Gps fix in loiter takes 10 minutes and sometime i get no sat

i’m a little bit confused about how gps fix for loiter works:

most of the times i’m able to takeoff in loiter after around 5 minutes of wait.
I’ve seen that the copter waits for the gps hdop to be low enough (how much?)

today it was a little bit cloudly (really few clouds in the sky)

after 3 minutes i had 7 satellites but i wasn’t able to arm the copter in loiter

after 10 minutes with 8 satellites i was able to arm the copter.

after the flight i had to stop to replace the batteries and then the apm rebooted and the gps fix started from the beginning:

this time i had 0 satellites, even if i waited 10 minutes.

i resetted the board and the number of satellites moves between 4 and 0.

I really don’t know what to try to understand the problem.
I supposed that the radio and video antennas were causing some problems to the copter, so i rotated 90° the radio receiver antenna(2,4GHz) and i unplugged the video transmitter antenna (1,2GHz) apparentely without any effect

moreover my nexus 5 obtained 12 satellites after less than 30 seconds.

this is a picture of my setup, did i some errors in the setup?


note: my gps is ublox lea (i read on internet it is the best)

note that on the previous post, between 3 minutes and 7 minutes the lat and long coordinates was changing by 0,01", so i think that the error it’s less than 1 meter and the gps had low hdop (or at least not enough to arm).

dead forum?

dead forum?[/quote]

I had the gps antenna cable broken.
i resoldered it.

anyway the time needed to have a gps lock is too much high.
i increased the value of GPS_HDOP_GOOD to 250 in order to speedup a little bit the arming.

I also read that i should distantiate the gps from the rest of the electronic of about 10cm but up to now i should rethink the mechanic and i will try to avoid it.