.
Figure 3-1 Cable phasing measurement set-up.
3.2.2
CSB/SBO phasing
127(
6ZLWFKRIIWKHFOHDUDQFHWUDQVPLWWHU
$VFHUWDLQWKDWWKH7[PRGXODWRUXVHGLVRSWLPDOO\FDOLEUDWHG
Connect the NM3710 Field Test Set to the monitor BNC test connector in the ADU. (Use
20..30 dB attenuator at the I/P of the Field Test Set.)
Adjust Course SBO phaser in the Cabinet (associated with Tx to air) to obtain 0.0% DDM
reading.
Repeat the phasing procedure for the other transmitter.
Switch off the course transmitter.
With the clearance transmitter on repeat the phasing procedure now adjusting the clearance
SBO phaser associated with Tx to air.
3.2.3
Antenna cable lengths (Electrical phase equality)
Each antenna cable should be electrically checked before the end connector is terminated in
the LPDA.
Utilise a vector voltmeter or network analyser. Establish antenna cable (A1) (leftmost seen
from rear) return phase as 0° reference phase.
Measure return phase for each of the remaining antenna cables (A2...A12).
Tolerance: ±1.0° true electrical cable length.
See measurement set-up diagram Figure 3-1.
20dB
A
B
VECTOR
From cabinet
CSB BNC o/p
CABLE UNDER TEST
OPEN END
DIR. COUPL.
Summary of Contents for NM 7000 Series
Page 7: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 11: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 Figure 2 3 ...
Page 13: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 19: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 21: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 23: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 25: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 27: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 31: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 45: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 55: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 65: ... ...
Page 81: ... ...
Page 111: ... ...
Page 129: ... ...
Page 132: ... ...
Page 134: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 150: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...
Page 158: ...1250 5 167580 17 1 1 6 67 0 167 7 21 200 66 21 1 1 22 1DYLD YLDWLRQ 6 ...