[DSTAR_DIGITAL] Re: APRS and D-Star
--- In dstar_digital@yahoogroups.com, n0uyx n0...@... wrote: why cant we send a MSG from one D-Star radio or user to the other? I was told here that can't be done. But if we can send HIGH speed I am going to approach this question from a different standpoint that might make more sense to the non-D-STAR community. APRS is designed around AX.25 but is not part of the AX.25 specification. In essence, APRS is a higher level protocol than AX.25. AX.25 is a transport protocol: it transports higher level protocols like APRS. D-STAR is a transport protocol: it transports higher level protocols like AMBE voice, Ethernet, serial data, etc. While AX.25 and D-STAR are very different (packet vs. streaming, etc.), we can use this analogy for this topic. There is no AX.25 - APRS messaging because there is no messaging in the AX.25 protocol. There is APRS - Winlink and APRS - email servers because those are servers connecting protocols that have messaging. There have even been some APRS - BBS type servers but those have been very limited due to the uniqueness of the various BBS protocols and the lack of BBS use anymore in many parts of the world. OK, so we can agree that there is no AX.25 - APRS messaging because AX.25 is soley a transport protocol that does not have messaging as part of the spec. You can use it to transport higher level protocols that do have messaging but AX.25 itself does not have messaging built- in. Now replace all references to AX.25 in this paragraph with D- STAR. While an over-simplification, this analogy gets to the heart of your question and the explanation of my response. 73, Pete AE5PL
[DSTAR_DIGITAL] Re: APRS and D-Star
On two meters and 440, we have programs in use called D-Chat and D-Rats that send data back and forth between users, either simplex or through a repeater connected to the gateway. There is no high speed data capability on two meters and 440 because high speed requires more bandwidth than we have available on those bands. D-Chat has been used in emergency tests and drills and can provide hard copy to back up voice communications. The ID-1 (1200 mHz D-Star radio)) is capable of 128k as there is bandwidth available on 1.2 gHz for the speed. Increased bandwidth means less range and to this point switching times have prevented using the ID-1 with amplifiers in the DD (digital data) mode, so range may be limited. It would require about 200 watts on DD to equal a ten watt DV signal. The ID-1 is capable of connecting to the internet for email and web surfing, although that is limited by regulations and would not be what you might consider high speed in computer world terms. D-Star radios can all forward D-PRS data to the D-PRS server which is posted to the net on sites like www.findu.com . Some radios can be purchased with optional GPS, and all can be connected with outboard GPS. So if I understand your questions, yes D-Star can allow text messages between stations, exchange of short files, and GPS tracking of units in the field while still allowing for voice communications-- all using the slow speed data capability available on 2 meters and 440. Ernie W6KAP --- In dstar_digital@yahoogroups.com, n0uyx n0...@... wrote: Let me run this by you guys once more. From what I am told D-Star is currently being used for Simulated Emergency Test and are sending DATA about patients at Hospitals. I get this info from a Guy who went to the Jacksonville, MS Hamfest and this info was put out at a D-Star conferense. OK so we take a PC and hook it up to a D-Star radio and can run HIGH Speed DATA with it right? OK so this being the case then why cant we send a MSG from one D-Star radio or user to the other? I was told here that can't be done. But if we can send HIGH speed data then of course it can be done if it's not being done right now is only maybe because somebody hasn't designed the software for it? Is this right? So if we can send HIGH speed data which could include MSG and Station Status or Beacon data and it makes it to the Internet then D-Star could send email, TEXT MSG and so on. Also a Server could be designed to handle D-Star/ APRS MSG so the two could send info or data from one to the other at a very limited size because of APRS data limits. Did I not ask this same thing a few weeks ago? Why couldn't the above be done? Lack of interest? D-Star Copyright Infringement? What am I missing here? DE WW5RM Randall
RE: [DSTAR_DIGITAL] Re: APRS and D-Star
Randall, I have to side with Pete on exactly what Pete just sent here. Look at it this way, can you send SMS via your mobile radio RIGHT NOW? Yes, then you have an aprs adapted Kenwood. I am not going to go any further because your locked in on that radio's features. Nothing we say will change that. If you say NO, then your locked in on a computer program that works with APRS. (WinAPRS, UI-View, or the others) YES, THAT IS SOFTWARE that does the messaging. NO it does not include D-Star. The MSG feature and Status feature is that of a Motorola hand-held that can be programmed to send MDC1200 MSG STAT. Again, that is not D-Star. You asked why could it not be done?, for one thing internal memory, that's why it is not in any of the D-Star radio's. You asked, is it because of lack of interest? I am going to say no. I am not into rewriting the Flash ROM on my 2820 to spin the dial for 20 mins just to send the message WHERE ARE YOU? I would sale my radio before I even think about spend any amount of time turning a knob to transmit a 20 letter message just to find out what your doing... I will pick up the mic and call you, you don't answer OH WELL. D-Star Copyright? Not sure why you ask this, the JARL published the coding for D-star. Evans --- In dstar_digital@yahoogroups.com mailto:dstar_digital%40yahoogroups.com , n0uyx n0...@... wrote: why cant we send a MSG from one D-Star radio or user to the other? I was told here that can't be done. But if we can send HIGH speed OK, so we can agree that there is no AX.25 - APRS messaging because AX.25 is soley a transport protocol that does not have messaging as part of the spec. You can use it to transport higher level protocols that do have messaging but AX.25 itself does not have messaging built- in. Now replace all references to AX.25 in this paragraph with D- STAR. While an over-simplification, this analogy gets to the heart of your question and the explanation of my response. 73, Pete AE5PL -- No virus found in this outgoing message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.18/1936 - Release Date: 2/5/2009 11:34 AM
