I just bought two Xbee Pro (S3B) 900 HP 200K modules with RP-SMA connectors. For the time being I am just trying to communicate between the two Xbees without any antenna using X-CTU . However, they are unable to receive any data when I send it from the other Xbee. What can be the issue? I have checked the Channel Mask, Preamble ID and Network ID and none of them seems to be an issue. Are antennas necessary to communicate if there are connectors on the modules?
Thanks in advance.