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#Antenna Considerations: The following is compiled from Garmin install documents.

  1. GPS Antenna: a. GPS Antenna—Locate as far as possible from all COM antennas and all COM transceivers, ELT antennas, and DF antennas. The GPS antenna is less susceptible to harmonic interference if a 1.57542 GHz notch filter is installed on the COM transceiver antenna output. b. Locate the GDU as far as possible from all COM antennas 3 feet from any VHF COM Antenna 3 feet from antenna > 25 Watts of power at least 6 inches from other antennas (including GPS) c. two gps antennas should not be mounted in a straight line.
  2. COM Antenna: a. 6 feet from any DME or COM antennas, 4 feet from ADF sense antennas. b. As far as possible from ELT antennas. Never be less than 3 feet between COM. c. Recommended one antenna mounted on the bottom close to the front and the other on the top of the aircraft close to the tail.
  3. Transponder Antenna: a. Vertically attached to bottom of the aircraft. Not within three feet of ADF sense antenna or COM antenna. 6 feet away from DME antennas 3 feet of cable at least to GTX 45R

With that said, here’s the layout I came up with.

Fairly simple layout. One GPS for the GTN and one GPS for the G3X, mounted in the overhead console in the cabin top, 1 foot apart, on either side of the centerline. Two COM antennas, both COMANT E-Series, one bent whip and one straight, mounted top and bottom. I’ll mount the bent whip on the bottom of the aircraft in between the front seats in the tunnel. The top mount straight antenna will be mounted 4 feet from the rear GPS antenna in the tailcone. Transponder antenna, also COMANT E-Series, will be mounted on the bottom of the aircraft about 6 feet horizontal distance rearwards of the top mount COM antenna.

Finally, will aim to mount the ELT antenna under the fiberglass tailcone fairing horizontally. Never ending debate on this topic, but there’s no guarantee you’ll be upright when needing this antenna, and 406MGZ doesn’t really require vertical polarization anyways.

For NAV/ILS/VOR, Archer NAV antenna in the right wingtip most likely. Will need AN509 screws and Garmin recommends DOW 738 to seal the antennas, although I will most likely wait until after paint to apply the sealant as the silicone messes with paint.

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