Author Topic: APRS- What's all the buzz about???  (Read 2099 times)

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Offline AJ4YS

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APRS- What's all the buzz about???
« on: May 07, 2013, 08:55:52 AM »
I'll start this off...by asking Randy (W4WRB) to initiate conversation with his thoughts and comments regarding APRS, what it is, what it can be, what can we do with it as a club or group, and how can we better serve our community with it......

Randy..Let the "fireside chat" begin....

Offline AJ4YS

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Re: APRS- What's all the buzz about???
« Reply #1 on: May 09, 2013, 12:01:49 PM »
OK, Guess I'll start off then...excerpts on the WHAT part of APRS......

Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time tactical digital communications of information of immediate value in the local area. In addition, all such data is ingested into the APRS Internet System (APRS-IS) and distributed globally for ubiquitous and immediate access. Along with messages, alerts, announcements and bulletins, the most visible aspect of APRS is its map display. Anyone may place any object or information on his or her map, and it is distributed to all maps of all users in the local RF network or monitoring the area via the Internet. Any station, radio or object that has an attached GPS is automatically tracked. Other prominent map features are weather stations, alerts and objects and other map-related amateur radio volunteer activities including Search and Rescue and signal direction finding.

Network overviewAPRS (Automatic Packet Reporting System), is a digital communications protocol for exchanging information among a large number of stations covering a large (local) area, often referred to as "ey-pers". As a multi-user data network, it is quite different from conventional packet radio. Rather than using connected data streams where stations connect to each other and packets are acknowledged and retransmitted if lost, APRS operates entirely in an unconnected broadcast fashion, using unnumbered AX.25 frames.[2] APRS packets are transmitted for all other stations to hear and use. Packet repeaters, called digipeaters, form the backbone of the APRS system, and use store and forward technology to retransmit packets. All stations operate on the same radio channel, and packets move through the network from digipeater to digipeater, propagating outward from their point of origin. All stations within radio range of each digipeater receive the packet. At each digipeater, the packet path is changed. The packet will only be repeated through a certain number of digipeaters -or hops- depending upon the all important "PATH" setting. Digipeaters keep track of the packets they forward for a period of time, thus preventing duplicate packets from being retransmitted. This keeps packets from circulating in endless loops inside the ad-hoc network. Eventually most packets are heard by an APRS Internet Gateway, called an IGate, and the packets are routed on to the Internet APRS backbone (where duplicate packets heard by other IGates are discarded) for display or analysis by other users connected to an APRS-IS server, or on a website designed for the purpose. While it would seem that using unconnected and unnumbered packets without acknowledgment and retransmission on a shared and sometimes congested channel would result in poor reliability due to a packet being lost, this is not the case due to the fact that the packets are transmitted (broadcast) to everyone, and multiplied many times over by each digipeater. This means that all digipeaters and stations in range get a copy, and then proceed to broadcast it to all other digipeaters and stations within their range. The end result is that packets are multiplied more than they are lost. Therefore, packets can sometimes be heard some distance from the originating station. Packets can be digipeated tens of kilometers or even hundreds of kilometers depending on the height and range of the digipeaters in the area.

When a packet is transmitted, it is duplicated many times as it radiates out, taking all available paths simultaneously, until the number of "hops" allowed by the path setting is consumed.


In its simplest implementation, APRS is used to transmit real-time data, information and reports of the exact location of a person or object via a data signal sent over amateur radio frequencies. In addition to real-time position reporting capabilities using attached Global Positioning System receivers, APRS is also capable of transmitting a wide variety of data, including weather reports, short text messages, radio direction finding bearings, telemetry data, short e-mail messages (send only) and storm forecasts. Once transmitted, these reports can be combined with a computer and mapping software to show the transmitted data superimposed with great precision upon a map display.

While the map plotting is the most visible feature of APRS, the text messaging capabilities and local information distribution capabilities combined with the robust network should not be overlooked; the New Jersey Office of Emergency Management has an extensive network of APRS stations to allow text messaging between all of the county Emergency Operating Centers in the event of the failure of conventional communications.





« Last Edit: May 10, 2013, 07:05:01 AM by AJ4YS »

Offline KK4BBG

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Re: APRS- What's all the buzz about???
« Reply #2 on: May 10, 2013, 09:53:38 AM »
what can we do with it as a club or group, and how can we better serve our community with it? 

As an "Emergency Communications" based organization we can provide for  our served agency by providing them with manpower and equipment  as needed for search and rescue, large scale incidents, MCI, assesment of damages after large scale events and any other times when locating, or marking an area when requested is needed. 

By going out to a designated area with the right equipment and operator can go "mark" an exact location by setting it as a Beacon point on APRS so agencies can know what  resources are needed. It can also be used to "trace" how much of an area has been searched.


We can serve our community better  by  being more "Aprs friendly" to other organizations that use our area for large scale events, be it a multi county bike ride to the extremes of a multi county natural disaster where more than one organization could be in need of assisitng our or other  organizations.



APRS is still relatively knew. its not all about  postion reporting.  As we have discussed before you can send "somewhat secure" message over the same frequency as the packet for positioning is  sent over and small scale reports could be sent over that data.







Always listening...

BCARS, MTARS, and SMRC member

Offline AJ4YS

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Re: APRS- What's all the buzz about???
« Reply #3 on: May 10, 2013, 01:16:44 PM »
Check this link

http://mountainrescue.us/aprs/qst_article.pdf

Prime example of the usage of APRS for the community....we may not have mountains, but we have rivers, wooded areas, and some rough terrain as well.

Offline KI4RQK

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Re: APRS- What's all the buzz about???
« Reply #4 on: May 11, 2013, 10:57:43 AM »
Heavy reading, This is the technical specs for the APRS system and message formats.. not sure anybody will find any use in it but thought I would post it in case anybody was interested..


Working on putting together some info on messaging and directing MSG's to specific users and/or groups of users..

Offline KI4RQK

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Re: APRS- What's all the buzz about???
« Reply #5 on: May 11, 2013, 10:58:44 AM »
Beginners Guide to information about APRS.. what is it? why should we use it? What is it able to do?

Offline AJ4YS

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Re: APRS- What's all the buzz about???
« Reply #6 on: May 14, 2013, 07:50:45 AM »
Well this is certainly going everywhere at the speed of sound, eh???

Offline KI4RQK

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Re: APRS- What's all the buzz about???
« Reply #7 on: May 14, 2013, 08:02:49 AM »
Yes.. a very lively, active participation, is it not?

Got the cable for my radio.. Hoping to get the GPS unit today.. I can keep using my current antenna til the new one arrives, but if i get the GPS today I can get started on playing with it and getting familiar with the operation of it ..

Since i am running DroidAPRS on my phone i can even practice sending messages/bulletins/etc i hope ..

Offline KK4BBG

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Re: APRS- What's all the buzz about???
« Reply #8 on: May 02, 2014, 12:29:03 PM »
As I have been playing with my new little unit I traded a baofeng radio and some accessories for, I have found out that its not just Bedford county that is slacking. ALOT of Rutherford is also dark. Ashley and I were driving around different areas and I got "lost" after leaving the movie theater. When I got back to an internet source to check my route only 4 miles of my route were tracked on lascassas pike, and I d rove around a whole bunch of areas.

I really would like to see an IGATE at the EMA and some digipeaters spread about. Since I'm working a lot of overtime there may be a digipeater on my "hill" within the next few weeks.


Out of all the HAMS that are at the Tn Fire Codes Academy this weekend for the AUXCOMM exercise only one of them is making it to Columbia's igate.

http://aprs.fi/#!mt=roadmap&z=11&call=a%2FW4PHS&timerange=3600&tail=3600
Always listening...

BCARS, MTARS, and SMRC member

 

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