User's Manual

TECHNISONIC INDUSTRIES LIMITED
www.til.ca
TFM-550 Installation & Operating Instructions TiL 99RE262 Rev A Issue 8
A-7
D. The following procedure checks for second harmonic interference to the glide slope receiver from
the TFM-550. All transceivers produce harmonics (multiples of the wanted frequency) and while
the TFM-550 far exceeds FCC requirements, interference can still be experienced depending
upon antenna position and separation. Furthermore, harmonics can be generated by other
equipment in the aircraft and the structure of the aircraft where dissimilar metals make contact or
where grounds are isolated, etc. This is also true of aircraft hangers, 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 TFM-550 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 TFM-550. Fly the aircraft to
intercept the localizer and glide slope (both needles centered) at 26 nm from the runway.
Transmit on the TFM-550 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 TFM-550 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
FREQUENCIES RESULTS
VOR/ILS #1 TFM-550 PASS FAIL