After a looooooong stand by and quite a lot of miles by plane, car and train, I’m back to work.
Some minor modifications have been made to the filter mobo (larger and adapted strip line at the input and output).
The mobo has heavily been redesigned : for a better ground plane and better coupling, pass-through relays have been replaced with gull wing components. This way, a unique 2,9 mm HF bus (50 ohms strip line) goes from relay to relay. RF flow on the upper surface has very limited accidents.The I2C command board will probably be redesigned within this week, to comply with Alex’s wishes (better integration, no address assignation by default).
A Minimelf Diode (4148) pad has been added close from each relay. But as most of the “form C dual circuit/dual pos” DIL relays are polarised; it won’t be necessary to add this component most of the time.
The central bus is far from perfect an will be optimized all along this week.
The 100 W++ filter mobo will probably have a different design : same command daughter board, same filter daughter boards, but 4 separated relay boards (pin to pin compatible with the command board) will concentrate the switching stage. Wiring between filters and relays will be made with Teflon coax cable. I’ve try to use the pcb design with higher power rated relays, but in vain.