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STRIKE FINDER
DIGITAL WEATHER AVOIDANCE
APPENDIX A
Troubleshooting
antennas
loop-type
Strike Finder has three
inside its sensor. Two are
to
sense
antenna. The sense
receive bearing signal data, and the third is a
antenna is omni-directional, and the phase of its output signal is compared
with that of the loops to determine if the strike was on one side of the aircraft
or the other. The basic principles are similar to those used in
Fixed-Loop
Automatic Direction Finder
(ADF) for bearing detection. Each antenna
outputs a signal which is sent to the display unit, where it is digitized and
processed for plotting. The loop antenna signals are defined as X and Y,
and the sense signal is defined as P.
Strike Finder is basically detecting a radio signal radiated from a vertical
electrical discharge (lightning strike), which may be hundreds of miles away.
When diagnosing interference problems, it is helpful to consider the fact that
a strike with a current of thousands of amperes, hundreds of miles away,
may look the same (electrically) as a small spark of minimal amperes a few
feet from the sensor. This could be produced by something as simple as
bad brushes on an alternator, or a loose wire. Therefore, the location and
condition of other electrical equipment and wiring, relative to the sensor,
will influence the success of any Strike Finder installation, in terms of
electrical interference.
Once the power is turned on, Strike Finder automatically carries out a self-
diagnostic test every minute. If a fault is detected, the appropriate error code
is displayed in the lower left corner of the display, and the test rate is
"walking
increased to once per second, (see Figure 41, p.52.) Also, the
dot"
disappears from the display. When a fault condition is annunciated in
this way, the display may continue to plot strikes, but the data may not be
trusted for safe storm avoidance. These are the error codes which may
appear : X0, X1, X2,Y0, Y1,Y2, Z, S, B, P.
To assist in diagnosis of fault conditions, the following interpretation of error
codes is provided. Reference to Interconnect Diagram 2000-019 in the Strike
Finder installation manual.
PILOT'S
GUIDE
51
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