What should we do to improve Xbee PRO 900HP outdoor range?

We bought recently two Xbee-PRO 900HP (9B-DMST-002) as we need to implement a Mesh network around a big park. The datasheet of this device indicates that it can transfer data up to 6.5km with a 2.1 dipole antenna. However, after two different tests, we could transfer data between the modules when its distance was lower at least 400m, so there may be something wrong.
During tests, the configurations of both devices where:

  1. Power Supply: 3.3V – 2A
  2. Antenna: 2.1dB
  3. PL: 4 – Max
  4. RF Data Rate: 200Kbps
  5. Baud rate: 9600
  6. Mode: API
  7. Environment: No obstacles.
  8. Antennas high: 3m from floor.
  9. Pins connected: 1, 2, 3 and 10.
    Is there anything that we are not considering? How do you measure the maximum distance?
    Thanks for your help :slight_smile:

At the current antenna height you have, you are not going to get very far. In order to go farther, you have to increase the height of your antennas.

See http://knowledge.digi.com/articles/Knowledge_Base_Article/Maximizing-range/?q=maximizing+range&l=en_US&fs=Search&pn=1 for a better understanding of what I am referring to.