[ns] TwoRayGround propagation loss path

[Jose Aguiar Silva]

Hello all,
  I have a doubt related to TwoRayGround propagation loss path in
ns2. Could you help me?
  I suppose the packets are lost as the distance increases, for
example, with the radio range of 100 m,  when the distance between two
nodes are 90 m, 30% of the packets are dropped. Is it a expected
behavior? Is there some way to do that? I mean, the drop criterion
based on distance?
 How can I do this be behavior?

Thanks in advance.
Jose Aguiar