Friday, January 28, 2011

VHF propagation alerts over APRS

I have just set up an ANSRVR notification group (the APRS equivalent of an email reflector) called CDGVHF. The purpose of the group is to alert interested subscribers in the Cumbria, Dumfries and Galloway area to possible openings on the 6m, 4m, 2m and 70cm bands.

The APRS alerts make use of the email alert service of DX Sherlock which sends alerts of possible band openings customized to the subscriber's location, based on DX Cluster spots and other reverse beacon information. I have set up a subscription to send alerts of possible band openings workable from the IO84 grid locator to a special email address on the G4ILO's Shack web server. Using a feature of the cPanel web hosting, the email is "piped" to a script written by me in the PHP language. This extracts the subject header of the email which contains a succinct description of the alert, shortens it as much as possible and then sends it as a message to the CDGVHF ANSRVR group, which then forwards it to all interested subscribers.

Why is this better than just subscribing directly to receive the alert emails? Because I can now receive the alerts on my APRS-equipped hand-held, which should greatly reduce the chance of missing a good band opening because I wasn't in the shack at the right moment.
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