Andy, I should point out that the High and Low latitude simulations are about the worse one can expect in terms of signal distortion. The timing delays and signal spread are what you might see during a magnetic / ionospheric storm. As you know, the polar paths are usually the worse.
There are so many variations between the quite ionosphere and severely disturbed that testing lots of different combinations with the simulator would be very time consuming. I went the 'severe' route to save time and show what modes would be useful under the worse conditions. The mid-latitude disturbance is much less severe than polar paths and the simulator shows how the majority of digital modes survive with lower signal spread and shorter path delays. Some modes start showing decode problems with only a slight (agitation) of the refracting layer and it's interesting to watch. I'm going to add a few modes for NVIS and hopefully shed some light on what works. Multi-path timing delays between the direct path and sky wave are said to be as high as 20ms with NVIS. My guess is that some modes will not print at all with timing issue of that magnitude. Tony, K2MO ___________________________________________ Ionospheric Path Simulations for Amateur Radio Digital Modes All SNR figures measured through 3KHz band pass filter. Sensitivity Test - Direct Path (no ionospheric disturbance) Minimum SNR for 100% decode Jason Turbo (Fast)..........-25db Contestia 500/32............-15db DominoEX-4 ..................-15db FEC-31.......................-15db THROBX-4......................-15db MFSK16...........................-14db THOR11...........................-14db RTTYM**...........................-13db Contestia 500/16............-13db CW 20 WPM...................-13db*** THOR16...........................-12db Olivia 500/16 ................. -12db MFSK31*........................-12db Olivia 500/8.....................-10db PSK31............................ -10db DominoEX-11...................-8db MT63 1K............................-8db Olivia 500/4...................... -8db PSK63..............................-7db Feld Hell............................-7db RTTY 45............................-5db * MFSK 31.25 baud. MMVARI Software. ** Intermittent decode problem with RTTYM regardless of SNR *** Subjective - speed dictates SNR ______________________________________________ Sensitivity Test - Direct Path -12db SNR (no ionospheric disturbance) Percentage of decode for modes with SNR threshold above -12db Olivia 500/8.... ...................90% Olivia 500/4........................90% DominoEX 11....................90% PSK31................................90% PSK63................................20% Feld Hell............................readable MT63 1K...........................no copy RTTY 45 baud..................no copy _______________________________________________________ Sensitivity Test - Direct Path (no ionospheric disturbance) Percentage of decode for modes with SNR threshold above -15db MFSK16.......................95% Contestia 500/32.........95% Olivia 500/16...............90% Thor11..........................80% RTTYM..........................80% Contestia 500/16.......<50% DominoEX 11bd........<50% Olivia 500/8.............. <50% MFSK31....................<50% PSK31........................<50% Feld Hell......................No Copy MT63...........................No Copy Olivia 500/4................No Copy PSK63........................No Copy RTTY 45......................No Copy THOR16......................No Copy _______________________________________________________________ High-Latitude Moderate Disturbance - 3ms path delay - frequency spread 10Hz - SNR -8db) Contestia 500/16........100% CW 20 WPM...............100% MFSK16......................100% MFSK31**...................100% Olivia 500/16...............100% Olivia 500/8..................100% RTTYM 500/32.............100% Olivia 500/4....................90% Feld Hell..................... ...90%* ThrobX-4........................70% DominoEX 4bd..........No Copy DominoEX 11bd........No Copy FEC-31................No Copy PSK31.........................No Copy Jason Turbo (fast)............No Copy PSK63.........................No Copy RTTY45........................No Copy THOR-11.....................No Copy THOR-16.....................No Copy MT63............................No Copy *diffuse print - readable ** MFSK 31.25 baud MMVARI Software. _______________________________________________________ High-Latitude Disturbed - 7ms path delay - frequency spread 30Hz - SNR -3db ) Contestia 500/16.......100% CW 20 WPM..............100% Olivia 500/16..............100% Olivia 500/8.................100% Olivia 500/4..................95% RTTYM..........................95%** MFSK31...................... 90% MFSK16.......................75% RTTY..............................40% DominoEX-4..............no copy FEC-31...................no copy Jason Turbo (Fast)........no copy MT631K......................no copy PSK31........................no copy PSK63........................no copy Thor-11.......................no copy ThrobX-4....................no copy Feld Hell.....................readable * * diffuse print - readable ** Intermittent decode problem with RTTYM ________________________________________________________ Mid-Latitude Disturbed - 2ms path delay - frequency spread 1Hz - SNR -8db) Contestia 500/16.......100% MFSK16.....................100% Olivia 500/16..............100% CW 20 WPM................90%* DominoEX 4bd............90% Feld Hell........................90% MFSK31 ....................90% MT63 1K.......................90% Olivia 500/8..................90% Olivia 500/4..................90% RTTYM 500/32.............90% ThrobX-4.......................90% DominoEX 11bd..........80% Thor-11..........................80% FEC-31...........................70% Thor-16..........................70% PSK31...........................70% PSK63...........................50% Jason Turbo (Fast)..............35% RTTY45.........................20% * Missing Morse elements due to fading ______________________________________________________________ Low-Latitude Disturbed - 6ms path delay - frequency spread 10Hz - SNR -8db) Contestia 500/16.....100% MFSK16...................100% MFSK31...................100% Olivia 500/16............100% RTTYM 500/32..........100% CW 20 WPM..............90% Olivia 500/8................90% Olivia 500/4................90% Throbx-4......................70% Feld Hell....................Poor Copy* DominoEX 4bd .......No Copy DominoEX 11bd......No Copy FEC-31.....................No Copy Jason Turbo (Fast).........No Copy MT63 1k....................No Copy PSK31......................No Copy PSK63......................No Copy RTTY45.....................No Copy Thor-11bd.................No Copy Thor-16bd.................No Copy * Characters diffuse difficult to read. Readability improves with increased SNR
