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L860 Manual.qxd
12/2/05
2:21 PM
Installation
L860
Setup and Installation
1. Mount unit securely by attaching screws or bolts through mounting tabs of unit and into an equipment rack.
2. Attach the source RF signal to the input of the L860.
3. Attach the distribution RF cable to the output of the L860.
4. Connect unit power cord to wall receptacle or power strip supplying line power.
5. Connect an RF spectrum analyzer or signal level meter to the input test point.
6. Use the loading chart listed on page 3 as a guide to ensure that the input level does not exceed the suggested
amplitude level for the number of channels. If needed, reduce the input level using plug in attenuators
(MACOM-AT-*).
7. Connect a RF spectrum analyzer or signal level meter to the output test point.
8. Adjust the amplifier output level to match the distribution amplitude and tilt requirements.
9. If 5-36MHz return RF signals are present, measure the input level at the output "-20 dB" TEST point location.
Using plug in attenuators (MACOM-AT-*) to ensure that the return input level is between 1 to 25 dBmV. Adjust the
"RETURN PATH GAIN" control to match distribution system design requirements.
Note: The channel loading chart on a previous page shows the proper operation level for the L860.
The setup procedure above and loading restrictions assume that the RF source channels are all received at the
same amplitude level. Please note the listed performance criteria is for SPECIFIC numbers of channels, and must
be de-rated accordingly when inserting additional channels. Also note the amplifier's gain does not change.
However, as the number of channels increases from 7 channels, the input level (and hence, the output level) must
be reduced. Exceeding the input levels listed below will cause intermodulation and picture distortions.
10. The output levels of the modulators should be the same as the output of the off-air strip amplifiers. The M860
modulators are usually combined with either the SP860 signal processor or XBS series strip amplifiers.
11. The PHC-12G twelve channel and PHC-24G or C860 twenty-four channel combiners consist of two rows of
directional couplers combined by a hybrid splitter. The directional coupler combining provides high isolation (50 dB)
between the inputs. Normally, the odd channels are combined on one row while even channels are combined on the
other row of directional couplers. The combiner loss is 18 dB per channel for the PHC-12G, 21 dB per channel for
the PHC-24G, and 31 dB per channel for the C860. The outputs of the amplifiers are connected to the main
distribution line.
6
Ph: 800-421-6511
Rev. 12/05
Page 6
www.picomacom.com
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