Rick and all, Richard, G4HPE, hasn't been the only one using it...perhaps he has used it more formally in this paper on digital modes. However, Charles, G4GUO, has used it along with almost every manufacturer of hardware or software high-speed digital modems...especially those making MIL-STD/Fed STD/STANAG (NATO) modems.
Robustness certainly is not a new term. But one must qualify the level of robustness. The CCIRs have done this with their standards, i.e. CCIR for good and poor HF channels and at a specific SNR. Johan, KC7WW, in his evaluation of PSK31, et al modems, (Novel Robust, Narrow-band PSK Modes for HF Digital Communications http://www.johanforrer.net/hfpsk.htm) including MT63, used a robustness standard of -10 dB on a poor CCIR HF channel. KC7WW clearly indicated that there is "The Need for Simulation" (http://www.johanforrer.net/SIMULR/index.html) While several professional-grade channel simulators that allows real-time simulation of baseband HF channels are available on the market. These include units manufactured by Harris (RF-3460), Cossor (1250), Magnavox, and Signion Systems (http://www.signion.com/hfsim.htm), KC7WW developed his own. Additionally Moe Whearley, AE4JY, has produced software HF path simulator, http://www.qsl.net/ae4jy/pathsim.htm that could be used to test digital modes. To demonstrate the exceptional capabilities of these new digital modes, KC7WW subjected each to extremely poor, however, identical test conditions simulating ionospheric propagation test conditions consisting of two equal-power rays with 2ms differential path delay, 1 Hz Doppler frequency spread, played against Gaussian noise with SNR set at -10dB (3 kHz bandwidth). Keep in mind that the signal was not only weak, but it was also fading and had severe multipath distortion as well. A standard test text was used on all the modes KC7WW tested. Today most "robustness" claims or reports are for the greater part antidotal...not really scientifically obtained. To determine the REAL robustness of a mode, it must be tested against a standard. Walt/K5YFW -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 25, 2006 11:34 AM To: [email protected] Subject: Re: [digitalradio] Re: Best Mode for QRP? It seems that we have been using the terms robust and robustness for a few years. I know that SCS uses this terminology for their Pactor 2 and 3 systems. Perhaps we picked it up from their advertising? It could come from other sources such as G4HPE's digital mode comparison where he uses the term several times. If you don't call it robustness, then it seems to me that some other word would need to be used to describe the capabilities of some of the newer modes. After all, we would not use new modes unless they had some compelling reason and the most compelling to me is that the print is more accurate even with very difficult conditions and yet the throughput is at least adequate to satisfy the purpose of the tx. 73, Rick, KV9U Rusty Gate wrote: >Thanks Rick, >Sorry if it sounded a bit tongue-in-cheek was just about to take >off for cooper county for the weekend. Really the reason that I ask >is the in my 27 years in broadcasting and 2 way radio repair the >word robustness or in any form was never used. This must be a new >one. But then I still was a 28ASR machine for RTTY and a slide rule. >Yeah I know half the group just ask themself "what the hell is a >slide rule " Well kids it's a none electirc calculator. Still have >the one I used to take the frist class radio telephone test in front >of the FCC in 1970. > >Anyway where did that word come from and when was it frist to >used? > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
