Cooling Section; Output Section - NEC PCN-1815SSQN/1Cx2 Instruction Manual

30kw vhf analog tv transmitter
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3-3

Cooling Section

This transmitter is cooled with coolant fed from an external pump rack. The coolant
which flows into the transmitter is branched to cool the PAs and then cools the resistors for
the combiner and is discharged, combined again into one route, from the transmitter.
For details, refer to the Instruction Manual of liquid cooling system (HO2-344491-2**),
Pump Rack (HO2-344492-2**) in section 6, and Heat Balance in 1, General, of Vol. II.
3-4

Output Section

This section consists of the low pass filter for rejecting the spurious of the outputs of the
power amplifier section.
Fig. 3-7 shows the schematic diagram of this section
Filter Size
NAX-77D
NAX-39D
Output of PA
LOW PASS
FILTER
Fig.3-7 Schematic Diagram
Table 3-3 Attenuation characteristic of filter
Attenuation[dB]
500MHz ~
600MHz ~
15
3 - 7
Output Antenna
700MHz ~
25
30
GWP-G22906

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