F.u.n.k.e. F10185, Installation & Operation Manual

Page: 36 / 81

FSG 90 System
3 Installation
30
FAV_D10024 December 2014
3.7 Post-installation Check
3.7.1 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.
This must be performed by an authorized aircraft electronics inspector.
Testing of antenna matching between the
FSG 90(X)
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 SWR 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 counterweight length/dimensions, poor contacts, or damaged or
unsuitable (no 50 Ohm) coaxial cable.
In order to optimize radio range, it is suggested to care for an SWR 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 range, especially in comparison with known, other radio range
results of another aircraft at the same position on the ground at a known airfield location,
or outside of the hangar or workshop.
3.7.2 Ground checks with engine running
It must be ensured that the aircraft's electrical DC system voltage at the
FSG 90(X)
input
terminals is within the tolerances permitted at 14 Vdc (or 28 V with DC converter).
Battery only supplied systems operate from 10 to 16.5 Vdc. Such testing requires normal
RPM rated at cruising speed.
This testing evaluates both, the audio / noise influence and the RF radio range, at least
from 10 to 30 km distance to the ground radio station. With cruising RPM, cabin noise
background content shall almost not exist. Instead, loud and clear communications shall
be achieved!
The microphone shall be in both Transmit and Intercom Mode placed right at the lips in
order to obtain maximum voice level at lowest cabin noise content. Speak loud and
clear. Verify proper microphone sensitivity setting during SET-UP adjustments prior to
the first flight/on ground.
If possible, verify the communications capability also on both the low and high end of the
VHF COM band.