Why DWM1000 2D short range

Hi,

We just installed 3 anchors 1tag of DWM1000-Dev and configured all with channel 2, 6.8MHz. Before that we have succeed in that one tag can read one 30 meters with 260 meters. However, when we use up to 2 anchors at the same time, tag can only read all the Anchors shorter than 30 meters. When the range is longer than 30 meters, the tag can only read anchor 0 but anchor 1 and anchor 2. So, there is no way to do 2D range if the range is longer than 30 meters.

We can not understand this? Help us.

we do not know why? The problem seems strange.