Brian, It depends upon what you, or the average ham, are looking for. If you want to do contesting, and if the inertia stays with RTTY, then that is what will remain as a popular mode. A couple of decades ago, many of us found RTTY to be quite interesting and even built TU's to get on HF.
Then along came the boxed hardware/firmware ARQ modes of Amtor and then Pactor and Clover II and moved the bar. This made it possible for nearly 100% data transmission accuracy for the first time on amateur radio. While you would not use these connected modes for contesting, due to the slow exchange, they worked well for messaging and casual contacts. These modes were fairly expensive and not widely adopted, but they were a niche interest, no different than other niche interests in our amazingly broad hobby. More recently, the sound card modes caused the next big change in digital radio communications. In terms of sensitivity, RTTY is more limited. It can certainly go below zero dB S/N, but some of the newer digital modes can go far below that. So where you would get no communication at all with RTTY, you would have solid print with say, PSK31 or MFSK16. The extra baggage of interleaving, coding, redundancy, etc., allow for much improved robustness, far beyond what RTTY can do. Now we have the next big change which is sound card ARQ technology. This was first implemented with SCAMP about three years ago but abandoned by the Winlink 2000 developer. Not long ago, one ham was able to develop the PAX mode and then the PAX2 mode which gave us an inkling of what is possible with sound card and digital ARQ. That same ham has been able to use an older technology, using the 8FSK125 waveform from ALE and adapt it for ARQ with the full ASCII character set and make it available in a multimode software program at no cost. Then he was able to go even farther and develop an 8FSK50 mode (ALE 400) that is much narrower, but is also much more sensitive and robust and is more appropriate in the text digital portions of the ham bands. It sounds as if you are not very supportive of, or even interested in emergency communications, however, there are many of us who find that part of ham radio to be the most interesting and we are always on the look out for modes and equipment that are inexpensive and therefore would be used by other hams and allow us to provide better communications than we have thus far been able to do. You are right that we do need to focus on a common denominator for emergency communications. We continue to do this through tactical HF and VHF voice which is an absolute must. But some believe we can and should do more than the minimum and thus we look to new technologies to do things that we could not do before. RTTY is definitely not one of those technologies, but ARQ sound card modes can be. There are so many new modes and technologies competing at the same time (and likely more to come) that it will take some years for radio amateurs to sift and winnow and find those that have the right mix of cost, adoption, and use. But I think it is fair to say that it is also the most exciting time for the digital modes and related technologies since I was first licensed in 1963. 73, Rick, KV9U Brian A wrote: > As one who uses digital only to > communicate and DX, I'm not sure what all this buys me-- or the > average ham. > > For starters: > 1) Using a 200 Hz filter instead of 400 or 500 Hz filter gives a 3db > S/N ratio improvment-- PSK or RTTY. It's guaranteed. > 2) There are actually many people to talk to. > 3) 100% copy is not needed in most QSO's. If someone's rig displays > on the screen as a TS-851 instead of a TS850, it really doesn't > matter. Similarly with eyeball QSO's with someone, nobody "copies" > all words 100%. Let's face it, even with a few errors stuff relayed > by ham radio is miles ahead in accuracy compared to what comes out > from the mass media. > 4) One can alraady work stations down to the noise floor. Actually, > I've had many RTTY contacts below the noise floor by augmenting the > print with aural copy of calls/reports. > > In other words, all the extra baggage (bandwidth) is generally just > extra weight with no robust benefit. Sure some selected applications > may need it. Until we find a way to access extra frequency blocks in > some parallel universe, narrower is better. > > Unfortunately, a lot (but not all) of the hype about "emergency" > communications is just a smoke screen to forward particular personal > agendas. If ham radio existed to keep the price of pork high, you'd > have people saying their invention does that too. > > It is interesting to note that so much of this stuff is hyped as THE > ANSWER to emergency communications. I see the same claim by the AMSAT > people and many other groups for their modes (e.g. D*). Of course > each isn't. Each is one of many possibilities. The more obsure you > make the mode, the fewer people will be proficient at its use. The > smaller the pool of emergency repsonders we would have. Hype isn't > the answer to expanding the pool. It's got to be accepted by a wide > swath of users. It has to "age" for many years in the pot of real > experience. Instead we're seeing the "digital flavor of the week". I > guess after 40 years of hype for various hame radio adgendas, I've > grown tired of hearing them, become a skeptic and rather cynical of > "new and improved". > > How about a shift in paradigm? Look around and see what modes most > people use and adopt that? It doesn't have to be just digital! > Wouldn't that provide the largest possible pool of responders and > equipment? Realize that our contribuition is for the window of time > between time zero of an event until when the official channels get > running. One is dealing with maximizing the probability of having > trained ham radio personnel and equipment actually at or near a > particular location. It seems that big numbers matter. > > Interesting comment about the usage of digital freq's there. The PSK > area of the digital 20M band is absolutely wall to wall with stations > over here. 40M is similarly crowded especially at night with PSK and > RTTY. I can't imagine trying to use a wide IF filter on 40M for any > digital mode. > > > 73 de Brian/K3KO > >
