Platinum Z5 CD - Detailed RF Theory of Operation

4-4 888-2408-002
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
This also allows the PA Modules to be HOT-PLUGGABLE, meaning that a PA
module may be removed while the transmitter is operating. Interlock pins on the
module connectors mute the PA modules before it switches out the unplugged
module.
4.2.4 5kW Hybrid Combiner
The 2.5kW outputs from Z-Plane A and Z-Plane B are combined in a 3dB Hybrid
which is specially fit in between the two Z-Planes. The 5kW output from the hybrid
passes through an aluminum box under the PA (in the Power Supply Compartment)
and connects to the transmission line Harmonic Filter at the top rear of this box. The
harmonic filter connects to the output flange on the top rear of the transmitter. The
Harmonic Filter has 3 directional couplers. One is for Forward Power, one is for
Reflected Power and the third is left available for on site use as a Demodulator or
analyzer sample. The couplers are designed for at least 30dB directivity.
4.3 Detailed RF Theory of Operation
The exciter theory is described in a separate technical manual included with the
transmitter. Each of the remaining RF sections of the transmitter are described in the
following paragraphs.
4.3.1 Exciter Operation
The exciter output is basically fixed and should not require adjustment. The exciter
power output is set using the controls on the front of the exciter and should be set to
the “Exciter Power” reading on the factory test data sheet for the transmitter. For
information on setting exciter power, refer to the exciter manual.
4.3.1.1 Automatic Exciter Switching
If a second or backup exciter is installed and the on air exciter fails, the controller
will automatically switch to the backup exciter and log the fault. Note that the
controller will wait 10 seconds for the on-air exciter to recover before switching to
the backup. If a backup exciter is added anytime after factory testing, the installer
must go into the Configuration Menus on the Diagnostic Display and set “ALT
EXCITER” to YES to let the controller know that the backup exciter exists. If this is
not done the controller will not auto switch.
4.3.1.2 Manual Exciter Switching
For dual exciter configurations, the on-air exciter can be selected manually using
the Diagnostics Display. The exciter select screen is located in the Status menus and
shown in Figure 4-2. For exact location, refer to the “Diagnostics Display Menu
Tree” drawing in the schematic package. Manual exciter switching can also be done
via the configurable remote input. See Table 2-1 on page 2-28 for more information
on this remote control input.