FS71C-85 Series User Manual
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Copyright © 2015 Fiber-Span
Downlink Setup
To setup the downlink, the following equipment is
required:
1. RF signal generator
2. Spectrum analyzer
3. Appropriate jumper cables
The following steps should be observed to properly set
up the link.
At the Antenna Port, measure the composite RF signal
level delivered by the signal generator (or donor an-
tenna when in the fi eld).
Use a suitable Spectrum Analyzer capable of measuring
composite RF within the required bandwidth. The best
way to measure the composite signal level is to setup
the Spectrum Analyzer to measure the total carrier
power within the bandwidth of the downlink amplifi er.
Carrier level is not the same as composite power over
the bandwidth.
1. Enable a channel in the GUI by setting the test fre-
quency and enabling the channel and ticking the
AGC column. Set BW to 25kHz, Gain adjust to 0dB
and set Squelch to -90 dBm,
2. Ensure that the measured composite RF signal lev-
el at the RF input port is no greater than -10dBm.
3. At the output Antenna Port, measure the composite
RF
4. Set gain such that output is approxi37
dBm (or one channel) by setting the Gain adjust
levels in the Downlink GUI page.
5. Measure and verify that the composite RF output
power at the DAS port is approxi37dBm.
6. Note: Factory limit is set to +37 dBm composite
output power
7. For a two tone test, repeat steps 1 - 4 for a second
frequency. Reduce the output level per the derat-
ing on page 20
NOTE: The derating table applies only when the test
tones are random (e.g. off air signals) . If test tones are
generated by test equipmnet, be sure the two genera-
tors do not use a common synchronized clock source.
Non-random synchronized signals would require a
much more accelerated derating.
NOTE: When connecting directly to an antenna, the
maximum downlink antenna gain must not exceed 4.85
dBd and the cable loss from DAS port to antenna must
not be less than 5 dB. The maximum uplink antenna
gain must not exceed -2.15 dBd.
