The SP - 1 offers the possibility to connect two receivers to one antenna, either passive or active. The very high degree of isolation between both receivers ensures that each receiver can be tuned and operated if it was connected to its own antenna, because there is no mutual interaction or signal loss when one receiver is tuned to a different frequency band than the other. The SP - 1 can also be used as combiner for two antennas on one receiver. This offers the possibility to combine the signals of for instance a horizontal- and a vertical antenna, antennas in different directions and so on. A dual antenna system can offer a much better performance than just a single antenna. Thanks to the high isolation of the SP - 1, both antennas don't "see" each other, preventing that the signal of one antenna is re-radiated by the other antenna. That is what happens if you simply connect both antennas in parallel.