Category Archives: GTS-800 TAS

Avionics GTS-800 TAS

Mounting GTS-800 TAS Antenna

7 Hours, Oct 5th. Diving into the Garmin GTS-800 Traffic Alert System. This is an active interrogation traffic system that will reach out to other transponder equipped systems to locate and gather telemetry data from them for display on the GTN-750 screen. Unlike many of the other traffic systems (Mode S) the GTS-800 will work in an environment where Mode S is not available. For instance on the ground and other remote locations not covered by Mode S. I feel that although this system is costly and heavy it is worth the safety investment when flying Class B and other heavy traffic situations.

I started to mount the GTS-800 TAS top antenna and quickly referred myself to the many install manuals that Garmin uses for the GTS-800 system. I also referred to Sean Strasbourg (SP) GTS-800 install for guidance on the top antenna ground plane that is required. Sean gave a great write up on his top antenna install and I did my best to copy it word for word. I basically attached a sheet of aluminum to the top of the cabin with rivets and epoxy. I then glassed over the aluminum and am in the process of blending it into the cabin top.

On the underside of the cabin I had to cut out an area so that I could attach the VERY expensive 90 degree coax connectors to the antenna. There are four cables running up to the antenna. Sadly I will need to cut the connectors off the end of the coax since I cannot properly route the coax as planned with the 90 degree connectors. I am a little upset that this is required but Stein wanted to test the system prior to sending it to me. Fair enough I guess. I purchased 4 new 90 degree connectors. This area is also getting epoxy add back to seal up the cabin and add back strength.

I moved on to mounting the bottom antenna. The Garmin manual states no more than a maximum of 8 feet horizontal distance is allow between the top antenna and the bottom. I am just at 7 feet difference because we will have the MotoPod belly pod going on and off the aircraft. I had to place the bottom antenna far enough back to be clear of the pod movements. The Garmin manual also states the vertical alignment should be centered for both antennas but the bottom is off by about 2 inches. This was because of the structural support near the where the autopilot is mounted too and the fact this is where the elevator push rod is connecting to the rear most elevator push tube connects. I still need someone to help pound the rivets for the doubler plate for the bottom antenna. And I need to keep working on blending in the top cabin epoxy.