After I tried to fit all the components like Bandpass filters and Power Amplifiers on the mainboard PCB and i find out that they dont fit as whole on a 10x10cm PCB (this size is obtainable very cheap in China), i decided to put the filters and PA on a seperate PCB, which is connected to the Mainboard via a coax cable (for the HF signals) and a ribbon cable for the digital signals and power supply...

A benefit of putting the PA on a seperate PCB is, that the high power HF signals are kept away from the sensitive HF mixers on the Mainboard, which should help to minimize intermodulation products...

I've put the schematics for all PCBs on in the files section.