Overview
Block Up Converter Systems 6700/6900 series User Guide 23
RF waveguide switches
RF waveguide switches control both the receive and transmit
RF paths. The switches direct signals for both on-line and off-
line BUCs and LNBs (when used). Transmit/receive C-Band
systems may use either two RF waveguide switches or one
combined RF waveguide/coaxial switch. Transmit/receive
Ku-Band systems use two RF waveguide switches only.
Transmit-only C-Band or Ku-Band systems use only a single
RF waveguide switch.
Systems using two RF waveguide switches
In the receive path, a receive RF waveguide switch directs the
received RF from the receive port of the antenna feed to one of
the LNBs. The LNB waveguide inputs are coupled to ports 1
and 3 of the LNB switch. The switch is coupled via port 2 to
the WR229 (C-Band) or WR75 (Ku-Band) receive port of the
antenna. A blanking plate normally protects port 4 from the
weather.
In the transmit path, a transmit RF waveguide switch directs
the transmitted RF from the on-line BUC to the transmit port
of the antenna feed. The RF from the off-line BUC is directed
to either a coaxial or a waveguide load.
For transmit RF, the waveguide outputs of the BUCs are
connected to the WR137 (C-Band) or WR75 (Ku-Band) BUC
switch via short waveguide sections to ports 1 and 3. Port 2 of
the switch connects to the antenna via flexible waveguide. A
load or power attenuator terminates port 4 on the switch.
The redundancy controller verifies RF waveguide switching
by monitoring the tell-back contacts of both switches. If the
tell-back contacts indicate an abnormal condition, the BUC
Switch or LNB Switch LEDs on the control panel of the
redundancy controller illuminate red.
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