APRS switch makes any Ham radio transceiver act like a APRS tracker

The following circuit uses a Tiny Tracker 2 APRS tracker from Bionics and a standard "Hockey puck" GPS receiver and allows switching between the speaker mic on a handy talkie and the APRS
tracker.

The switch has three positions as following:

Mic: has the transceiver in normal mode with speaker/mic fully functional and the APRS system does not transmit or broadcast GPS location to the APRS system.

APRS : has the transceiver in full APRS mode and GPS locations are broadcast to the APRS system
if any stations are within range. The transceiver  channel needs to be programmed for the APRS
frequency 144.800 Mhz as used in Europe.

Split: The transceiver RX is programmed for any number of your favorite repeater or simplex frequencies however the TX must be programmed for the 2m 144.800 as an output to the APRS system, So this will necessitate the programming extra bank of special split channels in your radio.
In this mode the tracker is running blind, as I live in a very quiet APRS area this is not a problem for me, however in a built up area with many APRS users this may be a problem, here is a circuit diagram 

and a photo for reference.