TECHNISONIC INDUSTRIES LIMITED
TDFM-9300 Installation Instructions
TiL 13RE471 Rev. D Issue 5
28
D.
The following procedure checks for second harmonic interference to the glide slope
receiver from the TDFM-9300. All transceivers produce harmonics (multiples of the
wanted frequency) and while the TDFM-9300 far exceeds FCC requirements,
interference can still be experienced depending upon antenna position and separation.
Furthermore, other equipment in the aircraft and the structure of the aircraft can
generate harmonics where dissimilar metals make contact or where grounds are
isolated, etc. This is also true of aircraft hangars; therefore, testing should be done
outside away from any structures where possible.
With a portable glide slope generator, provide enough signal to firmly activate the
indicator needle and hide all flags. Increase the signal level by 3 dB. Modulate the
TDFM-9300 transmitter on the following frequencies for at least 20 seconds. Observe
the Glide Slope displays. Look for any movement of flags or needles on the navigation
display. If an interference condition is detected, then the installation will have to be flight
tested according to the following procedure. Using the table below, determine the glide
slope frequency based on the localizer frequency of the ILS to be used. Divide the glide
slope frequency by 2 and program into the TDFM-9300. Fly the aircraft to intercept the
localizer and glide slope (both needles centered) at 26 nm from the runway. Transmit on
the TDFM-9300 for 10 seconds and watch for any deflections or flags. Repeat the test
every 2 nm until the indicators are not affected. If the distance is greater than 18 nm,
then a pass shall be recorded. Otherwise the TDFM-9300 shall be placarded “Do not
transmit while on ILS approach.”
Localizer
Glide Slope
Localizer
Glide Slope
108.10
334.70
110.10
334.40
108.15
334.55
110.15
334.25
108.30
334.10
110.30
335.00
108.35
333.95
110.35
334.85
108.50
329.90
110.50
329.60
108.55
329.75
110.55
329.45
108.70
330.50
110.70
330.20
108.75
330.35
110.75
330.05
108.90
329.30
110.90
330.80
108.95
329.15
110.95
330.65
109.10
331.40
111.10
331.70
109.15
331.25
111.15
331.55
109.30
332.00
111.30
332.30
109.35
331.85
111.35
332.15
109.50
332.60
111.50
332.90
109.55
332.35
111.55
332.75
109.70
333.20
111.70
333.50
109.75
333.05
111.75
333.35
109.90
333.80
111.90
331.10
109.95
333.65
111.95
330.95
Summary of Contents for TDFM-9300
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