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Old Aug 29, 2015, 06:55 PM
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Something I always wondered did become quite relevant today during a flight:

Is it normal that it takes the 350QX1 V2 (I guess that's still the correct term for QXs bought in spring 2014?) much longer to remain steady on a GPS hold position in Stability/AP mode? In Green Mode, position has always been rock stable for me. In Blue and Purple however, there was always some drifting until it remained in one position (without stick input). Is that normal?

Today that drifting got really bad, almost lost the quad (maybe GPS was even lost completely, had waited 15mins for the lock before that flight). And since that's not the only strange thing happening, I guess I'd better retire it for safety reasons...
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Old Aug 29, 2015, 09:48 PM
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GPS issues, were you out in the clear away from trees and buildings? Was the sky clear or heavy overcast?

The drifting can indicate your accelerometer calibration is due. Videos on the HH site on how to do it. Or here from the V2 manual My website 4Props.ddns.net
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Old Aug 29, 2015, 11:24 PM
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Sky was almost completely clear, and the field was the same I had been flying over for many times last year. Only this year I started to get problems with GPS fix taking very, very long - and only there. In other locations it never took that long, not even this year. There is no real explanation, it's a rural area with no reason for interference I could think of. I even paid attention to KP index.

Thanks for the hint with accelerometer calibration, but if that was the reason, wouldn't the QX be drifting in Smart Mode as well?

In fact I suspected accelerometer problems already last year when I had some strange flips out of nowhere. And in fact today this happened as well when I finally switched to Smart Mode and thought I was in the clear! But: After that had happened last year (resulting in a crash) I send the QX to Horizon to check, and it came back with "no problems found". So I believed them.

I imagine if the accelerometer was extremely off, wouldn't the QX be acting strange (like flipping) all the time and not once in maybe 2 hours of accumulated flying time?

Thanks!
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Old Yesterday, 08:26 AM
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The system will correct the drift in Smart mode as position hold is in play. I sent my QX into HH once with a broken motor mount and they said it was fine. Go figure!

Sorry, your GPS has me stumped.
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Old Yesterday, 12:07 PM
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Quote:
Originally Posted by 747TestPilot View Post
Sky was almost completely clear, and the field was the same I had been flying over for many times last year. Only this year I started to get problems with GPS fix taking very, very long - and only there. In other locations it never took that long, not even this year. There is no real explanation, it's a rural area with no reason for interference I could think of. I even paid attention to KP index.
...

Thanks!
It's possible that someone is using a GPS jamming device in the area.

If you have another GPS device that shows the reception and signal strength of satellites take it for an investigation foray around the area.

if that's the problem you could always fly without using GPS.

Investigate GPS signal jamming. There's plenty if information available. By the way, jammers are illegal.
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Old Yesterday, 08:10 PM
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747TestPilot,

15 min to bind is telling you that something is very wrong. Lock relies on everything working correctly. 4-Props was correct to suggest an accelerometer calibration, but other things will prevent calibration that are not even part of your quad. For instance, my 350 began to take a long time to achieve lock when one of the sticks in my DX8 was going bad. The quad saw that problem as the sticks not being in their initialization positions, so it would not lock. When I bound to another transmitter, it locked in its usual 35 sec. Another example was flying a Mobius camera. I knew the camera could cause trouble, and when I mounted it, I could not get GPS lock in under 2 min, so I began shielding parts of the camera with copper foil until my lock times returned to 35 sec. Midnite's suggestion to check for GPS interference is another good thing to check that is also exterior to your 350.

As for internal problems, have you experienced a bad crash before your 350 began to act up? Is there a chance there is a loose wire? a pinched wire? an antenna out of position? Taking a look inside is a way to spot problems of this type.
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