Automatic Packet Reporting System (APRS)

 APRS, or the Automatic Packet Reporting System, developed by Bob Bruninga, WB4APR, in the early 1980s, is a digital communication protocol used in amateur radio for real-time exchange of information such as location, weather reports, text messages, and telemetry data. It operates on VHF and UHF frequency bands using packet radio technology in AX.25 format at 1200 baud, transmitting unconnected packets that are repeated locally by digipeaters and can be ingested into the APRS Internet System (APRS-IS) for global access.

APRS is not merely a vehicle tracking system but a two-way, real-time tactical communications system that enables all network participants to share information about their immediate surroundings, including station status, weather conditions, emergency alerts, and more. The system integrates mapping technology to display data like moving objects, fixed stations, weather stations, and search and rescue information on a shared live map, making it invaluable for emergency response, special events, and general ham radio coordination.

The primary frequency for Automatic Packet Reporting System (APRS) in North America is 144.390 MHz, which serves as the national APRS frequency for real-time data communications. In addition, there are two alternate frequencies used in the Puget Sound region: 144.35 MHz and 440.800 MHz, both operating at 9600 baud AFSK. The 440.800 MHz frequency is specifically noted as an alternate for the Puget Sound area. https://www.nwaprs.info/

APRS beacon and location is posted to the APRS.FI https://aprs.fi/ and APRS.TO https://aprs.to/ webpages.

APRS THURSDAY APRS Thursday is a net managed by Michael KC8OWL, held every Thursday from 00:00 UTC to 23:59 UTC. The purpose of this event is to grow message activity on APRS (Automatic Packet Reporting System) across the world. Participants send messages to the net (ANSRVR) using the format CQ [space] HOTG [space] Your message, where "HOTG" is a group that includes all callsigns currently joined to the net. This event aims to promote and enhance the use of APRS among amateur radio operators.

APRSPH https://aprsph.net/aprsthursday/ runs a similar net and also logs APRS THURSDAY check-ins.

ANSRVR - To create a group on ANSRVR, send an APRS message to the ANSRVR server with the command CQ groupname text, where groupname is the desired name for your group and text is the initial message or description you want to send to the group. If the group does not already exist, this command will create it and designate you as the owner. The message body must start with CQ followed by the group name and the text, separated by spaces. This action both joins you to the group and sends your message to all current members. The group will remain active as long as you continue to send messages or use the K command to keep it active.

To join a group, send to ANSRVR the command J GROUP. To send a message to all group members send to ANSRVR the command CQ GROUP your message. To leave the group send to ANSRVR the command U GROUP


Michael Phelps NA7Q has set up an APRS SMS server and an APRS Mail server. 

SMS - All SMS users are required to opt-in due to carrier regulations used by this service. By opting in at https://aprs.wiki/ you agree to receive SMS messages from APRS or Winlink users of this service.

MAIL -     To send a message directly to another APRS user, type: @CALLSIGN followed by your message. To check your incoming messages send APRSM to the Mail server.


Other APRS queries include:

WhatsApp https://wtsapp.org/ 
WTSAPP
@+123-456-7890 this is my message
The first letter is an @ sign which will indicate a command to send messages: It should be followed by an international phone number or an alias. The phone number MUST BE in international format, otherwise it won’t work. This means it MUST START with the country code.


WXBOT will return weather for your last beaconed location.

    Optionally, you can specify "where" "when" and "what"
  
The "where" can take the following form:    
Any US callsign
City,ST (Use US postal service abbreviations for states.)
5 digit zipcode
lat/lon  Using decimal degrees I.E. 41.123/-122.1123
4 character ICAO station  or 3 character IATA station returns METAR report.

The "When" can be a day of the week, with an optional "night" to indicate the evening forecast.
today   -- (default)
tonight
tomorrow [night]
Monday [night]
Tuesday [night]... etc.

The "What" can be:
brief -- default.  Short forecast. Usually a single APRS Message.
full  -- multi line more complete forecast.
current -- Returns current conditions from the nearest NWS station.
metar -- Returns the current conditions from the specified. ICAO station in METAR form. If an ICAO station is not specified, the nearest ICAO station to the given location is used.
cwop -- Returns weather report from the CWOP station nearest to the given location. If no location was given, it assumes your location. If a callsign was given, it returns results from the CWOP station nearest to the location of the callsign.

 

WXCAN  accesses Environment Canada's weather data, based on city name

Send: Montreal - WXCAN responds: Montreal: Cond: Partly Cloudy, Temp: 18C, Wind: 15 km/h, Dir: NW

Send: Montreal full - WXCAN responds: Montreal: Cond: Partly Cloudy, Temp: 18C, Wind: 15 km/h, Dir: NW, WindChill: 16C, Vis: 24 km, Press: 101.2 kPa, Hum: 65%, Normals: Low 8C. High 20C

Send: Montreal tomorrow - WXCAN responds: Montreal: Tomorrow: Cond: Mainly Sunny, Temp: 22C, Wind: 20 km/h, Dir: SW

Send: Vancouver tonight (or Vancouver tn for short) - WXCAN responds: Vancouver: Tonight: Cond: Increasing Cloudiness, Temp: 12C, Wind: 5 km/h, Dir: SE


EMAIL - The easiest way to send email is to send a message to EMAIL with the recipient's email address as the first "word" of the message. You may only send one line messages (67 total characters maximum). Currently, EMAIL and EMAIL-2 are the callsigns for the general email servers.

For bidirectional communication, the EMAIL-2 server allows recipients to reply via email, but the reply must follow a specific format: the email subject must start with the sender’s callsign and SSID (in uppercase), followed by a colon and the message text, while the email body must contain userid:shortcut: where shortcut is the predefined alias associated with the sender’s email address. This system helps prevent spam and ensures only authorized users can send messages to a ham radio operator’s station.

In all cases, users must ensure they are within range of an APRS digipeater or gateway that supports two-way communication, as one-way gateways cannot handle replies.

APRSLink https://winlink.org/APRSLink is a CMS-Hosted gateway providing a link between the Automatic Packet Reporting System (APRS) and the Winlink global radio email system. APRSLink monitors all APRS traffic gated to the internet, worldwide, and watches for special commands that allow APRS users to connect to Winlink Global Radio Email.

NTSGTE https://nts2.arrl.org/ntsgte-an-aprs-nts-gateway/ is an APRS information service that receives radiograms and forwards them on to the Digital Traffic Network.  Radiograms are then relayed on as usual.  This service can be useful in situations where you need to send a radiogram but are unable to check in to a traditional NTS net.


FIND callsign - returns the last known position and status of the requested callsign within the APRS network.


WHO-IS f callsign - returns name and address associated with the callsign.

WHERE-IS callsign - returns distance, bearing to, and time of latest beacon of the listed callsign. 


The Multi-Purpose APRS Daemon (MPAD) allows for additional queries. 

Send the following queries to MPAD

WHEREAMI - returns your last beaconed location

OSM item - returns the location of the designated item from Open Street Maps. For example, OSM Supermarket would return the location of the nearest supermarket to your location. Use the Top3 command to get the three closest items, OSM Supermarket Top3 will return the three closest supermarkets to your location. Additional OSM queries include:

aerodrome [Airport]
bank
chemist [Pharmacy]
fire_station
fuel
hospital
motel
police
post_office

POSMSG email@address.com - sends your location (last beaconed position) to the email address specified. 

REPEATER returns the closest repeater. Use specifications to locate by capability: repeater 70cm returns the nearest 70cm repeater, repeater c4fm returns the nearest system fusion repeater, etc. Use top3 to return three closest repeaters.

RISESET returns the time of sunrise and sunset for your location (last beaconed position).

APRS Graffiti Wall https://radiorabbit.ca/aprs-wall/ 

Send a message to GWALL via APRS using the following format: P <your message here>

GWALL Commands:

• P[OST] <msg>- Post a message to the wall.
• D[EL] - Delete your latest post.
• R[AND] - Fetch a random Graffiti Wall post.
• L[ATEST] - Fetch the lastest post.
• A[BOUT] - About Graffiti Wall.
• H[ELP] or ? - Help (this message).

APRS DROID https://aprsdroid.org/ is an Android application for Amateur Radio operators. It allows reporting your position to the APRS (Automatic Packet Reporting System) network, displaying of nearby amateur radio stations and the exchange of APRS messages. Once connected, you can beacon your presence, see which stations (amateurs and repeaters) are around and send/receive APRS messages. iPhone users can install the APRS.FI APP https://ios-guide.aprs.fi/

 

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References:

APRS Foundation https://how.aprs.works/ 
MPAD https://github.com/joergschultzelutter/mpad
MPAD Queries https://github.com/joergschultzelutter/mpad/blob/master/docs/COMMANDS/ACTION_KEYWORDS.md