Very recently I caught sight of a Bosch KF-166 VHF transmitter which has been modified to operate on 144.800 MHz, the APRS frequency in Ebay. The device itself has two channels and a selective call facility -- which has been disabled. It is a PCB board which has been taken out. The KF-166 also works without, given that we are going to run 1k2 packet radio over it. The quartzes have been replaced by two 144.800 ones while only the first channel is installed. We don't need the second channel here. And I removed the microphone device and recycled the cord to go right into the TNC plug. A very neat and handy solution to serve as a transmitter for a APRS digi.
Here is how I am going to use it:
And here's some programming tips for the KF-166: http://db0sif.darc.de/cgi-bin/dpcmd?R%20TECHNIK%20620
Microphone plug pinouts:
A LED gelb B LED grün C Masse D + 5,5 Volt E Sendetaste F Frei G Mikrofon H Ruftaste J Frei K Lautsprecher L Löschtaste M Frei