DJI Phantom 1,2 and 3 all have screw on props that screw on and off with a countering threads. This is a big reason many Phantom owners don't balance their props. Trouble is , you see the effects in the quality of the video they produce.
Here's how to balance these propellers:
You will require a balancer with top rollers.
You require threaded balancing shaft.
Screw the propeller onto the shaft and see which end goes up. That's the end you need to add tape to. Conversely to need to sand the other end.
Once the propeller fails to sink on either side, you have balance. Rotate the propeller 180 degrees and see if it remains unbiased.
A biased hub will require sanding on the top where the propellers are not stable. Attaching weight to the opposite side is usually unsuccessful.
Notice the tape on this propeller is in three pieces. It is unusual to require this much tape.
What else can unbalanced props affect
Propellers out of balance can cause more than jello. Flight controllers misbehave and motors destroy their bearings, when propellers are out of balance.