Technical data

VHF/AM RADIO FSG 2T
4 Recommended Set-up Sequence
June 2014 FAV_D10048 49
4.7 Testing on the Ground with engine Off
Verification after installation completion.
After installing the unit, check all aircraft control movements to be sure no electrical
cable interfere with their operation. All aircraft and radio functions shall be tested after
installation completion to identify, whether malfunctions caused by mechanical and / or
electrical installation work occurs. Remove all foreign parts.
This verification must be performed by an authorized Aircraft Electronics Inspector.
Testing of antenna matching between the FSG 2T antenna socket (BNC) and the BNC
antenna cable connector is required, using a suitable 50 Ohm VHF Reflectometer
(VSWR meter), or a directional Wattmeter.
The VSWR must be less than 3:1 over the full frequency range, tested at least in 1 MHz
steps (reflected power shall be less than 25% of the forward RF power output). If this
limit is exceeded, this indicates a mismatched antenna and may be caused by wrong
antenna radiator or counter weight length / dimensions, poor contacts, or damaged or
unsuitable (other than 50 Ohm) coaxial cable.
In order to optimize radio range, it is suggested to care for a VSWR of less than 2:1
(reflected power shall be less than 11% of the forward RF power output).
IMPORTANT!
 If the antenna is belly mounted, perform antenna matching measurements if
possible in flight, or at least while the fuselage is lifted upwards, using
wood / non metallic supporting material. This avoids antenna mismatch
caused from ground proximity.
Using known, but distant located fixed stations (VOLMET, ATIS) will also help in
determining the radio receiving range, especially in comparison with known radio range
results of another aircraft at the same position on the ground at a known airfield location,
outside of the hangar, trailer or workshop.