The DMR Tech Net team discuss APRS (Automatic Packet Reporting System), Part Two

Posted on August 5, 2024

Automatic Packet Reporting System

From Wikipedia, the free encyclopedia

APRS beacon transmitter with GPS receiver.

Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area.[1] Data can include object Global Positioning System (GPS) coordinates Non-directional beacon, weather station telemetry, text messages, announcements, queries, and other telemetry. APRS data can be displayed on a map, which can show stations, objects, tracks of moving objects, weather stations, search and rescue data, and direction finding data.

APRS data is typically transmitted on a single shared frequency (depending on country) to be repeated locally by area relay stations (digipeaters) for widespread local consumption. In addition, all such data are typically ingested into the APRS Internet System (APRS-IS) via an Internet-connected receiver (IGate) and distributed globally for ubiquitous and immediate access.[2] Data shared via radio or Internet are collected by all users and can be combined with external map data to build a shared live view.

APRS was developed from the late 1980s forward by Bob Bruninga, call sign WB4APR, a senior research engineer at the United States Naval Academy. He maintained the main APRS Web site until his death in 2022.[3][4] The initialism “APRS” was derived from his call sign.

History

Bob Bruninga, a senior research engineer at the United States Naval Academy, implemented the earliest ancestor of APRS on an Apple II computer in 1982.[5] This early version was used to map high frequency Navy position reports. The first use of APRS was in 1984, when Bruninga developed a more advanced version on a VIC-20 for reporting the position and status of horses in a 100-mile (160 km) endurance run.[6]

During the next two years, Bruninga continued to develop the system, which he then called the Connectionless Emergency Traffic System (CETS). Following a series of Federal Emergency Management Agency (FEMA) exercises using CETS, the system was ported to the IBM Personal Computer. During the early 1990s, CETS (then known as the Automatic Position Reporting System) continued to evolve into its current form.

As GPS technology became more widely available, “Position” was replaced with “Packet” to better describe the more generic capabilities of the system and to emphasize its uses beyond mere position reporting.

Bruninga has also stated that APRS was not meant to be a vehicle position tracking system, and can be interpreted rather as “Automatic Presence Reporting System”.[7]

Network overview

APRS (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 “IP-ers”. 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.[8]

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 be repeated through only 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 Web site 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, because 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 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 digitally repeated 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.

Positions/objects/items

Screenshot of an APRS display in XASTIR, an APRS software system for Linux/Unix. Station positions, objects and items are displayed on a map overlaying counties around New York City. Raw APRS messages are displayed in the terminal window on the lower right.

APRS contains a number of packet types, including position/object/item, status, messages, queries, weather reports and telemetry. The position/object/item packets contain the latitude and longitude, and a symbol to be displayed on the map, and have many optional fields for altitude, course, speed, radiated power, antenna height above average terrain, antenna gain, and voice operating frequency. Positions of fixed stations are configured in the APRS software. Moving stations (portable or mobile) automatically derive their position information from a GPS receiver connected to the APRS equipment.[8]

The map display uses these fields to plot communication range of all participants and facilitate the ability to contact users during both routine and emergency situations. Each position/object/item packet can use any of several hundred different symbols. Position/objects/items can also contain weather information or can be any number of dozens of standardised weather symbols. Each symbol on an APRS map can display many attributes, discriminated either by colour or other technique. These attributes are:

  • Moving or fixed
  • Dead-reckoned or old
  • Message capable or not
  • Station, object or item
  • Own object or other station object/item
  • Emergency, priority, or special

Status/messages

The Status packet is free-field format that lets each station announce its current mission or application or contact information or any other information or data of immediate use to surrounding activities. The message packet can be used for point-to-point messages, bulletins, announcements or even email. Bulletins and Announcements are treated specially and displayed on a single “community Bulletin board”. This community bulletin board is fixed size and all bulletins from all posters are sorted onto this display. The intent of this display is to be consistent and identical for all viewers so that all participants are seeing the same information at the same time. Since lines are sorted onto the display, then individual posters can edit, update, or delete individual lines of their bulletins at any time to keep the bulletin board up-to-date to all viewers.

All APRS messages are delivered live in real-time to online recipients. Messages are not stored and forwarded, but retried until timed out. The delivery of these messages is global, since the APRS-IS distributes all packets to all other IGates in the world and those that are messages will actually go back to RF via any IGate that is near the intended recipient.

Email

A special case message can be sent to EMAIL where these messages are pulled off the real-time APRS-IS and wrapped into a standard email message type, and forwarded into regular Internet email. This was done by the WU2Z email engine until 2019 , when it was replaced by the javAPRSSrvr email gateway.[9]

Capabilities

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 GPS 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.

Technical information

1200 baud APRS signal

Duration: 1 second.0:01

Example of a 1,200-baud AFSK modulated APRS signal.

Problems playing this file? See media help.

In its most widely used form, APRS is transported over the AX.25 protocol using 1,200-bit/s Bell 202 AFSK on frequencies located within the 2-meter amateur band.

Sample APRS VHF frequencies

An extensive digital repeater, or “digipeater” network provides transport for APRS packets on these frequencies. Internet gateway stations (IGates) connect the on-air APRS network to the APRS Internet System (APRS-IS), which serves as a worldwide, high-bandwidth backbone for APRS data. Stations can tap into this stream directly, and a number of databases connected to the APRS-IS allow Web-based access to the data as well as more advanced data-mining capabilities. A number of low-Earth orbiting satellites, including the International Space Station, are capable of relaying APRS data.

Equipment settings

An APRS infrastructure comprises a variety of Terminal Node Controller (TNC) equipment put in place by individual amateur radio operators. This includes sound cards interfacing a radio to a computer, simple TNCs, and “smart” TNCs. The “smart” TNCs are capable of determining what has already happened with the packet and can prevent redundant packet repeating within the network.

Reporting stations use a method of routing called a “path” to broadcast the information through a network. In a typical packet network, a station would use a path of known stations such as “via n8xxx,n8ary.” This causes the packet to be repeated through the two stations before it stops. In APRS, generic call signs are assigned to repeater stations to allow a more automatic operation.

Recommended path

Throughout North America (and in many other regions) the recommended path for mobiles or portable stations is now WIDE1-1,WIDE2-1.[15] Fixed Stations (homes, etc.) should not normally use a path routing if they do not need to be digitally repeated outside of their local area, otherwise a path of WIDE2-2 or less should be used as requirements dictate. The path parameter[clarification needed] reflects the routing of packets via the radio component of APRS, and fixed stations should carefully consider their choice of path routing. Any path selection for stations that do not require it contributes to congestion of the APRS frequency and may hinder other stations’ reporting. Aircraft and balloon APRS stations should avoid beaconing with any path at altitude since digipeating may not be necessary due to their antenna height and likelihood of reaching multiple wide-ranging digipeaters and IGates. Mobile stations in congested areas or more populated areas may consider using only 1 hop (WIDE1-1), as there are usually enough Internet gateways nearby that no path routing is needed. One solution to the path selection is proportional pathing[16] if the user’s equipment is capable.

Old path

Early on, the widely accepted method of configuring stations was to enable the short-range stations to repeat packets requesting a path of “RELAY” and long-range stations were configured to repeat both “RELAY” and “WIDE” packets. This was accomplished by setting the station’s MYALIAS setting to RELAY or WIDE as needed. This resulted in a path of RELAY,WIDE for reporting stations. However, there was no duplicate packet checking or alias substitution. This sometimes caused beacons to “ping pong” back and forth instead of propagating outwards from the source. This caused much interference. With no alias substitution, one could not tell which digipeaters a beacon had used.

New path

With the advent of the new “smart” TNCs, the stations that used to be “WIDE” became “WIDEn-N.” This means a packet with a path of WIDE2-2 would be repeated through the first station as WIDE2-2, but the path will be modified (decremented) to WIDE2-1 for the next station to repeat. The packet stops being repeated when the “-N” portion of the path reaches “-0.” This new protocol has caused the old RELAY and WIDE paths to become obsolete. Digi operators are being asked to re-configure fill-in “RELAY” stations to instead respond to WIDE1-1. This results in a new, more efficient path of WIDE1-1,WIDE2-1.

Amateur Radio High Altitude Balloons

Testing radio range is often a large component of these hobbies. Amateur radio is often used with packet radio to communicate with 1200 baud, using the Automatic Packet Reporting System back to the ground station. Smaller packages called micro or pico trackers are also built and run under smaller balloons. These smaller trackers have used Morse code, Field Hell, and RTTY to transmit their locations and other data[17]

Related systems

The APRS protocol has been adapted and extended to support projects not directly related to its original purpose. The most notable of these are the FireNet and PropNET projects.

  • APRS FireNet is an Internet-based system using the APRS protocol and much of the same client software to provide fire fighting, earthquake, and weather information in much higher volume and detail than the traditional APRS system is capable of carrying.
  • PropNET uses the APRS protocol over AX.25 and PSK31 to study radio frequency propagation. PropNET “probes” transmit position reports, along with information on transmitter power, elevation, and antenna gain, at various frequencies to allow monitoring stations to detect changes in propagation conditions.[18] It is based on ACDS, a special client program running under Microsoft Windows.

https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System

With APRS, what is an igate and what is a digipeater?

In APRS (Automatic Packet Reporting System), iGates and digipeaters are crucial components that help extend the reach and functionality of the network. Here’s an explanation of each:

iGate (Internet Gateway)

Purpose:

  • An iGate (Internet Gateway) acts as a bridge between the local RF (Radio Frequency) APRS network and the global APRS-IS (Internet System).

Functionality:

  1. Receive and Forward: iGates receive APRS packets transmitted by nearby stations (e.g., mobile units, weather stations) via radio frequencies.
  2. Internet Relay: The iGate forwards these packets to the APRS-IS network over the internet.
  3. Two-Way Communication: Some iGates also receive APRS packets from the APRS-IS network and transmit them via RF, although this functionality is less common.

Example Use Case:

  • When a mobile station sends out an APRS beacon, an iGate picks it up and forwards the data to the APRS-IS. This allows the beacon to be visible on global tracking websites like aprs.fi.

Diagram:

[ APRS Station ]  –>  [ iGate (RF Receiver) ]  –>  [ Internet ]  –>  [ APRS-IS Network ]

^                      |                             |                    |

|                      v                             v                    v

(APRS Packet)         (Packet Reception)           (Internet Relay)   (Global Data Access)

Digipeater (Digital Repeater)

Purpose:

  • A digipeater (Digital Repeater) extends the range of APRS transmissions by receiving and retransmitting APRS packets on the same frequency.

Functionality:

  1. Receive and Store: A digipeater receives an APRS packet transmitted by a station.
  2. Rebroadcast: It retransmits the packet after a brief delay, allowing the signal to cover a greater distance.
  3. Packet Management: Digipeaters typically add their callsign to the packet’s path history to avoid endless loops and prevent network congestion.

Example Use Case:

  • A mobile station sends an APRS beacon that cannot directly reach an iGate. A nearby digipeater picks up the beacon, retransmits it, and the repeated signal is then picked up by an iGate further away.

Diagram:

[ APRS Station ]  –>  [ Digipeater (Receive) ]  –>  [ Digipeater (Transmit) ]  –>  [ iGate / Other Stations ]

^                      |                                |                              |

|                      v                                v                              v

(APRS Packet)       (Packet Reception)                (Packet Rebroadcast)           (Extended Coverage)

Key Differences:

  • iGate:
    • Purpose: Connects local RF APRS traffic to the global internet-based APRS-IS network.
    • Function: Receives local APRS packets and forwards them to the internet, sometimes also rebroadcasting internet packets locally.
    • Usage: Essential for making APRS data available online for global tracking and access.
  • Digipeater:
    • Purpose: Extends the RF range of APRS packets within the local area.
    • Function: Receives and retransmits APRS packets to cover greater distances.
    • Usage: Critical for maintaining APRS network coverage in areas with limited direct line-of-sight communication.

Both iGates and digipeaters are vital for maintaining robust APRS network functionality, allowing for effective tracking, messaging, and data sharing across wide areas.

APRS on Analog Amateur Radio

APRS (Automatic Packet Reporting System) can be used with both analog and digital amateur radio systems, each having distinct characteristics and advantages. Here’s a comparison between APRS on analog and digital amateur radio:

Key Characteristics:

  1. Frequency and Modulation:
    • Uses traditional VHF/UHF frequencies.
    • Typically employs AFSK (Audio Frequency Shift Keying) modulation for transmitting APRS data.
    • Common frequency: 144.390 MHz (in North America).
  2. Hardware:
    • Requires a TNC (Terminal Node Controller) or a sound card interface to decode the AFSK signals.
    • Many modern transceivers have built-in APRS functionality.
  3. Network Infrastructure:
    • Relies on digipeaters to extend the range of APRS packets.
    • Simplex communication (direct radio-to-radio).
  4. Data Throughput:
    • Limited by the bandwidth and modulation method, typically 1200 baud.
  5. Compatibility:
    • Widely supported across a broad range of radios and devices.
    • Compatible with the vast majority of existing APRS infrastructure.
  6. Usage:
    • Commonly used for local tracking, messaging, and telemetry.
    • Ideal for areas with established analog APRS infrastructure.

Advantages:

  • Simplicity: Easier to set up and use with widely available equipment.
  • Wide Adoption: Well-established infrastructure and support.
  • Interoperability: Compatible with a broad range of devices and systems.

Disadvantages:

  • Lower Data Rate: Limited bandwidth for data transmission.
  • Potential for Congestion: Analog channels can become crowded in high-use areas.

APRS on Digital Amateur Radio (DMR, D-STAR, System Fusion)

Key Characteristics:

  1. Frequency and Modulation:
    • Uses the same VHF/UHF frequencies but with digital modulation schemes (e.g., GMSK for D-STAR, C4FM for System Fusion, TDMA for DMR).
    • Digital voice channels can carry APRS data.
  2. Hardware:
    • Digital radios with built-in GPS and APRS functionality (e.g., Anytone 878 for DMR, Icom IC-705 for D-STAR, Yaesu FT-3DR for System Fusion).
    • Often integrates with networked repeaters and digital gateways.
  3. Network Infrastructure:
    • Utilizes digital repeaters and internet gateways to extend the range.
    • Can send APRS data over the internet using systems like DMR’s BrandMeister network.
  4. Data Throughput:
    • Higher data rates than analog, allowing for more robust data transmission.
    • Typically more efficient use of spectrum with time-slot and code-division multiplexing.
  5. Compatibility:
    • Requires compatible digital radios and infrastructure.
    • Digital-specific networks and talk groups.
  6. Usage:
    • Effective for long-distance tracking and data transmission.
    • Useful in areas with good digital network coverage and internet connectivity.

Advantages:

  • Higher Data Rate: More efficient data transmission with higher bandwidth.
  • Network Integration: Seamless integration with digital repeater networks and internet gateways.
  • Clearer Signals: Improved signal quality and reliability.

Disadvantages:

  • Complexity: More complex setup and configuration.
  • Equipment Cost: Digital radios and infrastructure can be more expensive.
  • Coverage: Dependent on digital network coverage, which may be less widespread than analog.

Summary of Differences:

  1. Frequency and Modulation:
    • Analog: Traditional VHF/UHF, AFSK modulation.
    • Digital: Same frequencies, digital modulation schemes (GMSK, C4FM, TDMA).
  2. Hardware and Setup:
    • Analog: Requires TNC or sound card interface, simpler setup.
    • Digital: Digital radios with built-in GPS/APRS, more complex setup.
  3. Network Infrastructure:
    • Analog: Uses digipeaters, simplex communication.
    • Digital: Uses digital repeaters and internet gateways.
  4. Data Throughput:
    • Analog: Lower data rates (1200 baud).
    • Digital: Higher data rates, more efficient spectrum use.
  5. Compatibility:
    • Analog: Broad compatibility with existing infrastructure.
    • Digital: Requires compatible digital equipment and networks.
  6. Usage and Application:
    • Analog: Local tracking, messaging, telemetry.
    • Digital: Long-distance tracking, efficient data transmission, internet integration.

Choosing between analog and digital APRS depends on your specific needs, existing equipment, and the infrastructure available in your area. Analog APRS is more universally accessible and simpler, while digital APRS offers advanced features and greater efficiency but requires compatible digital equipment and networks.

How to use APRS

Using APRS (Automatic Packet Reporting System) offers numerous benefits for amateur radio operators and other users. Here are some key reasons to use APRS:

  1. Real-Time Tracking
  • Position Reporting: APRS enables real-time tracking of mobile stations (e.g., vehicles, hikers, boats) by transmitting GPS coordinates. This is particularly useful for event organizers, search and rescue operations, and individuals who want to share their location.
  • Situational Awareness: Knowing the real-time locations of other stations can improve coordination during events, emergency responses, and group activities.
  1. Messaging and Communication
  • Text Messaging: APRS supports short text messages between stations. This can be a reliable way to communicate when voice communication is not practical.
  • Bulletins and Announcements: Broadcast important information to all stations within a network, such as weather alerts, event details, or emergency updates.
  1. Weather and Telemetry Data
  • Weather Stations: Many APRS stations are equipped with weather sensors, providing real-time weather data to the network. This information can be invaluable for local weather monitoring and forecasting.
  • Telemetry: APRS can be used to transmit telemetry data from various sensors, such as environmental monitors, equipment status, or even satellite data.
  1. Emergency and Public Service
  • Disaster Response: APRS is a valuable tool in disaster response, allowing responders to track resources, relay information, and coordinate efforts effectively.
  • Event Management: During public events like marathons, parades, and community gatherings, APRS helps organizers keep track of participants, volunteers, and assets.
  1. Global Connectivity
  • APRS-IS Integration: By connecting to the APRS-IS (Internet System), local APRS data can be shared globally, allowing for worldwide tracking and data access via websites like aprs.fi.
  • Cross-Network Communication: APRS gateways enable communication between different networks and systems, enhancing connectivity and interoperability.
  1. Educational and Experimental Use
  • Learning Tool: APRS provides a hands-on way to learn about radio communication, GPS technology, data protocols, and network infrastructure.
  • Experimentation: Amateur radio operators can experiment with different configurations, equipment, and technologies, contributing to the development and improvement of APRS.
  1. Integration with Other Systems
  • Smart Devices and Applications: APRS can integrate with smartphones, computers, and other devices through various apps and software, enhancing usability and accessibility.
  • Automation and Control: Use APRS for remote control and monitoring of equipment, such as repeaters, weather stations, and other automated systems.
  1. Community Building
  • Amateur Radio Community: APRS fosters a sense of community among amateur radio operators, encouraging collaboration, information sharing, and mutual support.
  • Public Engagement: Demonstrating APRS capabilities at public events can raise awareness and interest in amateur radio and its applications.
  1. Enhancing Radio Communication
  • Redundancy: APRS provides an additional layer of communication that can be critical when other systems fail.
  • Enhanced Functionality: Combining APRS with digital modes (like DMR, D-STAR, or System Fusion) offers advanced features and improved performance.
  1. Safety and Security
  • Personal Safety: Real-time location tracking can enhance personal safety during outdoor activities, travels, or in hazardous situations.
  • Asset Security: Track and monitor valuable assets, ensuring they remain safe and secure.

Conclusion

APRS is a versatile and powerful tool in the amateur radio world, offering benefits ranging from real-time tracking and messaging to emergency response and educational opportunities. Whether for personal use, community service, or technical experimentation, APRS provides valuable functionality that enhances communication, coordination, and safety.

Show your altitude with APRS

To show your altitude with APRS (Automatic Packet Reporting System), you need to ensure that your APRS setup is configured to include altitude data in your APRS packets. This typically involves using a GPS receiver that provides altitude information and configuring your APRS software or hardware to transmit this data. Here’s a step-by-step guide:

  1. Ensure GPS Module Provides Altitude Data
  • Built-In GPS: If your APRS-enabled radio has a built-in GPS receiver, check the user manual to ensure it provides altitude data.
  • External GPS: If using an external GPS receiver, ensure it outputs NMEA sentences that include altitude information (e.g., $GPGGA).
  1. Configure Your APRS Equipment

For APRS-Enabled Radios

  1. Check GPS Settings:
    • Make sure the GPS is enabled and configured correctly in the radio settings.
    • Ensure that altitude reporting is enabled (if there is an option for it).
  2. APRS Settings:
    • Access the APRS settings menu in your radio.
    • Look for options to include altitude in your APRS packets.
    • Save your settings and restart the radio if necessary.

Example: Yaesu FT-3DR

  • Menu > APRS > APRS Beacon TX > GPS Info: ON
  • Menu > APRS > APRS Beacon TX > GPS Beacon: ON

For APRS Software (e.g., APRSISCE/32, UI-View)

  1. GPS Configuration:
    • Connect your GPS receiver to your computer.
    • Configure the software to receive GPS data from the correct COM port.
  2. Include Altitude in APRS Packets:
    • Access the APRS settings in your software.
    • Ensure that altitude data is included in the APRS packets.
    • Save the settings and start sending APRS beacons.

Step-by-Step Guide to Show Altitude with APRS on an AnyTone 878

  1. Ensure GPS is Enabled and Getting a Fix
  • Turn on GPS:
    • Press the Menu button.
    • Navigate to GPS and select GPS On/Off.
    • Ensure GPS On is selected.
  • Check GPS Status:
    • Go to Menu > GPS > GPS Info to see if your GPS has a fix and is providing location data. Ensure you have a clear view of the sky for the best results.
  1. Set Up APRS
  • Enter APRS Menu:
    • Press Menu.
    • Navigate to APRS and select it.
  • APRS Settings:
    • APRS Mode: Set to Analog or Digital depending on your usage.
    • APRS TX Interval: Set your desired transmission interval (e.g., every 1 minute, 5 minutes, etc.).
    • APRS Beacon Type: Ensure it includes GPS data. Select Fixed if you want to send fixed position data or Mobile for moving stations.
  1. Enable Altitude Reporting
  • APRS GPS Report:
    • Navigate to APRS > APRS GPS Report.
    • Ensure that the GPS Report option is enabled, and it includes altitude data.
  • Set GPS Coordinates Format:
    • Go to APRS > APRS Coordinates Format.
    • Ensure it’s set to a format that includes altitude (typically, this is included by default).
  1. Configure the APRS Beacon Text
  • APRS Text:
    • Navigate to APRS > APRS Text.
    • Ensure the text includes information you want to transmit. The altitude is included in the GPS data packet automatically.
  1. Verify Your Settings
  • Check Beacon Transmission:
    • Go to APRS > Send Beacon to manually send a beacon and verify it’s transmitting your location and altitude data.
  • Monitor APRS Packet:
    • Use an APRS monitoring tool or website like aprs.fi to check your transmitted packets and ensure they include altitude data.

Example Configuration:

  1. Enable GPS:
    • Menu > GPS > GPS On/Off > GPS On
  2. Check GPS Fix:
    • Menu > GPS > GPS Info
  3. Set Up APRS:
    • Menu > APRS > APRS Mode > Select Analog or Digital
    • Menu > APRS > APRS TX Interval > Set to desired interval (e.g., 1 Min)
  4. Enable Altitude Reporting:
    • Menu > APRS > APRS GPS Report > Ensure enabled
    • Menu > APRS > APRS Coordinates Format > Ensure it includes altitude
  5. APRS Text:
    • Menu > APRS > APRS Text > Customize if needed
  6. Send Beacon:
    • Menu > APRS > Send Beacon to test transmission

Example of an APRS Packet with Altitude

An APRS packet with altitude data might look like this in the raw format:

CALLSIGN>APRS,TCPIP*,qAC,APRSFI:=3753.45N/12202.87W>123/045/A=001234

In this example:

  • CALLSIGN: Your callsign
  • 3753.45N/12202.87W: GPS coordinates
  • /A=001234: Altitude in feet (1234 feet)

Conclusion

Displaying your altitude with APRS involves ensuring your GPS receiver provides altitude data and configuring your APRS equipment or software to include this data in your transmitted packets. Once set up correctly, you can verify the transmission using an APRS client or online service to ensure your altitude is being reported accurately.

Conclusion

By following these steps, you should be able to configure your AnyTone 878 to include altitude data in your APRS transmissions. Always ensure you have a good GPS signal and verify your transmitted packets using an APRS monitoring tool to ensure the altitude data is included and accurate.

What is the APRS & GPS icons on an AnyTone 878 display?

On an AnyTone 878, the APRS and GPS icons on the display provide visual indicators of the radio’s status related to APRS (Automatic Packet Reporting System) and GPS (Global Positioning System) functionalities. Here’s what these icons typically represent:

APRS Icon

APRS Icon:

  • Purpose: Indicates the status of the APRS functionality.
  • Appearance: The icon usually looks like a small symbol that might include the letters “APRS” or a graphical representation associated with packet data.

Status Indications:

  • Enabled: When the APRS icon is displayed, it indicates that the APRS functionality is enabled on the radio.
  • Transmitting: Some radios might show a variation of the icon or an additional indicator to show when the radio is actively transmitting an APRS packet.
  • Receiving: Similarly, the icon might change or an additional indicator might appear when the radio is receiving APRS packets.

 

GPS Icon

GPS Icon:

  • Purpose: Indicates the status of the GPS functionality.
  • Appearance: The icon usually looks like a small satellite or a location pin symbol.

Status Indications:

  • No Fix: If the GPS icon is blinking or has an exclamation mark, it usually means that the GPS is on but has not yet acquired a satellite fix. This means the GPS is trying to determine your location but hasn’t succeeded yet.
  • Fix Acquired: When the GPS icon is steady, it means that the GPS has successfully acquired a satellite fix and is providing location data, including latitude, longitude, and potentially altitude.

Understanding the Icons

  • APRS Icon:
    • If the APRS icon is present and steady, APRS is enabled.
    • If the APRS icon is blinking or has additional indicators, it could signify active transmission or reception of APRS packets.
  • GPS Icon:
    • If the GPS icon is blinking, it means the GPS is trying to acquire a fix.
    • If the GPS icon is steady, it means the GPS has a fix and is providing location data.

Example Scenario:

  1. APRS Enabled with GPS Fix:
    • APRS icon is steady, indicating APRS is enabled.
    • GPS icon is steady, indicating a GPS fix is acquired and location data is available.
  2. APRS Transmitting:
    • APRS icon might show additional activity (like blinking) to indicate active packet transmission.
  3. GPS Searching for Fix:
    • GPS icon is blinking, indicating that the GPS is searching for satellites to acquire a fix.

Checking and Configuring Icons

To ensure these icons are displayed correctly, you may need to check your radio settings:

  • Enable GPS:
    • Menu > GPS > GPS On/Off > Set to GPS On
  • Enable APRS:
    • Menu > APRS > APRS Mode > Set to Analog or Digital

Conclusion

The APRS and GPS icons on the AnyTone 878 provide quick visual feedback about the status of these functionalities. Understanding these icons helps ensure your APRS and GPS are functioning correctly, aiding in effective use of APRS for location tracking, messaging, and other purposes.

7.9 GPS Positioning Function (optional with installed GPS)

  1. Press (Menu) to enter the main Menu.
  2. Select “GPS”.
  3. Select “GPS On”.
  4. MAIN MENU FUNCTIONS

» If the GPS is not positioning, it will display “No Fixed Position”, and the GPS icon shows a grey color. Move the radio to an open window or outdoors, and it will take a few minutes to connect to the GPS Satellites.

7.9.2 GPS Info

Method 1: Check GPS info from Menu

Press Info”. (Menu) key to enter Main Menu, select “GPS”, then select “GPS

Method 2: Check GPS info from programmed key

In the PC software, Public – Optional Setting – Key function, program a key as “GPS Info”, then press the programmed key to check the GPS info.

36 Digital DMR and Analog UHF/VHF Two Way Radio

7.9.3 Send GPS Information

  1. When the GPS is positioning successfully, the GPS icon shows a red color. Follow the above step to check the GPS info, press edit key to Text edit.
  2. Press Confirm, and it will display Send or Save. If you select Save, the GPS info will be saved as a draft message.
  3. Choose Send and it will display Contact list or Manual Dial.
  4. Select Contact list to choose a contact, press select to send the GPS info. or
  5. Select Manual Dial, input the DMR ID, press key to switch group ID or private ID, press to send the GPS info.

7.10 APRS Location Reporting(Supported by GPS)

(1) Upload Type

None: No APRS.

Sel A Aprs: Select analog APRS. Sel D Aprs: Select DMR APRS.

(3) Ana APRS Info

The received analog APRS information will be saved in radio for look back use. Click on “Ana APRS Info” will show the received APRS information. Click on “Delete All” will clear the information.

(2) Ana APRS

PTT Upload: Set the PTT transmit method.

  • Off: Not transmit APRS.
  • Tx Start: Transmit analog APRS when press the PTT.
  • TX End: Transmit analog APRS when release the PTT.

Upload Power: Set the transmit power. Upload frequency: Set the transmit frequency. Upload text: Set the text to be shown on aprs.fi

(4) Digi APRS

PTT Upload: Set the PTT transmit method.

  • Off: Not transmit APRS.
  • On: Transmit DMR APRS when release the PTT.
  1. MAIN MENU FUNCTIONS

Digital DMR and Analog UHF/VHF Two Way Radio 37

(5) Digi APRS Info

The received APRS information will be saved in radio for look back use. Click on “Digi APRS Info” will show the received APRS information. Click on “Delete All” will clear the information.

(6) Intervals Set

This function allows you to set the analog APRS or DMR APRS auto transmit at fixed times.

(7) Upload Beacon

GPS Beacon: The APRS will transmit the GPS data, only if the GPS is set to on first, then GPS must also successfully lock on the satellites.

Fixed Beacon: The APRS will transmit the fixed beacon data. Someone can transmit the fixed beacon without setting the GPS on. The fixed beacon location information should be set in CPS firstly.

Note: More setup are available by PC software only. CPS-Tools-Options APRS, you have to check on the APRS box first to get APRS menu add to the left Digital menu.

(APRS is a registered trademark of Bob Bruninga, WB4APR)

DMR Tech Net