TECHNISONIC INDUSTRIES LIMITED
TDFM-9200 Installation Instructions
TiL 13RE472 Rev. B
2-20
D.
The following procedure checks for second harmonic interference to the glide slope
receiver from the TDFM-9200. All transceivers produce harmonics (multiples of the
wanted frequency) and while the TDFM-9200 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-
9200 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-9200. Fly the aircraft to intercept the localizer
and glide slope (both needles centered) at 26 nm from the runway. Transmit on the
TDFM-9200 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-9200 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
