Garmin GTN 6 series Maintenance Manual page 101

7.1.2.2 Signal Acquisition Check
NOTE
All other avionics should be turned off at the start of this test, with the GTN powered on in
normal mode. After reinstallation, the initial acquisition of position can take up to 20
minutes. Subsequent acquisitions will not take as long.
NOTE
For best results, this check should be performed outdoors away from large buildings or
objects that could obstruct the GPS antenna.
Ensure the GTN is able to acquire sufficient satellites to compute a GPS position. From the Home page,
touch the System key and then touch the GPS Status key. Under "GPS Solution", ensure that a 3D Fix or
3D Diff Fix is obtained. If the unit is unable to acquire satellites, move the aircraft away from obstructions
which might be shading GPS reception. If the GPS solution does not improve, check the GPS antenna
installation.
Once GPS position information is available, verify that the LAT/LON agree with a known reference
position.
7.1.2.3 Receiver/Transmitter Operation (GTN 635/650/750 Only)
Tune the unit to a local VHF frequency and verify the receiver output produces a clear and understandable
audio output. Verify the transmitter functions properly by contacting another station and getting a report of
reliable communications.
190-01007-A1
Rev. 6
System Maintenance Manual GTN 6XX/7XX Part 23 AML STC
Page 7-5