Steval-FKI433V2 & SDK_Chat example: how to increase a Communication range?

[bvn123]

I use SDK_Chat example (S2LP DK1.2.1\..\S2LPLibrary_Examples) as a base for my project.

To increase a Communication range I change next parameters:

DATARATE                   38400 (default) to 4800

POWER_DBM                  12 (default) to 14

RSSI Threshold SRssiInit *x->cRssiThreshdBm -106 to -130

Question:

Are there another parameters, which may be changed in SDK_Chat example to increase the Communication range?