Installation Accessories Required But Not Provided; Antenna Installation - Garmin 500 Series Installation Manual

3.4 INSTALLATION ACCESSORIES REQUIRED BUT NOT PROVIDED

The following installation accessories are required but not provided:
COM Antenna: (GNC 520 and GNS 530 Only) Shall meet TSO C37() and C38(). Broad band,
50 Ω, vertically polarized with coaxial cable
(GNS 530 Only) Shall meet TSO C40() and C36(). Broad band, 50 Ω,
VOR/LOC Antenna:
horizontally polarized with coaxial cable
(GNS 530 Only) Shall meet TSO C34(). Broad band, 50 Ω, horizontally polarized
Glideslope Antenna:
with coaxial cable or low-loss splitter used with the VOR/LOC antenna
(GNC 520 and GNS 530 Only) 500 Ω nominal impedance
Headphones:
Microphone: (GNC 520 and GNS 530 Only) Low impedance, carbon or dynamic, with
transistorized pre-amp

3.5 ANTENNA INSTALLATION

For the COM, VOR/LOC, and Glideslope antennas, follow the manufacturers' instructions.
The remainder of this section applies to the GPS antenna. The GA 56 antenna outline and footprint
dimensions are shown in Figure 3-2, page 3-5.
1. Using the backing plate as a template, mark the location of the mounting holes and the through
hole for coaxial cable. Drill or punch the holes.
2. The antenna installation must provide adequate support for the antenna considering a maximum
drag load of 5 lbs. For the GA 56 antennas (at subsonic speed). Install a doubler plate to
reinforce thin-skinned aircraft. Observe guidelines for acceptable installation practices as
outlined in AC 43.13-2A.
3. Seal the antenna and gasket to the fuselage using a good quality electrical grade sealant. Use
caution to insure that the antenna connector is not contaminated with sealant. Insure that the
mounting screws are fully tightened and that the antenna base is well seated against the gasket.
Do not use construction grade RTV sealant or sealants containing acetic acid. These sealants may damage
the electrical connections to the antenna. Use of these type sealants may void the antenna warranty.
500 SERIES INSTALLATION MANUAL
P/N 190-00181-02
CAUTION
Page 3-3
Page Rev. B