Ok, I took the FC40 out for a routine flight, but could not get any satellites. Seemed really weird since I've don't all the plug and foil mods. After rebooting and going to different areas, I would get a few then sometimes none. Took the bird apart and started troubleshooting GpS connections from GPS module to Flytrex plug to PMU to NAZA trying to eliminate the problem. In the end, I had the GPS module in my hand connected directly to NAZA and still no go... Was getting real frustrated. Checked the boards for similar issues and finally saw someone mention to check patch antenna and connect to assistance software to isolate between the two (GPS module vs GPS patch antenna). The module was online and antenna didn't show any signs of damage.... I was lost. Finally thinking its time to dump the FC40 and sell off the parts and actually open my P3 box (yes it's been sitting in a box for 2wks ).... Anyway, slept on it and allowed me time to digest the situation. That's when I started disconnecting mods (Flytrex, Boscam transmitter, etc).... Eureka! I had forgotten that I replaced theFPV transmitter with a new mushroom antenna last week, but had not flown it. Swapped it out and all is well again. The moral of the story - test each mod with a flight before doing another and don't wait to test else you may forget. I'm sure others have learned this lesson the hard way . Just thought I'd share.