As part of my slow, arduous march toward doing a high altitude balloon launch, I acquired some super cheap wireless modules from sparkfun.com. Sadly, I haven’t had time to play with them much, but here’s someone who has. I am more interested in using these tiny transmitters as back up beacons, but the information is still quite useful.
What do you mean by “back up beacons”?
The highest range mentioned is 500 feet, so probably not for a balloon telemetry link.
Or would you be using it for finding the payload once it’s landed somewhere?
Or for a short-range link pre-launch?
I don’t know why you’d want to use these if you already have a long-range radio. Why not avoid the complexity and weight?
Clearly I have missed something. My apologies.
Later,
Doug
While the highest range mentioned is 500 feet, simple detection (especially using a high gain antenna in a radio detection type application) can probably be done well out to 5x that or more. If all goes well, I should be within that radius based upon the APRS payload which should send out position reports every 30 seconds or so until it hits the ground.
The weight of these things is just a few grams, plus whatever battery power we need. Very minimal. It mostly is just to provide a level of redundancy.
When I get around to it, I’ll probably run some dry run “direction finding” tests to show how this might be helpful, and put them up on youtube.
I have squeezed a range of about 100 miles (160 km) out of those small 433.920 MHz TX modules. All it takes is a resonant antenna on the balloon flight unit and a good receiver and a Yagi antenna on the “satellite” ground station. The most recent case in point was our CarrollSat-1 success, although the range was not quite as far, but CONSIDERABLY further than 500 feet (120m). Our flight experiments will continue in the spring. -Pat N8PK on 2/2/2010.
Make that a “well-matched” resonant antenna. I think most folks who attempt using the 10 mW transmitter fail to transfer all the precious power to the antenna, not considering how severe the losses can be between the TX module and the antenna port (if used), the feedline (if used), and the antenna itself (a quarter-wave ground plane style works better for me than the Vee). Testing and verification is important too, but who wants to mess with such minute details like me? But I digress. Visit http://simsat.net if you wanna see the tip of my iceberg.