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AL7OC -> RE: D-Star vs P25 (4/22/2006 2:58:02 PM)
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When the term "illegal" is mentioned, I assume we are talking about technology or software licensing problems. There shouldn't be any technical problems for using P25 under 47CFR Part 97 so long as you aren't using encryption.
There are some P25 amateur repeaters and stations around. The Motorola Amateur Radio Club MARC (K5MOT) has a P25 amateur system on the air somewhere in Texas and there are a few others as well. I'll bet that the clubs have access to P25 prototypes or some surplus equipment. Maybe some forum readers could get some folks from MARC to talk about P25 as well? Can we get some D-STAR and MARC hams to do some side-by-side comparisons and report the results to our community? The idea is not to knock either protocol, but to lay out the technical pros and cons for each. From there, we could also include cost comparisons and get the bigger picture.
It sounds like the problem getting amateur manufacturers to make P25 gear is the licensing issues with Motorola. If Motorola were to grant P25 licenses to manufacture amateur equipment with P25 technology, then there is probably no leagal reason why we couldn't adopt the standard. The hitch is going to be how much do you want to pay for the technology? As I stated before, current P25 equipment for the VHF ALMR system is very expensive - portables and mobiles run around $3000 each. That is why our SAR team has not made any P25 purchases yet.
I am not an expert on all of the characterisitcs of P25, but from what I have read, I see no major technical benefits of using P25 over D-STAR. The AMBE vocoder used in D-STAR appears to be more versatile than the IMBE vocoder used in P25. P25 systems tend to be trunked systems which are not commonly used in amateur service, so that part of P25 technology doesn't bring us much value for the cost.
It appears to me that the D-STAR concept is really designed to better address the communications needs of the amateur service. The technology is new and maybe not as mature as P25, but that gives us an "in" at the ground level to develop software applications suited to ARES/RACES applications. D-STAR is mainly a digital transport protocol and the advantages lie in whatever applications you create to best utilize it.
Now is the time for EMCOMM specialists to sit down with amateurs with software talents and come up with applications that best suit our needs. D-STAR is in its infancy, and there are so many opportunities to create a very powerful amateur communication tool. I strongly urge EMCOMM specialists to work together to specify and develop software applications. My first suggestion is an application for laptops and PDAs which would be similar to a computer aided dispatch program used in public safety communications. Such a program would automatically track and log the location and status of mobile field units at an event, freeing the "dispatcher" or SYSOP to focus more on important emergency messages. You could add canned HTML report forms where field units "fill in the blanks" with information and have the field data populate the report form at the dispatch location. The forms could be printed out and passed on to officials.
D-STAR would certainly support such types of communications applications, plus it also supports connecting remote locations over TCP-IP.
Anyway, I have probably rambled enough. I have experience as a volunteer EMS dispatcher, firefighter, and K9 SAR handler, so I have a lot of exposure to public safety communications. Based on my experience, there is a whole lot of good that you can do with D-STAR to support EMCOMM if you work on developing your applications.
Regards,
Pierre
AL7OC
Fairbanks, Alaska
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