Hello, With the frequency conversion kit MC-509, working on 1.8 MHz is possible for the BC-610. The modification of Radio-Transmitter BC-610 is unsolder one end of resistor R9. Unsolder and resolder at each frequency change is very difficult. Has anyone knowledge it is possible to make this resistor "plug-in-unit" ? Many thanks for help. Also I'm needing the TU-61. 73. Henri-Paul F6FED