Garmin GSR 56 Installation Manual - Page 19

3.3.3 Iridium Antenna Location As with any antenna installation, keep the following points in mind: 1. The Iridium Satellite signal is a line-of-sight signal. Locating antennas too close to obstructions such as the vertical stabilizer will limit the reception of the satellite signal. 2. Maintain about three feet from heater, ignition, autopilot, and other control surface actuators and motors. Maintain about five feet from fluorescent lamps, related ballast, air conditioners, blowers, strobe lights and power supplies. 3. The minimum distances to be observed when selecting an antenna location are as follows: • 30 inches from any passive (receive only) antenna such as GPS. • 5 inches from a VHF active antenna such as COM or ACARS. • 5 inches from an active radar altimeter (4 GHz). • 30 inches from a UHF / Microwave transmitting antenna such as a transponder, DME, active TCAS, UAT, SATCOM, or Flitephone. • 34 inches between the Iridium Antenna for dual or multiple Iridium GSR 56 installations. 4. The Iridium antenna must be mounted on top of the aircraft for greatest satellite visibility (Figure 3-1). For best performance, select a location with an unobstructed view of the sky above the aircraft when in level flight. Location of communication antennas too close to the Iridium antenna may not only degrade the transmission through reflection, but can also absorb and re-radiate the transmission causing a condition similar to having two COM antennas located in close proximity to each other. Figure 3-1. Antenna Installation Location GSR 56 Installation Manual 190-00836-00 Page 3-3 Revision F