Recently I purchased a refurbished Mini2. As it happens, soon thereafter I found a better deal on a brand new unit and bought it with an intention to return the refurb. However, i noticed that the new Mavic has a considerably worse range, both in control and video channels. I flew them in sequence on the same route in the direct line of sight, and the new one starts to have problems after 1km. The refurb has a strong signal at 1.3km unless I descend below the line of sight. I haven't attempted to fly beyond 1.3km, but I'm sure it could do another few hundred meters. What can cause this difference? The modern manufacturing is usually pretty consistent.