Re: [digitalradio] Advantages of D-STAR Digital Voice Data
Rick - I've seen you mention these negatives about D-STAR several times on various lists so I've felt compelled to respond. I grew up in a rural area of Wisconsin similar to where you live. In a low density area of population is difficult to support many things out of the mainstream initially, including new technology. I currently live in the city of Chicago where a large population base makes many things possible that are not possible in a rural area. For example, I can literally walk down the street and go to a foreign film theatre, Argentinian restaurant, several Irish pubs, Thai restaurant, authentic Austrian coffee house, Wrigley field for baseball, Italian restaurant, Peruvian restaurant, Mexican restaurant, Cuban restaurant, Turkish restaurant, Guatamalan restaurnat, Persian restaurant, live theatres, etc. A short cab ride or drive and the list grows almost exponentially. Nearly none of these things are available in my hometown of 12,000 people in a county of 50,000. Since I don't believe you have actually used D-STAR yet and I have I will respond to your concerns about D-STAR: 1) I find the audio quality of D-STAR not only acceptable, but in many cases preferable to FM since it does not have the static pass noise that accompanies FM as the signal dimishes in strength. 2) One could have a philosophical argument about whether a digital voice radio should be able to switch to becoming a dedicated data radio at a higher data rate than D-STAR's low-speed data (950 bps). However the low-speed data built into EVERY D-STAR digital voice radio eliminates the need for a separate TNC or modem that you would need with an FM radio. Low-speed data that is concurrent with digital voice has been found to be very useful for sending GPS coordinates, text messages keyboard-to-keyboard exchanges. These are very useful in public service emergency activities. 3) Digital voice systems have been found to have a 15% greater effective range that FM at equivalent power levels due to the lack of path noise on digital voice. When digital voice becames garbled due to weak signal the FM signal would already be unusable due to path noise. 4) D-STAR radios cost about the same as FM VHF/UHF radio did 15 years ago when adjusted for inflation, but D-STAR radios do a lot more. We tend to forget or not realize that ham radio equipment has gotten very cheap over the last 10 years and has tracked the same reduction in consumer electronics prices, such as VCRs. 5) 35 years ago at the dawn of FM repeaters you could have made the same argument that no one owns an FM radio and you should stay on 2m, 6m or 10m AM simplex which were popular at the time very cost effective. But hams did spend more money on new crystal controlled FM radios once the repeaters went up saw the obivious benefits of repeaters. As D-STAR repeaters are going on the air the same thing is happening. 6) You could have used the same argument in the 1950s that SSB would make it so that most SWLs couldn't hear amateur SSB on their inexpensive AM receivers. There are a large number of existing analog FM repeaters that will be around for a very long time for scanner listeners to hear so there should be no concern about D-STAR displacing exisiting FM. In fact, all D-STAR radios also can do FM and most D-STAR repeaters implemented by groups do not displace existing FM repeaters. 7) Many clubs or groups who already operate analog FM repeaters are adding D-STAR repeaters are not replacing the existing FM repeaters. They have found it is important that the D-STAR repeaters be implemented to provide coverage as good if not better than the existing FM repeaters. I live 1 1/2 miles from a 57-story condo building that has 70cm 23 cm D-STAR digital voice repeaters and a 70cm D-STAR digital data repeater. The building also has a 440 FM repeater. I am also within HT coverage of several FM repeaters on 2m, 440 AND 1.2 GHz. That is the benefit of living in an urban area for me as a ham. The rural town I grew up in, Baraboo, WI, had one of the first wide-area 2m FM repeaters in Wisconsin at 1,200 feet above average terrain in the early 1970s. Within the next year that same site will have 2m, 70 cm 23cm D-STAR Digital Voice repeaters 23cm Digital Data repeaters that will cover a large rural area of south central Wisconsin in addition to an urban area like the state capitol of Madison, WI. The existing 2m 440 FM repeaters at this site which have excellent coverage will be retained. The reality is that most of American citizens live in urban areas. I don't believe we should let the constraints of a rural environment confine us to the least common denominator of technology. We need to continue to innovate use new technology as it becomes available feasible. Over time hams will adopt new technology as they understand its benefits and the new technology will be deployed in areas that have sufficient
Re: [digitalradio] Advantages of D-STAR Digital Voice Data
Mark, I think that you have more of a seller's interest in D-Star and I have a buyers interest. You spend a great deal of time promoting D-Star and wanting other hams to adopt this protocol and even doing presentations to a number of groups. Which is of course your prerogative and interest. But anyone who can tell me that the audio quality of D-Star is better than or even as good as FM is talking nonsense to me personally. That doesn't mean that the audio quality is not acceptable to many (maybe even most?) And it can hold the same quality for a longer time without going into the noise. That is not always a good thing as you have almost no warning when you drop out. I would rather have the warning and in some cases it can mean a significant ability to find the sweet spot again, such as with an HT. This is difficult to do with digital technology just like what happens with cell phones. What really did if for me was listening to the supposed claims of superior signals from D-Star vs.FM on the internet comparison. Others may differ. If you can convince the majority that this is good enough, or maybe even some with think it is better, then so be it. I am only describing my reaction to the quality. The speed of the data portion for the 2 meter/440 rigs is below late 1970's technology. It is disappointing. It has minimal usefulness due to the speed, but it has some usefulness in some situations as you point out. It is a difficult trade off to accept with modern technology. Compare that to cell phones with dial up speeds. I am skeptical about the distance of analog vs. digital voice with D-Star and would like to see many more comparisons on this since we have heard that it is less effective in distance and then you claim the opposite. There could be other reasons such as multipath? I am keeping an open mind on this, but am disappointed that there is not some clear technological superiority over FM when it comes to distance. Cost of equipment relative to the past is not relevant to current pricing. In general we have much lower priced equipment today with much improved performance. Everything has to be compared to today, not in the past. When FM came along very few people had it because in 1968 or thereabouts, it was mostly converted commercial equipment. The reason that FM eventually eclipsed AM is due to the technical superiority. It was cost effective, it had greater noise immunity, and the big one was that you could use it for repeaters. AM did not work well for this purpose. There was another technology that also was promoted for a while as the next great thing. ACSSB (Amplitude Compandered Single Side Band). It did not get big inroads into the commercial markets and it completely failed in the amateur markets. It should have allowed us SSB on repeaters if I understand it correctly since it had a pilot tone that insured the correct tuning (and better voice quality compared to off tuned SSB which we know is not easy to listen to or comprehend). If it proves out that D-Star has better range and hams like it, then it will should succeed, at least for a while, since it is a fairly open standard and really it is all we have right now and that is mainly due to one company putting a huge amount of resources into D-Star for a number of years now. You have to give ICOM credit for that. The other problem with digital is that the different digital system can not intercommunicate whether P-25, D-Star, MotoTRBO, etc. And its always possible another digital system may be coming along eventually. We have seen what has happened to digital modes on HF when you have low cost DSP type technology that allows new modes, sometimes in less than a year. Most of the new technologies that have come along in the past and required nearby participation for networking, are going to first have to come from the more populated areas. Rural areas typically need a catalyst, often one person, who is able to either pay for a system out of their own pocket or get enough other hams to want to do this. We saw this in the past in the nearby La Crosse area where at one time there were quite a few repeaters, some of which were well outside the immediate city area. But my rural area does not constrain you or anyone in metropolitan areas from doing what ever you wish to do. My viewpoint is what I see for our specific area. When I brought up D-Star at the last county level club meeting, there was just no interest at this time. No one else has ever even mentioned the word D-Star that I can recall. I have been the only ham who brings it up as a point of discussion so far. This will likely change, but you can not always be sure of that. I was one of three hams some years ago who tried to get TCP/IP and high speed 9600 baud packet at the user level. Never happened. Just not enough interest from the 150+ hams in that area, just north of where I now live. I question whether maintaining
