[appendix] == TeleGPS System Operation === GFSK Telemetry TeleGPS's native telemetry system doesn't use a 'normal packet radio' mode like APRS because it's not very efficient. The GFSK modulation we use is FSK with the base-band pulses passed through a Gaussian filter before they go into the modulator to limit the transmitted bandwidth. When combined with forward error correction and interleaving, this allows us to have a very robust 19.2 kilobit data link with only 10-40 milliwatts of transmit power, a whip antenna in the rocket, and a hand-held Yagi on the ground. We've had flights to above 21k feet AGL with great reception, and calculations suggest we should be good to well over 40k feet AGL with a 5-element yagi on the ground with our 10mW units and over 100k feet AGL with the 40mW devices. :aprsdevices: TeleGPS :configure_section: _configure_device include::aprs-operation.adoc[] === Configurable Parameters Configuring TeleGPS is very simple; the few configurable parameters can all be set using the TeleGPS application over USB. Check out <<_configure_device>>.