Harris Atlas DVL1100, Technical Manual

Page: 125 / 180

2/25/03 888-2473-001 4-25
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Series™
Figure 4-10 2-Way RF System - DVL 800
4.4.5.1 Combiner Isolation Loads
The combiner isolation loads are actually 500W or 1kW, 40dB attenuators whose
output is taken to the RF Monitor Board for metering and protection. The RF
samples are detected by the RF Monitor Board and then minimised by adjusting the
module Phase and Gain from the control panel. The isolation loads are mounted on
the water cooled heatsink (or Cold Plate) on the side of the cabinet. Attenuators
AT1 - AT4 are 500W while attenuators AT5 - AT8 are 1kW each. AT5 and AT6 are
actually paralleled from the final output combiner in the 6 and 8-way systems for a
2kW total dissipation capability. The splitter used to feed AT5 and AT6 is also
mounted on the cold plate and labeled A7.
Figure 4-11 shows the physical location of each of the combiner reject loads as they
are mounted on the cold plate. There is also a table showing which loads are used
for each of the transmitter models.