aprs.fi presentation in Friedrichshafen, Ham Radio 2012

I'll be giving a lecture titled Advanced tricks and new features of aprs.fi at Ham Radio 2012, Friedrichshafen.

In this session I will demonstrate usage of advanced aprs.fi features beyond basic callsign lookup. New features and plans for the future will be announced.

The session will end with a Questions & Answers section and discussion. There should be plenty of time for that.

Time: Saturday, 23 June 2012, 14:00, about 1 hour + discussion
Place: Room/Raum Paris

Beware, it's a 15-minute walk from the center of the fun. The place is huge, so distances are noticeable.

It's not listed in the official program yet, since I got the idea of doing a presentation a bit late and the program had already been sent to be printed, but the organizers managed to find a room for us. Thank you Thilo! Since it's not in the official program, please let other APRS folks know about it when you bump into them on Friday. Thanks!

aprs.fi connected directly to aprs2.net hubs

I'm happy to announce that aprs.fi has tonight been directly connected to all of the APRS Tier 2 Network hubs. Two frontend servers, APRSFI-C1 and APRSFI-C2, are now connected with read-only connections to the five T2 hubs (T2HUB1 to T2HUB5), which act as the backbone of the aprs2.net network. This should provide a very stable and trouble-free connection between aprs.fi and the APRS-IS network.

Before this change aprs.fi was connected to a single APRS-IS server (usually T2FINLAND) and collected packets from that server alone. That server, in turn, is connected to a single T2 hub. Sometimes that connection could have some trouble and be disconnected for a few minutes, causing some packets to be lost. Recently a misconfiguration within the T2 network caused intermittent but severe packet loss for a few users for a long time. Having redundant, parallel connections to all of the servers should provide aprs.fi with copies of all packets even if some parts of the network have issues.

The fact that aprs.fi was usually connected to T2FINLAND also caused many users to prefer that server, which in turn caused a high load to the single server. Also, if that server would have had a hardware failure, all of those users would have lost connectivity to the APRS-IS. aprs.fi would have automatically switched to another server. Right now, T2FINLAND has 210 clients connected, while most other servers only have 30 to 100 clients. The Tier 2 network currently has a total of 4005 clients connected to the 86 servers in 31 countries.

If you're using T2FINLAND (finland.aprs2.net), or if you have configured your server to connect to any other single server, please reconfigure your system to use one of these Regional Rotate Addresses:

Europe and Africa: euro.aprs2.net
Asia: asia.aprs2.net
North America: noam.aprs2.net
South America: soam.aprs2.net
Oceania: aunz.aprs2.net

Check out the map of T2 servers and the rotate address distribution on the aprs2.net home page!

All of the regional rotate addresses will make your client connect to one of the nearly servers which have recently been automatically tested to be available and working. When that server fails, your client will automatically connect to some other server. All of the servers will provide equally good connectivity to aprs.fi. Starting tonight, T2FINLAND is not better in that respect than any of the others.

I repeat: Do not connect to finland.aprs2.net. If you're in europe, use euro.aprs2.net instead. T2FINLAND's server hardware will eventually break (we found it in the dumpster), and your igate or client software might be disconnected for a long time until someone gets to fix the server. Unless, of course, you use a regional rotate address, in which case you'll be automatically rerouted to a working server.

Thanks to all the Tier 2 operators for making this possible!

Linking parameters fixed and proper "Show all" button

The "others" and "timerange" parameters described on the Linking page should now work again. They were broken since the anchor navigation upgrade. Thanks to Oba JA7UDE for the bug report!

To properly fix how the "others" parameter  works I also added a new "Show all" button which is now quite a bit more  sensible than the old "Show all" link:

• The button is disabled and greyed out when it really doesn't do anything (like, when you're not tracking a station and all stations are displayed anyway)
• "Show all" can now be toggled between on and off, not just on
• The button visually indicates whether it's on or off (depressed or not)

Real-time telemetry and graph value lookup

I just finished installing an upgrade on aprs.fi. I had forgotten a configuration change that needed to be done with this upgrade, and the web service stopped working at 19:16 UTC. I had some trouble finding the problem, and managed to fix it at 19:38 UTC. That was completely unnecessary, sorry for the trouble. It should have been a routine upgrade requiring only a minute of downtime or so. Data collection was not interrupted.

The upgrade made the telemetry graph page update itself automatically as new values come in from the station, just like the weather page does. Just look up a telemetry station and leave the graph page open and the contents will be magically updated!

The grapher engine got a little upgrade which enables graph value lookups on all graphs. Just hover the mouse cursor above a graph and the labels will display the values reported at that time. While the pointer is between reported values it will display an interpolated value.

The real-time map's data refreshing algorithm got some updates and fixes.

I did a few updates on strings too, and the translations need to be updated. At least on the moving stations page I had to split a very long string to two short ones.

Telemetry display improvements

After attaching some 1wire temperature sensors to the USB port of my D-Link DIR-825 WLAN router running OpenWRT, and making aprx transmit the temperatures in the new base91 comment telemetry format, I felt like improving the telemetry display on aprs.fi a bit.

Current telemetry values are now shown in the info balloon of a station on the real-time map.

I always thought that many telemetry transmitters are only utilizing a few channels, and the other channels should not be shown. So here goes, now you can configure which channels are shown. If any channel names have been sent using the "PARM." message, only those channels (and bits) are displayed in the current telemetry values summary. If no names have been sent, all 5 analog channels and 8 bits are shown.

The telemetry coefficients transmitted with the EQNS. message now stores 5 decimal digits instead of 3. Base91 comment telemetry supports 13 bits of resolution (values 0 to 8280), which often needs to be scaled down to a range such as -55...+125C for temperature. More decimals in the multiplier and exponent parts help in making it accurate.

Dead reckoning and radio horizon circles

This large passenger boat is actually
making some turns between the islands.

Today aprs.fi got a simple implementation of dead reckoning. Moving stations which have announced their position, speed and course within the past 30 minutes will show a blue line extending from the latest announced position. The line indicates where the station would be right now if it proceeded on that course at exactly the same speed.

To limit the performance impact of this feature the DR indicator will be shown for a single station at a time. Click on a station to enable it. It's also enabled automatically for a tracked station.

Naturally it'll show some rather bogus estimations for vehicles which have stopped moving but have not transmitted a new packet with a speed of 0. Most trackers installed in cars loose their power input before they have a chance of transmitting a packet at the parking spot.

A plane flying at 2648 feet, and the digipeaters
and igates which have received it.

Flying stations having a "flying" symbol such as airplane or balloon will have two circles drawn around them. A larger blue circle indicates the sea-level horizon from the current altitude of the station. A smaller green circle indicates the area where the station can be seen at an elevation larger than 5 degrees.

The circles are useful for estimating the distance at which the station can be heard, which can be of use for tracking teams of high-altitude balloons. It also gives pilots an idea of the large amount of digipeaters and igates in range.

The circles are drawn for stations having a suitable symbol when the altitude is over 100 meters. Other stations will also get the circles when their altitude reaches 1000 meters.

aprs.fi upgrade on Monday 2012-03-19

aprs.fi will be upgraded on Monday 2012-03-19. Some downtime should be expected, starting around 9 AM local time (0700 UTC). If you can find some bugs in beta.aprs.fi, this is the time to report and get them fixed before they make their way to aprs.fi! Here's the long list of changes included in the upgrade. It's so long that, as usual, some new bugs will probably pop up. Please report them on the discussion group and I'll try to get them fixed right away.

Anchor navigation and more AJAX

Achilles (left) and Ajax (right) play a board game with
knucklebones on this late 6th-century lekythos, a type of
oil-storing vessel associated with funeral rites. Photo taken
in Musée du Louvre by Marie-Lan Nguyen, 2011
(CC by attribution, Wikipedia/Wikimedia).

The technical implementation of the navigation in the real-time map has been completely changed. In the new model the map page is not reloaded from the servers and initialized again from scratch every time an user changes the view by searching for a new callsign or an address. This AJAX magic will make callsign searches and other view modifications considerably faster, especially on slow computers and slow connections such as mobile devices. It'll also reduce load on my and Google's servers. And make the browser's bookmark functions and the back button work better than before.

All of the links used by aprs.fi to refer to specific map views have changed, but the traditional ones documented on the linking instructions page will keep working, and I encourage you to use them as before - they're not going anywhere.

Try searching for OH2K and OH2TI one by one again and again, and you'll notice both the improved loading speed, and a nice panning effect. It'll pan whenever the newly searched station is close enough to the current view.

Improved address search

Address search has been improved to make a better use of the data returned by Google's API. A marker for the result is now only shown if the result is accurate (such as a street, or a house number on a specific street).

Address search will also adjust the zoom level - "Finland" or "Pohjois-Karjala" or "USA" should actually fit the specified region in view. The zoom levels come from Google and I can not make it any smarter than that (yes, "USA" will zoom out a bit too much). But it's certainly better than it was (fixed zoom level after address search).

Improved response times

When you make changes to the real-time map view, for example by zooming out or selecting a time range, aprs.fi will now react much more quickly.

New time range back/forward buttons

When a station is tracked, there are now two new handy additional arrow buttons to jump the time range back and forward. If you have selected an arbitrary range, it will jump the same amount back (select a week, and it'll jump to the previous week). Otherwise it'll select the current whole day (UTC 00:00:00 to 23:59:59 - sorry, no local time support yet) on the first click, and the following clicks will jump by 24 hours.

Sharper map graphics on iPad/iPhone

The scaling of the web page was tuned to switch automatically so that map graphics are not blurred on the iOS devices, especially when the device switches between landscape and portrait orientation.

Other small things

Searching for "OH2RDK" will now give a proper "there are other SSIDs available although this one doesn't exist" response.

aprs.fi now uses a new version of the Google Maps API, bringing in some visual updates and speedups from Google.

An old bug which makes stations disappear after a quick zoom-in-and-back-out operation (and some other cases) has been fixed.

The "street view is off by 200 meters" bug is fixed. Also, the map should stay centered when Street View is enabled or disabled.

The ruler tool now displays distances shorter than 1 km in meters to allow measuring short distances.

When a station is tracked on a mobile device, the info balloon does not automatically pop up and block the whole view.

Raw packets view in decoded mode displays the position packet's type (compressed, mic-e...).

Tuned digipeater/igate "heard" map to collect more data and leave less gaps in the map.

Support for new major version of the database server (SQL syntax changes).

CSRF security fixes were implemented in many places.

Some rough corners have been rounded up (literally), and a few shadows have been cast (again, literally).

Does aprs.fi feel slow?

Be sure to try it with a modern, quick browser such as Google Chrome, Safari or Internet Explorer 9. If you're upgrading from Firefox or an older Internet Explorer, you'll be surprised by the difference it makes.