______________________________________________HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
22
15 kW (Standard)
In a 15 kW system, the AGC module’s output feeds a driver module, which drives a
PA module. In a low band transmitter, the PA’s output is split in a 16-way divider,
whose outputs feed 16 PA modules. The outputs are recombined in a 16-way
combiner, whose output becomes the cabinet’s visual output.
In high band transmitters, the same principle applies, except that 17 PA modules and
17-way dividers and combiners are used.
The 30, 45, and 60 kW transmitter visual chains are multiples of this basic 15 kW
architecture.
30 kW (Standard)
In a 30 kW transmitter, the AGC output passes through a phase and gain module. In
high band systems, the two outputs are sent to two preamps. In low band systems, the
preamps are not necessary.
The resulting outputs are sent to two 15 kW visual cabinets (see 15 kW system,
above). The cabinet outputs are combined with a 3 dB quadrature hybrid combiner.
45 kW (Standard)
In a 45 kW system, one phase and gain module feeds one visual cabinet and a
preamp, whose output feeds a second phase and gain module. Three outputs are thus
obtained. In high band systems, a preamp is inserted in each path at this point, and
the three outputs pass to the aural PA and visual driver cabinet. In low band systems,
these three preamps are omitted.
The three outputs are each fed to driver modules. In low band systems, the driver
outputs are each passed to one of three PA modules, whose outputs each drive a 15
kW visual PA cabinet (see 15 kW system, above).
In high band systems, each of the three drivers supplies input to a pair of PA
modules. The PAs are paralleled into pairs using two-way power dividers and
combiners. The three outputs then pass to three 15 kW visual cabinets (see 15 kW
system, above).
At the outputs of the three visual PA cabinets, a 3 dB hybrid combines the first two
visual cabinet outputs, which combine with the third in a 4.77/1.76 dB asymmetrical
hybrid combiner. The combined output passes through a harmonic and color notch
filter on its way to the optional diplexer.
60 kW (Standard)
The AGC module output feeds a phase and gain module, whose outputs feed two
more phase and gain modules.
To Next Page
Loading...
