Nautel GV3.5, Operation & Maintenance Manual, Page: 13 / 251

GV5/GV3.5 OPERATIONS & MAINTENANCE MANUAL DESCRIPTION
VERSION 0.2 2014-07-23 PAGE 3.1.5
2-Way RF Drive Splitter/Attenuator
The 2-way RF drive splitter/attenuator PWB (A7A2) accepts the outputs from the splitter/changeover
PWB’s 3 dB hybrid coupler and splits it into two equal amplitude signals, using two 3 dB couplers
identical to A7A1U1. The outputs of the 3 dB couplers are applied to attenuators, as required, for
application to the two RF power modules. Attenuation values are set in order to balance the RF drive
output levels.
RF Power Stage
See electrical schematic Figure SD-4. The RF power stage accepts the intermediate RF drive inputs from
the RF drive stage and generates the final RF output. It consists of two RF power modules, the module
control/interface PWB (A3), a 10 kW combiner/filter (A12), an output power probe (A15), a 2-input
reject load assembly (A13) and a 2-way fan tray assembly (A14).
RF Power Module
See electrical schematic Figure SD-34. Each of the two RF power modules provides up to 3000 W (for
GV5) or 2250 W (for GV3.5) of RF output power. Each module contains four power amplifier (PA) PWBs
(A1 through A4), a splitter/interface PWB (A5), combiner PWBs (A6 and A7), and six cooling fans. The
intermediate RF drive outputs from the RF drive stage are applied to the RF power modules via the
module control/interface PWB (A3). Within each RF power module, the RF drive signal is sampled and
then split to drive the module's four PAs. The PA Volts inputs from the associated power supply modules
control the RF output of the four PAs.