Questions tagged [aprs]

Automatic Packet Reporting System is a digital protocol used to transmit GPS position reports, telemetry, weather reports and text messages between APRS compatible devices and software.

The APRS system consists of the following components:

  • Trackers, small microcontroller-based devices which, when connected to a GPS receiver and a transmitter, transmit their location regularly over radio. Some trackers feature integrated GPS and radio modules. Trackers are available as kits, ready-made, and they're also relatively easy to build from parts.
  • Radio transceivers implementing the APRS protocol, such as Kenwood and Yaesu commercial offerings, which can act as trackers and normal voice radios at the same time, and implement text messaging and other APRS features
  • APRS applications for computers and mobile devices, typically having a tactical real-time map view of APRS stations
  • APRS web database sites, which provide real-time map views and historical APRS data lookup functions
  • APRS-IS, the APRS Internet System is a network of servers connecting radio-based APRS networks together over the Internet
  • The protocol itself, defining how the pieces of the system communicate

Questions concerning the APRS system or any of its components should have the aprs tag.

76 questions
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Is it possible to overload APRS?

Does APRS have a limited capacity in terms of beacons? What happens when an APRS frequency experiences a large number of packets?
JC Hulce
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Help understanding path taken by APRS packet

I'm looking at some raw APRS packets over APRS-IS. I'd like to determine which stations heard particular packets, but I'm having trouble understanding how TNC-2 paths work. Here are two examples: 2016-05-19 05:51:46 PDT:…
watkipet
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What's the difference between an APRS "item" and an APRS "object"?

What's the difference between an APRS "item" and an APRS "object"? A kenwood manual says Objects have timestamps, items do not. What does that mean, and how should it be used? Also in general: What is a good resource for learning about APRS?…
Thomas
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Decoding weak APRS signals

I've recently started looking into APRS, and can easily receive some APRS signals from my station - however, I can't seem to decode them using QTMM or any similar software. Is this because they're too weak / noisy, or am I doing something else…
berry120
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Help understanding the information field in an APRS-IS message

I'm looking at the raw packet data from http://aprs.fi. I see packets such as these: ROSLDG>APN390,HEBOWX,OR2*,qAR,MKSRDG:@015805z4501.34NF12351.41W_000/000g000t053r000p000P000h92b......U2k W7KKE-9>TTRSUT,NEWPRT*,OR2-1,qAR,W7GC-3:'4].…
watkipet
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What does the APRS 'to'/destination address mean?

I'm looking at incoming packets. Here's the beginning of a few messages: KF7WXW-9>TU3RTW,WIDE1-1,WIDE2-1:`2D<.. KX5ONE-9>T5SRPV,WIDE1-1,WIDE2-1:`2E0.. KX5ONE-9>T5SRSV,WIDE1-1,WIDE2-1:`2E .. So, what to the Txxxxx labels mean? The APRS spec talks…
300D7309EF17
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String in APRS report

Here are two messages I received: 10:50:53R W2MEB-9>SX2X9U,W0BJ-1*,K0ATT-10*,WIDE2* :`vNN" dk/]"64}Monitoring 144.905= 10:50:58R WB9QPM-4>APBPQ1,AD9OV-8*,WIDE2* :!3924.30N/08848.72WI Shelbyville Igate EM59oj What I'm…
Duston
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Getting Started with APRS

The APRS.org web site provides some good information but is not very well organized and does not appear to be actively maintained. What are some good resources for beginners seeking the following: Minimum equipment needed to receive packets Minimum…
user157
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Transferring Images From Picoballoon SSDV over APRS/RTTY or raw packet/other modes

I've recently become extremely interested in tiny "picoballoons" which can float around the world multiple times in some cases. I was extremely surprised to find DL7AD's picoballoon, which has a camera and can transmit images with SSDV over APRS.…
Vera Fodor
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Fetching data from APRS-IS.net

I would like to fetch the data transmitted by a specific radio station from APRS-IS.net servers. I've read the documentation on their site and it is not clear how you would do it, if you are fetching the data instead of transmitting it. It is…
Daniela
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APRS: What's the `n` in WIDEn-N?

In every description I've found of WIDEn-N, the capital N is described as the "hop count" / "ttl" (comparable to internet packets). But the lower case n I've never found defined. Looks like "higher number means wider reach", but what does that mean…
Thomas
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In HLDC framing/Bell202 encoding, are the flag bytes NZRI encoded?

I have previously implemented an APRS transmitter from scratch by manually generating the modulated sine wave. In this implementation, I did NZRI encoding over the entire packet (including postamble and preamble), though only the payload bytes were…
chris12892
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What is 1700 in SoundModem by UZ7HO?

As a red circle in the picture, What does 1700 number means? When I change it to another value seems like it can not decode APRS sound. So what is it(1700 in textbox after ChA label)?
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Feeding APRS data into GR Level 3

Our Skywarn group is looking for a way to feed the positions of our spotters (reported via APRS) to into GRLevel3 to be displayed on the map. Does anyone know of a tool for doing this, or documentation that might help us create our own data feed?
Brad Mace
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#APRS error ? (only visible on aprsc status)

I'm playing with Nodered that I'm trying to use to place an aprs object: it works but it does not suit me! No error on findu.com, correct display of frames on aprs.fi or on aprsdirect.com ... but on the other hand aprsr-is server is reporting a…
Phil
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