to remember that FLARQ won't work with Olivia for some reason, but I'm not sure about jPSKmail. Reading the specs on these modes, they actually sound a lot like spread spectrum. -- Dave Sparks AF6AS Riverside, CA, USA (DM13gw)
