newbuild tarot 650 looking for some advise..

[Vc1]

Hello everyone im vass.
I have built a tarot ironman 650, tmotor 700kv motors, 13×4 props 40a escs, naza v2 fc, 5000mah 3s 45c lipo... futaba t8j. I have had my first 4 flights all rrasonably sucessfull however cannot seem to get a solid hover in gpsatti mode ?? Iv adjusted the gains but found no major improovment... all calibrations have been carried out.. when i yaw altitude drops or rises, and becomes a bit wobbly, altitude hold in general is not the best some times climbing on its own, roll is kind of ok but after repetition of the exorcise becomes scarily unstable, im slowly getting there but and advise would be great !!
My main point is gps hold mode dosent seem to be holding a locked hover more like within 5-10 meters of the hover point??

 

[jinly]

I assume you did the advanced calibration (i.e. With the craft perfectly level). Did you get at least 6 gps satellites? Are you using the default PID's? Did you check for magnetic declination?Just some suggestions

 

[Old Man]

Assuming you have a good FC and GPS brand and unit, review the location of the GPS to motor, battery, and ESC wiring. A common error is routing power transmission and signal wires close to a GPS unit, or the GPS wiring. Look at that and see if something in that line up might be improved. Altitude hold modes that don't use GPS will not be affected by a weak GPS or lack of it. However, an under powered or a copter with the wrong size propellers will act as you describe and be essentially "un-tunable". If your motors and ESC's will handle it, try a 4s battery and see if that doesn't change how it responds.

You live in a place I would very much like to see someday. So much history.