Yaesu FT-847, Руководство по эксплуатации

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21
FT-847 O
PERATING
M
ANUAL
Front Panel Controls & Switches
(5) MIC
Jack
This 8-pin connector accepts microphone input, as well
as providing PTT, ground, and scanning control ac-
cess. Optimum microphone impedance is 500
Ω
~
600
Ω
.
(6) MIC/RF PWR
Controls
The inner MIC control adjusts the microphone input
level in the SSB, AM, and FM modes (see Menu #25
on page 86 regarding FM operation). Clockwise rota-
tion increases the microphone gain level.
The outer
RF PWR
control adjusts the transmitter’s
power output, and adjustment is available in all modes.
Clockwise rotation increases the power output.
(7) SQL/KEYER SPEED
Controls
The inner SQL control sets the signal threshold at
which receiver audio is muted (in all modes). Most
frequently used during FM operation, this control must
be rotated fully counter-clockwise for most SSB, CW,
or AM operation.
The outer KEYER SPEED control sets the sending
speed for the built-in Electronic Keyer. Clockwise ro-
tation increases the sending speed.
(8) ATT
Switch
This switch may be used to insert a 10 dB attenuator
in the receiver front end to minimize the potential for
overload. The “
ATT
” icon will appear on the display
when the attenuator is on. Best receiver sensitivity will,
of course, occur when no attenuation is used.
(9) AGC-F
Switch
Pressing this switch activates “Fast” recovery time for
the receiver’s Automatic Gain Control system. The
“AGC-F” selection is generally preferred for CW op-
eration and, on SSB, during rapid-fading conditions.
(10) PROC/KEYER
Switch
This is a dual-function switch, the effect of which de-
pends on the operating mode:
l
In the SSB mode, pressing this switch activates
the RF Speech Processor, which provides en-
hanced “talk power” for use under difficult con-
ditions. When activated, the “
PROC
” icon will
appear on the display panel.
l
In the CW mode, pressing this switch activates
the built-in Electronic Keyer circuit. When ac-
tivated, the “
KEYER
” icon will appear on the
display panel.
(11) RF AMP
Switch
This switch turns the receiver RF preamplifiers on and
off. When this switch is pressed, the “
RF AMP
” icon
will appear on the display panel, signifying that the
receiver input preamplifier is activated. When this
switch is pressed again, “
RF AMP
” will disappear, and
the preamp will be bypassed. Best receiver sensitivity
occurs when the RF preamplifier is on; however, in a
noisy location (or on the HF bands below about 10
MHz) the RF preamplifier may not be necessary.
(12) NB
Switch
Pressing this switch activates the IF N oise B lanker,
which may help reduce many different types of man-
made impulse noise (but not atmospherics). When the
Noise Blanker is activated, the “
NB
” icon will appear
on the display panel.
(13) MONI
Switch
Pressing this switch activates the SSB voice monitor,
which allows the operator to monitor voice character-
istics during adjustment of, for example, the Speech
Processor. In the CW mode, pressing this switch acti-
vates the CW sidetone monitor. In either mode, the
“
M O N I
” icon will appear when the monitor is acti-
vated. The M
ONITOR
feature does not, however, func-
tion in the SSB mode during Satellite operation, as it
would interfere with your ability to monitor your own
downlink signal.
(14) AF/RF
Controls
The inner AF control adjusts the receiver volume level
presented to the speaker or headphones (but not the
rear panel
PKT
or
DATA IN/OUT
jacks). Clockwise
rotation increases the volume level.
The outer
RF
control adjusts the gain of the receiver’s
RF and IF stages. Clockwise rotation increases the RF
Gain level for best sensitivity, and the normal operat-
ing position for this control is fully clockwise.
Note : Counter-clockwise rotation of the
RF
(G
AIN
)
control, besides lowering the receiver gain level,
will cause the S-meter to deflect upward, as
though a strong signal were present. This is quite
normal.