This week, we check out two APRS applications that are particularly useful this time of year when many folks are traveling to Vacationland and trying to dodge nasty weather.

I do APRS (Automatic Position Reporting System) 24/7. My APRS digipeater is on all the time and my mobile APRS station is on the air whenever I am driving my land barge. I also watch what is going on in the APRS world by subscribing to a lot of APRS email lists. As a result, I am very aware of the latest wonders that are developing in APRS and will tell you about them every once in awhile.

Steve Dimse, K4HG, has built a couple of new APRS Internet applications that are excellent! One is his breadcrumb application that displays the breadcrumbs dropped by a mobile APRS station as it traverses the Earth. The dropped breadcrumbs represent the station's position packets that were relayed via the APRS network and the Internet to Steve's "findu" server. To view the breadcrumbs of a particular station, use the URL http://www.findu.com/cgi-bin/breadcrumb.cgi?call= with the call sign and SSID of the station you wish to view following the equal sign. For example, http://www.findu.com/cgi-bin/breadcrumb.cgi?call=wa1lou-8 displays the breadcrumbs dropped by my mobile APRS station cruising around central Connecticut.

Watch your APRS friends drive to Vacationland this summer by using K4HG's breadcrumb application.

Appending &start=sss and &length=lll after the call sign and SSID commands the server to look back in its database the number of hours (sss) specified in the start parameter and begin displaying the breadcrumbs for the number of hours (lll) specified in the length parameter. For example, appending &start=480&length=36 after the call sign and SSID causes the server to display the breadcrumbs for the 36-hour period starting 480 hours (20 days) ago. Appending &xsize=xxx, &ysize=yyy, and &zoom=z after the call sign and SSID changes the width, height, and magnification of the displayed map, respectively. The maximum value for xsize and ysize is 1000, while zoom may be set to either 1 or 2.

K4HG's other new APRS application displays the National Weather Service Doppler radar image for approximately a 150-mile radius surrounding a specified APRS station. Use the following URL: http://www.findu.com/cgi-bin/radar-find.cgi?call= with the call sign and SSID of an APRS station plugged in after the equal sign and your browser displays the weather radar image for the specified area. For example, try http://www.findu.com/cgi-bin/radar-find.cgi?call=wa1lou-15 to view the weather for the area surrounding my APRS digipeater (WA1LOU-15).

Using a wildcard (an asterisk in place of the hyphen and SSID) displays the weather radar image for the area surrounding all APRS stations using a particular call sign. For example, using http://www.findu.com/cgi-bin/radar-find.cgi?call=wa1lou* displays the weather for the area surrounding both my digipeater and the APRS station in my land barge, i.e., WA1LOU-15 and WA1LOU-8, respectively.

(You may also want to check out the National Weather Service Radar Information Web page to learn how to interpret the data displayed by the radar weather image.)

Until next time, keep on surfin'.

Editor's note: Stan Horzepa, WA1LOU, of downtown Wolcott, Connecticut, is an ARRL Life Member and an incessant contributor to QST and QEX (514 pieces in 23 years), not to mention the author of five ARRL books and contributor to a bevy of other ARRL titles. First licensed in 1969 as WN1LOU, he upgraded to WA1LOU in 1971. Stan began using computers with Amateur Radio in 1978 when he bought a Radio Shack TRS-80 Model I computer and wrote BASIC programs to dupe contests and calculate antenna bearings. A virtual beach boy, Stan has been surfing the radio dials as long as he can remember, however, instead of surfing all over Manhattan and down Doheny Way, he now surfs the Internet searching for that perfect page. To contact Stan, send email to wa1lou@arrl.net.

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