Kenwood made a conversion kit for the TKR-720 and 820… converting them to 12.5khz narrowband operation. this kit was called the “Z-Kit”

Note: I don’t have the Z-Kit nor any individual parts that I can sell. I placed these pages on the site strictly for informational use.

You can limit the transmitters modulation to +/-2.5khz without installing the Z-Kit; but the repeater receiver will need the parts replaced (as mentioned in the instructions) to be true narrowband receive.