This is a section of the Aprs.fi user guide.
My position is not showing up on aprs.fi
If your APRS position is not showing up on the site, the most common problem is incorrect symbol setting in the tracker. Please check the raw packets to see the error messages (enter your callsign and click on Search). If you have a problem with the symbols, please check the APRS symbol configuration page on the APRS Wiki.
You should also check if your positions show up on other sites such as DB0ANF and findu.com. If the positions are not showing up on the other sites, the problem is most likely in your tracker's configuration or the local APRS network (or lack of it). Please get in touch with either another local APRS user, or your tracker's user group. Many of them are listed on the google group's front page.
If the positions are showing up on other sites but not aprs.fi, please check the raw packets again. aprs.fi is sometimes a little bit stricter than others about the packet syntax correctness, especially when it comes to symbol settings, and might reject a broken packet which others digest happily. Sorry about that.
My vehicle's position is jumping back and forth to old positions
This can happen due to many reasons, including:
- Your tracker transmitting packets very often, increasing the chance that they arrive at aprs.fi in the wrong order
- Your tracker transmitting packets with a very long digipeater path, increasing the chance that they arrive out-of-order
- A dysfunctional digipeater buffering packets for a long time before retransmitting them
- An igate with a bad Internet connection buffering packets before getting them on the APRS-IS
- A broken digipeater or igate mangling the contents of packets, so that the duplicate packet looks a little bit different than the original and won't be detected by the duplicate detection algorithms
The first two are easy to fix. The second two are harder to track down, but their effects can sometimes be mitigated by reducing the transmitting rate and using a shorter path, so that the packets do not go to a faraway broken digipeater.
aprs.fi tries hard to filter old positions, but sometimes they still get through. Because APRS packets do not contain sequence numbers and usually do not contain timestamps, it's hard or impossible to properly catch the duplicates.
There is a long blog post describing issues with duplicate and delayed APRS packets on the aprs.fi blog.
The real-time map does not show
The page layout looks funny or strange
At my workplace, there are sometimes problems with the web proxy server, and the CSS files defining the style and layout fail to load, resulting in a broken layout. This can be cured by doing a "power reload" by pressing CTRL and clicking the reload button (on IE). On Firefox, it's SHIFT-reload, and on Mac Firefox, you need to keep the Apple (Command) key down while clicking the reload button. Alternatively, you can try clearing the browser's cache (temporary files).
If this doesn't help, you're probably running Internet Explorer 6 or Internet Explorer 7. I strongly feel that IE6 must die, and everyone should upgrade to Internet Explorer 8 or whatever else. It's very much broken, and it takes an awful lot of time for me to make the site work with IE6. Others just work. Some layout and placement problems are still there and I can't make them go away, since IE6 is buggy. IE7 has some bugs left, too, and IE8 is OK.
If you're running a modern browser and still see layout problems (or any other problems), please let me know through the google group.
The real-time map is slow
The map is faster when there are fewer markers visible – just try zooming in a bit. In Preferences => Filtering you can hide some target types you're not interested in. Selecting Show with track instead of Track + waypoints will hide the small red dots indicating transmitted positions along the track, which will reduce the amount of markers and might give a considerable speed-up.