After not having used my old (very, very old...) transverter, it was time for a modern update. I was attracted to the SG_Labs transverters build by LZ5HP. The specifications are to be found in the internet, it uses 432MHz for IF and produces well over 2.5W at 2300 - 2400MHz. My version is the latest update in regard to the final stage, it looks definitely different compared to the versions with the smaller final FET. I also tested sensitivity and freuqncy_accuracy, I was surpriced!
My transverter was exactly on the correct frequency even without the external 10MHz connected. Within 100Hz at 2320,2MHz, amazing!

Default this transverter is delivered with 4 pre-programmed LO-frequencies. The selection which combination of RX/TX frequencies is used, is done by selecting the correct jumpers inside the transverter_housing. This of coarse is not very convenient, that is why I added a 4-position rotary_switch.
Because the jumper_selection is based on binairy counting (00, 01, 10 and 11), it needed a little thinking to do it the most simple way. I used 4 skottky diodes and 2 resistors in combination to a 4-position rotary switch. The connection of the circuit is towards the I/O pins of the uP inside the transverter, where normally the jumpers are. Measure which side of the pinheader this is, the opposite side is the GND of the jumper, which obviously is then not to be used. The 3V3 power is also availble from the jumper inside the transverter (for re-programming the LO-frequency):

VK3FS amongst others describes how to re-program the internal LO-frquencies of the 4 memory location to your own needs
All it needs is a USB to TTL (0 / 3,3V) converter and connect the TX and RX of this cable to the serial jumper pins inside the transverter. Make sure this USB/TTL converter is NOT +/- 12V, as this will not be tolerated by the processor in the transverter!
The link to the video how to make the change in LO is found here: Reprogramming LO