BendixKing KHF 990 - Manual (Page 40)

Using the KCU 951 or KFS 594, if the system detects a fault during
transmission or during the tuning of the antenna coupler, the frequen-
cy digits on the display begin to flash. Simply key the mic and the
automatic antenna coupler begins a new tuning cycle to clear the
fault.
TUNING FAULTS
If the antenna coupler is unable to find an acceptable
frequency/antenna match, the fault indication continues at the end of
the tuning cycle. If repeated antenna tuning cycles fail to clear the
fault indication from the display, there is probably an equipment mal-
function.
KHF 950/990 CONTROLS-GENERAL
Operating the KHF 950/990 requires that the pilot first determine the
correct mode to match the ground station, whether it be upper side-
band (USB), lower sideband (LSB), or AM. Correct mode selection is
essential for successful contact with a ground station. Most stations
use USB mode, but some continue to use AM. Also, the pilot must
determine whether simplex, semi-duplex or receive-only frequency
operation is required to match the operation of the desired ground
station.
THERE ARE SEPARATE OPERATING SECTIONS ON EACH OF
THE CONTROL DISPLAY UNITS. READ ONLY THE SECTION
WHICH PERTAINS TO THE CONTROL DISPLAY UNIT YOU HAVE
INSTALLED WITH YOUR KHF 950/990.
Operation
3-3 KHF 950/990 Pilots Guide
Rev. 0
Dec/96