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 what website I look at (APRS-IS related). Why?

The websites you compare are not collecting packets from the same APRS-IS servers. Each APRS-IS server performes duplicate filtering, and which packet that is considered to be a duplicate may differ depending on which APRS-IS server you ask.

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 source. APRS data can be received from APRS-IS.

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

If you do not want your APRS data to be publiched on APRS-websites 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.

How is the coverage map created?

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.

The coverage map consists of two parts:

• The heatmap that shows all recorded coordinates.
• The interpolated max range plot polygon that shows the coverage.

The max range plot is created by:

1. We exclude positions that have a distance that is further away than the 95th percentile.
2. We use a convex hull algorithm to get a polygon of the covered area.
3. We add some padding to the area received in the previous step. This step is just used to make the polygon look a bit nicer.

Can you tell me how the marker logic works?

Okay, let me tell you more about our brilliant marker logic :-)

• 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 link to this website?

Yes absolutely!

• To link to a station tracking map view, use one of the following alternatives:
  https://www.thiswebsite.com?sname=STATION-NAME
  https://www.thiswebsite.com?sid=STATION-ID


• To link to a tracking map view for multiple stations, use one of the following alternatives:
  https://www.thiswebsite.com?snamelist=STATION-NAME-1,STATION-NAME-2,STATION-NAME-3
  https://www.thiswebsite.com?sidlist=STATION-ID-1,STATION-ID-2,STATION-ID-3


• To link to a map view, centered on a position, use the following:
  https://www.thiswebsite.com?center=LATITUDE,LONGITUDE&zoom=ZOOM-LEVEL

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)

What is this site built on?

This website is built upon on a variety of cutting edge tools and technologies. Those technologies include APRS TrackDirect, APRSLib, as well as Apache, PHP, PostgreSQL, and others.

I have a question. Who may I contact?

Maintainer of this website is YO8RXT.