AC1 Antenna Coupler

The AC1 general transponder antenna coupler provides 3 main functions. First it covers the antenna thus majorly reducing the propagation of the transponder signal. The AC1 provides > 20db of attenuation with >40db routinely seen on metal aircraft. The attenuation reduces or eliminates inadvertant interference to other aircraft or air trafic control. Secondly, it protects the aircraft transponder output electronics. The AC1 provides >8db of return loss, thus giving a safe 50 ohm match to the aircraft. Thirdly, an attenuated transponder signal is provided to the ramp tester. By coupling directly from the aircraft antenna, multi-path complications are avoided.

The AC1 was designed to work with most current shark fin and open 1/4 wave antennas. The exact opening dimensions are provided in the specs shown below. Mechanical clamping to both types of antennas is provided for bottom mount aircraft antennas. The unit comes with a coax cable and an additional attenuator. A further benefit of using the AC1 coupler is that it improves FAR part 43 testing. By removing multi-path problems, a solid repeatable connection is assured - unlike over the air testing.