Patrick, > I for one would like to try different modes and compare them > under real conditions. There can be too many variables.
I agree, I think the simulator can tell a lot about mode performance, but it has it's limitations. It might be a good idea to test modes according to type. Seems fruitless to compare a mode that's known to be extremely sensitive and robust against the "average" chat mode. Good point about switching frequency when testing; need to mind the wide modes in the narrow band segments etc. There was a lot more activity along these lines when sound-card modes were first introduced. Wonder if anyone recalls digital beaconing? Station S59DOR had one on 10 meters that would transmit the different Hellschreiber modes. Macros allowed the software (IZ8BLY's Hellschreiber) to switch modes automatically. Have a screenshot of the beacon if anyone is interested. Glad to see the enthusiasm Patrick! It's the stuff that keeps the hobby alive. Tony, K2MO Kings Park, NY ----- Original Message ----- From: "Patrick Novak" <[EMAIL PROTECTED]> To: <digitalradio@yahoogroups.com>; <[EMAIL PROTECTED]> Sent: Friday, July 11, 2008 11:09 PM Subject: Re: [digitalradio] Re: KV9U - Mode Sensitivity / Robustness > Hi Tony and it is good to see your posting to the group. > > I for one would like to try different modes and compare them under real > conditions. There can be too many variables. I understand it is impossible > to do it exactly but how about this scenario: > > We will start a contact and send a short file in one mode, then switch to > a different mode (close/same frequency/band) and send the same file > again. > Try several modes and then compare the number of errors in each mode. > If we have a large sample set we will be able to make an educated guess at > the mode which performs best. > There could be a group or individual who will keep the results table, or > each or OF us (experimenters) will keep own statistics. > What do you think? What everybody thinks? > > regards es 73 > Patrick > VK2PN > > > > Tony wrote: > > Rick, > > >Has anyone compared Domino EX with the top modes that get > >through the worst conditions and, if so, what have you found? > > I've compared a variety of sound card modes for sensitivity and > robustness using an HF path simulator (see below). > > I first tested each mode for sensitivity by finding the lowest > signal-to-noise ratio that would still produce 100% decode. These were > direct-path simulations with no ionospheric disturbance. > > > For what it's worth, DominoEX 11 baud, had about the same sensitivity as > MT63 and Olivia 500/4. DominoEX 4 baud had about the same sensitivity as > MFSK16. > > Olivia 500/16/8 were more sensitive than DominioEX 11 as well; Olivia > mode sensitivity would increases with an increase in the number of tones. > > Things got interesting while testing for robustness with the ionospheric > simulator. The Domino EX modes fell short to the point where they would > not decode at all with certain disturbances regardless of SNR. > > The DominoEX modes seemed sensitive to frequency spread found on the more > disturbed ionospheric paths, especially polar and low-latitude paths. > > I think it's important to remember that these are simulations and on-air > testing may show different results. There are no static crash simulators > with Pathsim so it's hard to simulate things like mode recovery time etc. > > If anyone is interested in path simulation, it's important to normalize > the audio before it's feed into the simulator. Normalizing keeps the audio > at the same level so one mode is not any louder or weaker than another. > > Tony, K2MO > Kings Park, NY > > ______________________________________________________ > > > Sensitivity Test ( lowest SNR that will produce 100% decode) > (DIRECT PATH - NO IONOSPHERIC DISTURBANCE) > > RTTY 45................... -5db > Feld Hell.....................-6db* > DominoEX-11........ -8db > MT63 1K................. -8db > Olivia 500/4.............. -8db > Olivia 500/8..............-10db > PSK31................... -10db > Olivia 500/16 .......... -12db > MFSK16....................-14db > DominoEX-4 baud...-15db > > * Simulated quiet band condx. Good contrast between text and white > background. > > > ______________________________________________ > > Sensitivity Test SNR -12db > (DIRECT PATH - NO IONOSPHERIC DISTURBANCE) > > MFSK16.....................Perfect Copy > Olivia 500/16..............Perfect Copy > DominoEX 4 baud....Perfect Copy > Oivia 500/8..................90% > Olivia 500/4.................90% > DominoEX 11 baud...90% > PSK31.........................90% > Feld Hell......................Faint Text * > MT63 1K.....................No Copy > RTTY 45 baud............No Copy > > * Feld Hell somewhat readable at this SNR under extremely quiet condx. > > _______________________________________________________ > > Sensitivity Test SNR -15db (faint signal in waterfall) > > (DIRECT PATH - NO IONOSPHERIC DISTURBANCE) > > DominoEX 4bd..........100% Copy > MFSK16.......................95% Copy > Olivia 1K/32.................90% Copy > Olivia 500/16...............90% Copy > > > Olivia 500/8................. <50% > THE QUICK BROWN FOX :UMPS OB$[T,3AZY DOG > T.`8 dIC `"N FSX JUd VCR g&?GZY 1PaOlj/== BROWZ+_ > /|mu_S R pHB\7JY 9OG > > Olivia 500/4...................No Copy > > > DominoEX 11bd...............50% > tTHE QUICK BDOWN FOXGUMPSLiVER IE LA ' Y BCI > THQUICK) ROWN FOX JU S OVCu THE LAZY DOG > TH QUo OWN FN0 ZUMLx OGR THE tZY DOa? L > > PSK31...........................<50% > E QUIhK BRO FOs J.MPS OVEC THE s > -t( a OGTr �ITBRO N Ft uJU0PbtaVEXE LAZY t > OpHE uPIOK BROWN FtoMPS OT0R li0 LA rY Ctep > > MT63..........................No Copy > Feld Hell.....................No Copy > RTTY 45....................No Copy > > _______________________________________________________________ > > > High-Latitude Path Simulation > > (Moderate High-Latitude Disturbance, 3ms path delay, 10hz frequency > spread, SNR -8db) > > (3ms path delay, 10hz frequency spread, SNR -8db) > > MFSK16......................Perfect Copy > Olivia 500/16...............Perfect Copy > Olivia 500/8..................Perfect Copy > Olivia 500/4..................90% > Feld Hell........................90%* > DominoEX 4bd..........No Copy > DominoEX 11bd........No Copy > PSK31.........................No Copy > RTTY45........................No Copy > MT63............................No Copy > > * Text to background contrast marginal but readable. > > _______________________________________________________ > > > Mid-Latitude Path Simulation > > (Storm condition Mid-Latitude Disturbance, 2ms path delay, 1hz frequency > spread, SNR -8db) > > MFSK16......................Perfect Copy > Olivia 500/16...............Perfect Copy > Olivia 500/8..................90% > Olivia 500/4..................90% > DominoEX 4bd............90% > MT63 1K.......................90% > Feld Hell........................<90%* > > *Good text contrast, missing characters > > DominoEX 11bd > THE QUIRK BROWN FOX JUMPTYOFttT3G LAZY DOG > THE QROWN FOiRJUMPtJeoER TLAZY DOG > THE QUICK NNOWOXlrUMPS OVER ti8AZY DOG > > PSK31 > THe EaoICK BROWN F Jto c OTeR THE LAZY DOG > THE Q4Icš BROWN MOX p HMPS OVIRHE LAZY DOG > Tr4 QUICK BROWNa o e o JUMPS r -ER THE LY > > RTTY45 > XMXSPYUIVK BRGWN FOKGDUMHR KZ4 ZILAZYHDOG > OVZHE QUFKH?492,6FF JINQ QOCSKQ0/6&)'6 BMXDQ > NQ QUICK YBRTZNLFMY JUVHS OVER PHE )-+6 DOG > > ______________________________________________________________ > > Low-Latitude Path Simulation > > (Storm condition Low-Latitude Disturbance, 6ms path delay, 10hz frequency > spread, SNR -8db) > > MFSK16...................Pefect Copy > Olivia 500/16............Perfect Copy > Olivia 500/8..............90% > Olivia 500/4..............90% > Feld Hell....................Poor Copy* > DominoEX 4bd .......No Copy > DominoEX 11bd......No Copy > MT63 1k....................No Copy > PSK31......................No Copy > RTTY45.....................No Copy > > * Feld Hell letters were diffuse (spread) making it difficult to read. > > > > > > -- > ~~~~~~~~~~~~~~~~~~~~~ > Patrick VK2PN > QF56pe > Sydney Australia > > ------------------------------------ Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked Check our other Yahoo Groups.... http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/themixwgroup Yahoo! 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