Installation Instructions

GTN 6XX/7XX AML STC Installation Manual 190-01007-A3
Page 3-4 Rev. 4
If a VHF COM transmitter causes problems with the GPS on the selected frequencies as listed in the post-
installation checkout, the problem may be due to the ELT. This can be verified by disconnecting the ELT
antenna coaxial at the ELT unit. If the ELT is found to cause the problem, then contact the ELT
manufacturer or replace the ELT.
3.3.1.1 GPS/WAAS Antenna Cable Installation for IFR-Certified Non-Metal Aircraft
The GPS/WAAS antenna cable for non-metal aircraft must be overbraided to protect against lightning
currents being injected into the antenna port during a lightning strike to the aircraft. Aircraft constructed
of metal tube and fabric that have the antenna grounded to the metal tubes do not require this overbraid.
See Appendix G for a list of aircraft requiring this overbraid. Both GPS/WAAS antenna cables must be
overbraided in a dual GTN installation. Nonmetallic VFR-only aircraft do not need overbraid on the
GPS/WAAS antenna cable. Install the overbraid in accordance with the procedure below and measure the
length of cable needed to route it through the aircraft from the mounted antenna location to the GTN
backplate in the radio stack. Cut the cable to the measured length. The length of overbraid required will
be the length of the GPS/WAAS antenna cable plus 6 inches.
1. Slide the overbraid over the entire length of the GPS/WAAS antenna cable.
2. Route the GPS/WAAS antenna cable/connector assembly with overbraid from the GPS/WAAS
antenna to the GTN backplate in the radio stack per the instructions in Section 3.3.1.
3. Roll back approximately 1.5 inches of the overbraid end at the antenna end.
4. Leaving the rolled-back portion free, secure the outboard end of the overbraid around the
GPS/WAAS antenna connector with an electrical tie-down strap.
5. Fold the free overbraid ends back over the tie-down strap and secure them to the cable with two
additional tie-down straps.