"PPP?  New one on me.  Is this not to be confused with PPK?  RTK and PPK (Real Time Kinematics and Post Processed Kinematics) GNSS are the ways to do that. For this application, PPK is often superior because real time position is not required, and…"

"Peter,
I have an 850mm quad with Pixhawk.  Two things come to mind.  One, I agree with Clifton.  "pilot's first mistake is trying to level the rotor disk before he takes off,  Because the airframe is still on the ground the gyro tries harder to…"

""I have found that the initial spin up of the motors is not usually consistent.  In other words all the motors don't have the same power level just before takeoff."
I agree.  Maiden flights, I select an open turf field and "jump start" take-off with…"

"Ok. I assumed the arrow is pointing forward. But we need to be sure its set for forward arrow in the config/tuning settings as it can be set for alternate directions in the settings. I fought with similar issues with two new Pixhawk (which both…"

"I'm reading two separate problems here. One, bad compass health from #1 external compass. Two, as you put it, "have yet to get good GPS". Does the "big" LED remain flashing blue? (Acquiring satellites). In config/tuning, is the setting for Pixhawk…"

"No dots? What happens if you uncheck #1 external compass and check #2 (internal) compass then run compass calibration?"

"I have to say.....although it should go without saying......put some distance between the "platform" and any metals, magnets and electronic devises.  I dont perform compass calibration indoors, anymore!!  And i live in upstate NY where its very cold…"

"I the past, with MP screaming errors at me, I found resolve by ignoring the the audibles and continue with repeating both calibration for compass and accelerometers.  "

"I'd start by un-checking compass #2 and compass #3 then repeat calibration."

"Ugh! Auto correct. That's Digi-Key"

"Might also try Digi-Key."

"I battled such a problem for a couple of months.  Turns out, it was due to vibration wreaking havoc with my Pixhawk accelerometers and/or gyros.  Two things I did to reduce vibration.  One, I replaced the cheap Gemfan CF props (1652).......even when…"

"If it's broken....fix it.  If it ain't broke......I'll soon fix that too.  Not my original quote, but thought I'd share ( :
Tony K, thanks for all your insightful suggestions.  I'm hoping I don't have to go back down that rabbit hole as I have found…"

""what firmware version are you running ? How cold is outside and how far is the buzzer from the pixhawk. These are important questions to this issue."

I'd have to check to confirm.....but 3.3.3 sounds right. (If you want a definitive answer on this…"

""The strange thing is that the Mission Planner reports the calibration is successful".
Yes, that's right, and that's why I suggest ignoring the audibles and continue forward with working through the list of calibrations.  That's what I DIDN"T do for…"

"There are many things I'm going to assume you have checked out.  Such as keeping metal objects (and your cell phone) away from compass and the Pixhawk, along with location and orientation of the GPS/compass puck, double check you have the…"