So, one of the main problems with real-time telemetry is that it deteriorates over long distances, and the transmitting frequency is affected quite a bit with temperature changes. I thought about using plain old serial comms over a 900MHz link (similar to Natrium's launch) but that didn't work very well, and also, the UK is stringent on it's transmission rules. It turns out there are only a few frequencies 'allowed'; a tiny range in 434 (@ 10mW) and 869 MHz (@500mW). This rules out the 900 option completely, and many other higher power transmitters which may be able to 'blast' the signal hundreds of miles without issue. Ideas were needed...
The UKHAS site has plenty of hints, tips and pointers. The standard used here is
RTTY, and suits this application of low power, long range communications.
I also thought I could add a 2.4GHz micro cam to the payload (I know the range won't be amazing - but could be good?) and then I thought I could add the same Gumstix micro computer as the Halo project; having a webcam take a series of pictures. The payload and complexity was increasing....
anyway, bought the Gumstix:
