Frequently Asked Questions

What is APRS?

APRS (Automatic Packet Reporting System) is a digital communications system that uses packet radio to send real time tactical information. The APRS network is used by ham radio operators all over the world.

Information shared over the APRS network is for example coordinates, altitude, speed, heading, text messages, alerts, announcements, bulletins and weather data.

My latest packet seems to be using different path's depending on which APRS website I check. What is happening?

The APRS-IS internet backbone is made up of dozens of intepdendent. interconnected servers that relay packets across the intenet. It is highly unlikely that any two websites are aggregating data from the same server, this there will always be a discrepancy of several seconds, even a monite. As you compare timestamps on other sites, know that their packets are not likely from the same APRS-IS server as ours. In addition, each APRS-IS server performes duplicate filtering; those duplicates may differ depending on which APRS-IS server they are connected to.

How accurate is the position or speed data that I see here??

More often than not, the position and/or speed data presented here is accurate. We display the information as it's transmitted by the sending station. Positions can be wrong due to data corruption both in the over-the-air transmission path as well as the APRS internet backbone. Stations can also intentionally inject errors into their location (i.e Position Ambiguity) in order ot protect their privacy.

Where does the displayed data come from?

On each station you can see the specified data source (APRS, CWOP, etc.). APRS data can be received from APRS-IS, CWOP-IS or OGN (and more). We adhere to OGN's 24 hour storage limitation so no data beyond 24 hours is available for that source.

Can you tell me how the marker logic works?

As with many things in life, the answer is fairly complicated. Let's break it down...

• We have a speed limit filter and other filters that sorts out packets that has a faulty position.
• If a moving station sends a packet that is sorted out by our speed limit filter the packet will be marked as unconfirmed, if we later receive a packet that confirmes that the station is moving in that direction, the previous packet will be confirmed then.
• If a station moves in one area and suddently appear in another area the two tails will be connected by a dashed polyline.
• A moving station that reports it's speed and direction will have an animated direction polyline (will be hidden after 15min).
• The dotted polyline shows the packet transmit path, will be shown when you hover over a marker or a "dotmarker". If a station in the path hasn't sent a position packet in a long time it will show up for some seconds and than disappear again.
• Note that the time-interval specified in the station info-window (on the map) is how long a station has been on that location without any downtime longer than 24h.

Can I use a map that I map created in Google My Maps?

Yes you can. Follow these steps...

1. Open your map at Google My Maps.
2. Look at the current URL and try to find a value named mid. Copy that value!
3. Open this website. Add "&mid={the mid value}" to the end of the URL.
4. Press Enter!

How is the coverage map created?

The coverage map is utilizes several formulas to extrapolate the data that is presented visually.

Note that the coverage map is only available for receiving stations, it tries to show from which area the station is able to receive packets.

Can I prevent my data from being displayed on websites such as this?

Answer for APRS-IS/CWOP-IS and others (except OGN)

If you do not want your APRS data to be captured and published on APRS-websites such as this, you can append NOGATE to the end of your path (or use RFONLY). If your digipeater path is WIDE1-1,WIDE2-1, you just change it to WIDE1-1,WIDE2-1,NOGATE.

Answer for OGN (Open Glider Network)

Not all information that is sent to the Open Glider Network is published.

Aircrafts that meet any of the following condition is not shown at all.
→ Has the "no-tracking" flag in FLARM device configuration set.
→ Has activated the setting "I don't want this device to be tracked" in the the OGN Devices DataBase.

This website will only display information that can be used to identify an aircraft if the aircraft device details exists in the OGN Devices DataBase, and if the setting "I don't want this device to be identified" is deactivated. If the website is configured to also render aircrafts that does not exists in the OGN database, the aircraft is given a temporary name that is only used for a maximum of 24h (to make sure it can not be identified).

Read more about how to "Opt In" or "Opt Out" here.

What is CBAPRS then?

CBAPRS is the Citizen Band Automatic Packet Reporting System. Unlike regular APRS, this reporting system is not reserved exclusively for amateur radio operators. Anyone legally able to operate on the European Citizens Band radio frequencies may participate. More information is available on the official CBAPRS website.

Can I link to this website?

Of course, in fact we love when people link to us. Linking to us helps to build interest and traffic to our APRS services. You can directly link to many pages by copying the QuickLink (link at the footer of many pages). Alternatively, you can build your own links with the details below.

• To link to a station tracking map view, use one of the following alternatives:
  http://aprs.to?sname=STATION-NAME
  http://aprs.to?sid=STATION-ID
• To link to a station overview (details view), use one of the following alternatives:
  http://aprs.to/station/station.php?c=STATION-NAME
  http://aprs.to/station/station.php?id=STATION-ID
• To link to a tracking map view for multiple stations, use one of the following alternatives:
  http://aprs.to?snamelist=STATION-NAME-1,STATION-NAME-2,STATION-NAME-3
  http://aprs.to?sidlist=STATION-ID-1,STATION-ID-2,STATION-ID-3
• To link to a map view, centered on a position, use the following:
  http://aprs.to?center=LATITUDE,LONGITUDE&zoom=ZOOM-LEVEL

Who runs this website?

This website is built and maintained by Steve White, N2RWE.

Can my data be deleted from this website?

Registered users can request their account be closed at any time. We will delete all data associated with closed accounts after 90 days. Data for a specific user/station that was received from 3rd parties (i.e. APRS, CWOP, etc.) cannot be deleted as that data is derived from public data sources. The exception is for stations in the OGN network where all data for all stations is automatically deleted after 24 hours.

What is this site built on?

This website is built upon on a variety of cutting edge tools and technologies, woven together by carefully crafted, custom written software. Those technologies include the core of the APRS-IS system aprsc, as well as APRS TrackDirect, APRSLib, as well as Apache, PHP, MariaDB, PostgreSQL, Proxmox, and others.

Don't see your question here?

APRS offers many diverse applications and use-cases. We've tried to cover many of them here. If you don't see your specific question answered here, you can Contact Us and we will try to help.

What browsers do this website support?

Our goal is that this website should work on all browsers that supports websockets (an HTML5 feature). The following browser versions (and newer) should adequately supports the websocket-protocol and be compatible with our site.

• Internet Explorer 10 (released 4/9 2012)
• Edge 12 (released 30/3 2015)
• Firefox 11 (released 31/1 2012)
• Chrome 16 (released 25/10 2012)
• Safari 7 (released 22/10 2013)
• Opera 6.1 (released 5/11 2012)
• iOS Safari 6.1 (released 28/1 2013)
• Android Browser 4.4 (released 9/12 2013)
• Blackberry browser 7 (released 1/1 2012)
• Opera Mobile 12.1 (released 9/10 2012)
• Chrome 53 for Android (released 8/9 2016)
• Firefox 49 for Android (released 20/9 2016)
• IE Mobile 10 (released 20/6 2012)
• UC Browser 11 (released 17/8 2016)
• Samsung Internet 4 (released 19/4 2016)