ka2zev
XTR Orphan Conversion
The TT3 install.
It has some mods in it.
SMT by pass caps on the power pins in and out.
Isolation diode on the back for output power (can not be back fed) when sharing a GPS puck with a second radio. (The long term goal is to make up dual band APRS units that share GPS data and diplex into one antenna.
The J6 system is used to turn the host radio on and off.
R9 is removed since we are using a logic input for carrier detect rather than the usual audio input. By loosing R9 we don't have a DC bias to deal with on the input to the PIC chip.
The 220k ohm resistor R5 is jumpered out.
This gives us more audio to work with the Midland radios.
10uF SMT cap under C2 (not sure, working from memory) on the bottom to give us a lower Z from the unit. Better drive into the relativly low impedance input of the Midland radio.
This with the other trimmer resistor gives us plenty of range to fully modulate the Midland radio.
XTR Orphan Conversion
The TT3 install.
It has some mods in it.
SMT by pass caps on the power pins in and out.
Isolation diode on the back for output power (can not be back fed) when sharing a GPS puck with a second radio. (The long term goal is to make up dual band APRS units that share GPS data and diplex into one antenna.
The J6 system is used to turn the host radio on and off.
R9 is removed since we are using a logic input for carrier detect rather than the usual audio input. By loosing R9 we don't have a DC bias to deal with on the input to the PIC chip.
The 220k ohm resistor R5 is jumpered out.
This gives us more audio to work with the Midland radios.
10uF SMT cap under C2 (not sure, working from memory) on the bottom to give us a lower Z from the unit. Better drive into the relativly low impedance input of the Midland radio.
This with the other trimmer resistor gives us plenty of range to fully modulate the Midland radio.