Friday, August 29, 2008

iPhone working (slightly)

iPhone support seems to be working slightly better now, but there are still some issues. They can be partially in Google's Maps API code, and partially in Apple's Safari code, and the fixes need to be done there.

There are bug reports in Google's bug tracker for the issues (I filed a couple, and there are a couple more submitted by others). I'm hoping that the good people at Google will fix them, or persuade Apple to fix their bugs.
Thanks go to Rasmus (a colleague at the $office) for borrowing his iPod Touch for a couple hours. If one of you happens to have a spare unit, you can find my address at qrz.com. :)

Update: I have obtained an iPod Touch for debugging, and enhanced iPhone support for APRS!

Wednesday, August 27, 2008

OH7LZB interviewed in the Japanese CQ ham radio magazine

Oba, JA7UDE interviewed me for the Japanese CQ ham radio magazine. The interview was published in the 2008/9 edition, which came out last week (list of contents, PDF). They've previously interviewed other software authors and APRS people, including Byon Garrabrant, N6BG (Byonics/TinyTrak) and Simon Brown, HB9DRV (Ham Radio Deluxe).

He mailed me a couple of the older magazines, and they seem really nice - there is so much technical content in there, and so few ads in comparison. Lots of long "how-does-this-stuff-work" articles with friendly and funny illustrations, and plenty of "how-do-I-build-this" articles. They're thick (around 150 pages), and unlike some other ham magazines, they're not half full of advertisements. Too bad I can't read Japanese. The schematics and pictures are almost enough to complete some of the projects, though.

Kenwood using aprs.fi @ Ham Fair 2008, Tokyo


The JARL Ham Fair 2008 was held in Tokyo last weekend. Oba, JA7UDE took these nice photos of Kenwood showing off aprs.fi on their big screen, together with their new APRS-capable TM-D710A mobile rig.

Oba reports that they displayed aprs.fi in both Japanese and English modes, and they seem to have run Google Earth with the aprs.fi overlay, too. Very cool indeed, thank you Kenwood for the nice little extra publicity!

Thanks to SQ6NTI for the link.

Monday, August 25, 2008

APRS PHG circles

I've just installed an initial implementation of PHG (power-height-gain) circles on the live APRS map. They can be enabled by clicking on the new PHG icon in the top right corner. PHG circles are shown for APRS stations which are transmitting the PHG extension in their comment text.

The first click enables half-sized circles, which are supposed to resemble the reach of an APRS digipeater from a mobile user's point of view (small antenna at low height, lots of fading and multi-path propagation). The second click enables full-sized PHG circles which are calculated according to the APRS 1.0 specification, and might be quite optimistic for mobile users, but more realistic for connectivity between digipeaters and other installations with better antennas. Not surprisingly, the third click disables PHG circles again.

If you'd like to add the PHG extension to your digipeater configuration, please try the NashvilleAPRS PHG Calculator!

Update: There's a better PHG calculator at M0CYP's site which does PHGR - PHG with beacon Rate. aprs.fi doesn't display the rate yet, though.

Sunday, August 24, 2008

Firefox 3 bug workaround, try 2

I've just installed an updated version of my AJAX JavaScript code on aprs.fi. It seems to work better for me on Firefox 3 - the live map no longer gets stuck in the 'updating' state once there are too many targets visible, or a very long track line.

Please let me know if this change fixes this bug for you by posting a comment after this post. I hope it didn't break any other browsers - I tried the usual FF2/FF3, MSIE6/7, Opera, Safari, Konqueror.

Thursday, August 7, 2008

7-day track views

I've just added code to show up to 7 days of track data on the map when looking at a single tracking target. Thanks to Steve, K9DCI on the APRSSIG for reminding me about this. :) This only works for single target views, since longer time range searches for global data would place a heavy load on both the database, as well as the web browser.

Showing the track wasn't hard. As usual, getting the user interface to work on MSIE was. Found out the hard way that the disabled attribute isn't working on the select list used for time range selection, so I had to resort to completely removing entries which are not usable.

Update on Friday, 8th of August: I just realized it doesn't work with the date selection menu - I will fix that one later.

Saturday, August 2, 2008

Performance issues during the past few days

I'm currently in Mexico, performing at the Zacatecas International Folklore Festival. I have been in Mexico for just about two weeks now, first having a holiday in Mexico City and Oaxaca, and now playing guitar with the Finnish folk dance group Petkele at the festival. So, I haven't been paying much attention to the aprs.fi service.

But today I got an automatic alarm about the service being pretty slow, so I checked the systems and found out that my recent status message view changes had introduced a memory leak in the backend system, and the master server was swapping pretty much. This has caused some slowness and data loss over the past 4 or 5 days, as you can see in the statistic graphs. I restarted the data collector processes to regain the leaked memory, and will look into this in more detail once I'm back home. It leaks so slowly that it should work just fine for a week.

I'll have to tune the alarm system to be a bit more sensitive for this kind of slowness. I think I've forgotten to set up the "too much swap IO" alarm, too.