The Red Circle is the terrestrial coverage of the iridium satellite near you. You can "grab" the Man Icon and move to a different location. The Vector line is the nearest satellite to your location and is "most likely" your satellite link.
---- Active Iridium Block1 Satellite in Current Constellation
---- Inactive or Spare Iridium Block1 Satellite in Current Constellation
---- Iridium NEXT Satellite Constellation Launching in 2016