Honeywell KA 54 User Manual
Page 47
N
KRA 405B RADAR ALTIMETER INSTALLATION MANUAL
Page 2-21
006-10536-0010 Rev. 10
Oct/2005
(3) Test Procedure
a.
Connect the test equipment as shown in
, replacing the antennas in the
installation.
b.
Adjust the variable attenuator to 0 dBm (this setting
yields approximately 65 dBm loop loss). The KNI 415/
416 should indicate 900 to 1100 feet.
c.
Slowly increase the variable attenuator until the KNI
415/416 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 + Attenuation in Delayline +
Variable Attenuation).
d.
Pointer movement while adjusting the variable attenua-
tor in Step c. indicates a possible problem in the an-
tenna coax.
Connect the test equipment directly to the R/T trans-
mitter port and connect to the receiver port via the 6
foot test cable.
Try Step c. again. Pointer movement while adjusting the
variable attenuator indicates a possible R/T problem.
The R/T should be bench tested to insure proper opera-
tion.
e.
When Step c. 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
d. The pointer should stow at an attenuation of 110 dB
minimum
(40 dB + Attenuation in Delayline + Variable Attenua-
tion).
f.
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
.20 dB, therefore, length greater than 34 feet may im-
pair system performance).