No … doesn’t work: Perhaps the antenna is the problem

I just coded a small python script that reads the received message from a TCP socket and starts to interpret them:

Message from socket:  181071E8FFFFFF3150020200FD 232 -86dBm
0x18 devId1: 1071E8 devId2: FFFFFF command: 3150
Message from socket:  181071E8FFFFFF23090302083415 231 -86dBm
0x18 devId1: 1071E8 devId2: FFFFFF command: 2309
Message from socket:  181071E81071E830C903000942CF 232 -86dBm
0x18 devId1: 1071E8 devId2: 1071E8 command: 30C9
Message from socket:  16FFFFFF921F0903000BE045 224 -90dBm
0x16 devId: FFFFFF command: 1F09

Strange is, that it only receives messages from the (one) HR80 radiator controller (Device ID 1071E8) closest to the receiver. And even for this one, the Received Signal Strength Indicator (RSSI) only is at -89dBm, which is very very low. For this reason, I think the antenna is not appropriate for receiving in the 868 MHz band, like other people already posted in comments.