My daughter bought me a BeeLine TX radio direction finding beacon for Christmas. The plan is to mount it inside the payload bay of various rockets so that I can find them after launch. This uses a PIC 16F688 processor and a CC1050 transmitter and sends FM-encoded beeps and Morse code ident strings. It's tiny and runs for a long time off a Li-Po battery.

The BeeLine TX came pre-programmed to transmit at 433.920MHz and ident as 'KD7SQG'. I wanted to move it to 440.700MHz and ident as 'KD7SQG ROCKET', but the configuration utility provided was Windows-only.

Fortunately, Greg Clark, the person behind Big Red Bee, released the source code for the firmware under the GPLv2 and provided full schematics as well.

I was able to read through the code and construct a simplistic programming utility, also released under the GPLv2 and available via git as beelinetx. It doesn't do much yet, just allows the configuration of the frequency and transmitted message string.

I'd like to thank Greg for building the BeeLine TX, making the sources and schematics available and also for answering questions over email about some subtle aspects of the frequency calibration.

Now to wait for the weather to clear and go take it flying.