GPS Radio Link Complete Details and Schematics

In this video I go over the miniaturized GPS radio NMEA Sentence FSK encoder, using a Garmin GPS 18x LVC, Mega 2560 Pro Mini, and MX614 modem IC. I also go over the matching FSK decoder used at the distant party's location.
With the Garmin's ability to limit which sentence is sent and it's high baud baud rate, it is possible to retransmit the $GPRMC sentence at 1200 baud in less than 1 second. This gives you the ability to send a new sentence at a rate of once per second.
Decoding software used at the PC end like Spectrum Lab, only needs a couple of good sentences to get a good decode. So the mobile user only needs to be keyed up for 3-4 seconds (depending on repeater or c2c) to get a successful transmission of coordinates to dispatch.
Last part of this project will be to get printed circuit boards made using KiCAD.
Total Price per Mobile -------- Less than $125 (depending on quality of case)
Total Price per Base ------- $40