User's Manual

2.1.4 Sencore MSM980
The Sencore MSM980 is a dedicated test device, which provides a number of tests and storage of
results related to the installation and troubleshooting of subscriber units. One of its basic modes is
to display in large numbers on its LCD screen the received signal level (from the Subscriber
Transceiver) when connected to the Transceiver in lieu of (or in parallel with) the wireless cable
modem.
Connect the Sencore meter to the coaxial cable from the Subscriber Transceiver. Select the Install
main menu, and then DS Level
. Align the Transceiver by peaking the signal on the display.
The MSM980 is battery operated and has the additional feature that its battery can feed DC power
to the Subscriber Transceiver, so the installation can be completed outdoors without additional AC
power. Contact Sencore at 1-800-SENCORE (736-2673).
2.1.5 Spectrum Analyzer
Connect the spectrum analyzer in place of or in parallel (via a 2-way splitter) with the wireless cable
modem. Adjust the spectrum analyzer to display the downstream IF signal from the Subscriber
Transceiver (which will be between 425 and 525 MHz). Reduce the frequency span and adjust the
amplitude to achieve a trace similar to the one below.
-50
-40
-30
-20
-10
0
10
20
30
40
435
440
445
450
455
460
465
470
475
480
485
Ref Level :
40.0 dBmV
dB / Div :
10.0 dB
Spectrum Analyzer
GOOD
Model: MS2711B Serial #: 00215050
Date: 05/23/2002 Time: 11:55:01
RBW: 1 MHz VBW: 30 kHz Detection: Average
CF: 459.0 MHz SPAN: 50.0 MHz Attenuation: 0 dB
dBmV
Frequency (434.0 - 484.0 MHz)
Figure 2-5: Proper Downstream IF input to subscriber’s modem.
The spectrum analyzer settings were as in Table 2-1:
June 2003 Page 2-5