[time-nuts] Toy radiolocation and LORAN envelope
holrum at hotmail.com
Tue May 27 19:44:05 UTC 2014
I fly large model rockets and radio tracking beacons are very common in this application. Most are based upon wildlife/bird tracking products. Walston Retrevial Systems makes some very good systems. They run on button cells and can ping for a few days to weeks. Most operate around 220 Mhz. A handheld yagi attached to a receiver with a good gain control is used to localize the signal.
The schematic of one simple pinger transmitter is attached. It requires a bit of futzing with component values to get the circuit to ping. Transistor/crystal selection is important. I set mine up to run on a 3V cell instead of 1.5V I get about a 1 mile range in open conditions. Fancier versions add a buffered output stage.
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