GIA 63 Installation Manual Page 2-9190-00303-05 Revision T2.2.7 VHF COM/GPS InterferenceOn some installation VHF COM transceivers, Emergency Locator Transmitter (ELT) antennas, andDirection Finder (DF) receiver antennas can re-radiate through the GPS antenna. The GIA 63(X) COMdoes not interfere with its own GPS section. However, placement of the GA 56 GPS antenna (or othercomparable antenna) relative to a COM transceiver and COM antenna (including the GIA 63(X) COMantenna), ELT antenna, and DF receiver antenna is critical.Use the following guidelines, in addition to others in this document, when locating the GIA 63(X) and itsantennas.• GPS Antenna—Locate as far as possible from all COM antennas and all COM transceivers(including the GIA 63(X) COM), ELT antennas, and DF antennas. The GPS antenna is lesssusceptible to harmonic interference if a 1.57542 GHz notch filter is installed on the COMtransceiver antenna output.• Locate the GIA 63(X) as far as possible from all COM antennas.If a COM antenna is found to be the problem, a 1.57542 GHz notch filter (Garmin P/N 330-00067-00)may be installed in the VHF COM coax, as close to the COM as possible. This filter is not required forthe GIA 63(X) transmitter.If a COM is found to be radiating, the following can be done:1. Replace or clean the VHF COM rack connector to ensure good coax ground.2. Place grounding straps between the GIA 63(X) unit, VHF COM and a good ground.3. Shield the VHF COM wiring harness.2.3 Rack ConsiderationsA location away from heating vents or other sources of heat generation is optimal. The GIA 63(W) canbe mounted using the G1000 system rack. The unit may be mounted remotely if desired. The GIA 63Hmust be mounted in the Helicopter Rack.DRAFT Rev T 11/12/2010