B KRA 405
Rev 6, June 2003 IM 006-00104-0006.dwd Page 2-11
2.5.3.1.B Required Equipment
The items listed below, or their electrical equivalent, may be used to conduct the tests
in this section.
2.5.3.1.C Test Procedure
2.5.3.1.C.1 Connect the test equipment as shown in Figure 2-12, replacing the anten-
nas in the installation.
2.5.3.1.C.2 Adjust the variable attenuator to 0 dBm (this setting yields approximately 65
dB loop loss). The KNI 415, KNI 416 should indicate 900 to 1100 feet.
2.5.3.1.C.3 Slowly increase the variable attenuator until the KNI 415, KNI 416 pointer
goes clockwise behind the mask. During this operation, the pointer should
continue to indicate the previous altitude +/- 10 feet. After the pointer stows,
the total attenuation in the line should be 102 dB minimum (40 dB + atten. in
delay line + variable atten.).
2.5.3.1.C.4 Pointer movement while adjusting the variable attenuator in step 3 indicates
a possible problem in the antenna coax. Connect the test equipment directly
to the R/T transmitter port and connect to the receiver port via the 6 foot test
cable. Try step 3 again. Pointer movement while adjusting the variable atten-
uator indicates a possible R/T problem. The R/T should be bench tested to
insure proper operation.
2.5.3.1.C.5 When step 3 attenuates a level of less than 102 dB to unlock the system,
this can be an indication of possible low TX power output. Reconnect the
equipment as in step 4. The pointer should stow at an attenuation of 110 dB
minimum (40 dB + atten. in delay line + variable atten.). Should the unit now
exhibit proper operation, check the antenna cables for total length greater
than 34 feet (remember, RG 393/U attenuation per foot at 4.3 GHz is 0.20 dB,
therefore, length greater than 34 feet may hurt system performance).
TABLE 2-4 RF Output Test Equipment (Delay Line)
QTY TYPE CHARACTERISTICS REPRESENTATIVE MODELS
1 Delay Line 1000 ft. Teledyne M7421B
1 Attenuator, Variable 0-40 dB, 4-8 GHz. Narda 794-FM
2 Attenuator, Fixed 20 dB, 3-6 GHz. Narda 773-20
2 Adapter N
F
to SMA P/N 030-00123-0000,
Americon 2082-2300.
2 Adapter N
M
to TNC
F
Amphenol 78800
1 Adapter N
M
to TNC
M
Amphenol 78875
1 RG393/U cable with TNC
M
Connectors.
6 ft. P/N 024-00075-0000,
mil spec M17/127-RG393
RELEASED FOR THE EXCLUSIVE USE BY: AIRCRAFT ELECTRONICS ASSOCIATION
UP536434
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