My Freespeak II base has 2 splitters attached. Looking at the FSII base status leds on the front panel, the flashing status LEDs were on 6 to 9. The cause turned out to be the AC cord for the splitter power supply was just partially installed. Just touching it and it fell out. Once the AC cord was inserted fully, the flashing stopped and antennas worked correctly.
The FSII base station has a status area on its front panel  for the 10 antennas that can be connected to it. If an antenna LED is flashing this indicates a problem, where the basestation cannot communicate correctly with the antenna . Please check the following - CAT5 cabling , Base >splitter > antenna (ensure all cables are wired correctly, plugged fully home and are not exceeding recommended cable distances)- Splitter and antennas are powered correctly