15 December 2021

Trying again on 24 GHz

Two years ago I briefly tried to use 24 GHz radar modules (CDM-324) for HAM operations. Back then I considered them not suitable, also considering that I discovered they lacked the RF sponge inside the lid.

Last week at a flea market I could buy the RF sponge, so it is worth trying again.

Now there is a sponge in the lid.

I built two circuits with a 78L05 and proper DC filtering. I could get two modules at about 70 MHz apart and the frequency is quite stable (in a constant temperature room). The good news is that the hand-effect is negligible and there is no modulation.

Next step is to add modulation.

BTW, I have lots of sponge in small rectangles in case someone needs it.

BTW2, would the sponge have some effect on HB100 too?!