BendixKing KHF 990 - Manual (Page 101)

The KFS 594 MODE selector is the larger outer concentric knob
(lower right) which provides access to the USB, LSB and AM modes
for either simplex or semi-duplex operation. In addition it has posi-
tions marked “A3J” and “A3A” for the two formats of maritime
radiotelephone network (public correspondence) station channels.
Most of these stations operate in the A3J format. In the A3J and A3A
positions the pilot can access all 245 ITU public correspondence sta-
tion channels which are permanently stored in nonvolatile memory.
These channels are assigned numbers such as 417, 822, 1230, 1624
and 2236. (See list of International Channel Designations) Each
channel number corresponds to an assigned transmit and receive
frequency for semi-duplex operation in USB. For example, when call-
ing station KMI, Point Reyes, California using ITU channel 417, the
pilot is receiving on 4407.0 kHz and transmitting on 4112.6 kHz. The
transmit and receive frequencies are stored in memory, but it is only
the station channel 417 which will appear in the KFS 594 display
when you select that channel.
It is possible to operate in USB, LSB and AM modes using either a
direct tune operation, or a programmable channel operation in which
19 channels can be programmed by the pilot and stored for recall.
While direct tuning a frequency, only simplex operation may be used.
However, when utilizing the 19 programmable channels, either sim-
plex or semi-duplex operation may be used. The use of the
Frequency/Channel control knob and STO (store) switch are
explained in the following sections.
DIRECT TUNING A FREQUENCY
In direct tune operation, the pilot may select directly any of 280,000
frequencies in the range of 2.0 to 29.9999 Mhz. The frequencies
progress in 100 Hz intervals. Follow these three steps:
Operation
3-64 KHF 950/990 Pilots Guide
Rev. 0
Dec/96
1
S
T
O
HF
OFF
TEL AM
USB
LSB
A3J
A3A
VOL
SQ
345.6
19 12
CH M
H
Z
K
H
Z
Figure 3-78 Direct Tuning A Frequency