can't get more then 400 meter rabge between "XBP9B-DMST-002" modules with "A09-HASM-7" 2.1 dBi Antenna in two devices. after 400 meters RSSI drop and loss connectivity.
previously, i am using same modules with same configuration that modules are working up to 700 to 800 meters (LOC range) distance.
only difference in these modules are ,
Previously i have bough these modules kits from www.EBAY.com they have provided antennas (no any gain information available) with XBEE modules. ebay did not share the Antenna part number. only moudles part number shared.
(Web Link; http://www.ebay.com/itm/Xbee-PRO-S3B-900HP-RPSMA-Wireless-Kit-250mW-28-miles-/321148558576)
Currently i was bought these modules and antennas from www.digikey.com.
(module PN "XBP9B-DMST-002" and Antenna PN "A09-HASM-7")
kindly confirm what is the possible reason which is causing reduced the successful communication distance from 800 meters to 400 meters.
Hardware Design Engineer