YAY Polar
There must someone have too much money (Or a proper use for it...)
Can I ask you for some assistance when it comes to Devboard Rev2 ?
PCB is FR4 1.6mm , Er = whatever dirty pcb delivers....
Feed to the Filter Network is 30mil , Clearance 7mils (Thats what I got for 50ish Ohms with an Er of 4.5 )
After the Filter the Feedline to the Antenna and SMA is 10mils , probably slightly off 50Ohms -> 87Ohms....
Regarding ESD protection : Definitely in Rev2
I thought about GPIO0 a while and even had it in the layout but removed it in the end. I would need a real open drain pin to pull the GPIO down, otherwise one could only use the board when the ftdi rts pin is correctly driven. Also when the ftdi is connected directly the GPIO wouldn't be really usefull. In the end I couldn't are myself to come up with something proper... But again Rev2 ?
Dirt cheap PCBs is so cheap that an other try doesn't really hurt the wallet.