B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 192
Inflight Event / Encounter Other / Unknown
Flight Crew Took Evasive Action; Flight Crew Executed Go Around / Missed Approach
Environment - Non Weather Related; Aircraft
While on final to SNA (less than 5 miles from airport) and in the landing configuration we received a TCAS TA at our 12 o'clock and 300 FT below.  We quickly searched the area and could not see the intruder.  We opted to perform a go-around to avoid getting an RA in close and low. Upon return to the airport; I notified the Tower of the reason for the go-around.  He said that there was no observed traffic between us and the airport at the time of our go-around.  He said that other aircraft had also reported getting TA's on final (no times or dates given).  He referred to this as a 'phantom' TA or 'ghost' TA or something of the sort. I have never experienced the phenomenon of a 'ghost' TCAS signal at any other airport.  I wonder if there could be a TCAS signal being generated by something other than an aircraft somewhere close to the airport; perhaps by a tech company; test/manufacturing facility or drone.  If so; this should be corrected or made known to aircrews.  Apparently more than one aircraft has experienced this during a critical landing phase of flight in a high density traffic area.
B737-700 Captain experiences a TCAS TA on final approach to SNA and goes around. On the second approach; ATC advises that there was no traffic at the time of the go-around; but other aircraft have reported phantom TA's in the same location.