Yaesu FT dx 1200 Operating Manual page 19

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PHONES Jack
A 1/4-inch, 3-contact jack accepts either monaural or
stereo headphones with 2- or 3-contact plugs. When
a plug is inserted, the loudspeaker is disabled.
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When wearing headphones, we recommend that you
turn the AF Gain levels down to their lowest settings
before turning power on, to minimize the impact on
your hearing caused by audio "pops" during switch-
on.
MIC Jack
This 8-pin jack accepts input from a microphone uti-
lizing a traditional YAESU HF transceiver pinout.
[ ANT ] Switch
Pressing this switch selects the ANT 1 or the ANT
2 connector on the rear panel, and allows convenient
antenna switching at the press of a button. The se-
lected antenna jack is indicated on the Key Function
Display shown in the TFT Display.
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The ANT2 jack may be enabled to use as a receive
only antenna, using the Menu item "033 ANT2 SET-
TING". See page 114.
[ IPO ] ( i
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This button may be used to
end characteristics of the receiver circuit for a very
strong signal environment. Available selections are
AMP 1 (low distortion amplifier), AMP 2 (2-stage
low-distortion RF amplifier), or IPO (bypasses the
front end RF amplifier). The selected receiver RF
amplifier appears in the IPO column of the Key
Function Display on the display.
[ ATT ] Switch
This button selects the degree of attenuation, if any,
to be applied to the receiver input.
Available selections are –6 dB, –12 dB, –18 dB, or
OFF. The attenuation level appears in the ATT col-
umn of the Key Function Display on the display.
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The Attenuator may be used in conjunction with the
[ IPO ] button to provide additional signal reduction
when an extremely strong signal is being received.
[ R.FLT ] ( r
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ooFing ilter
This button selects the bandwidth of the receiver first
IF Roofing Filter. Available selections are 3 kHz, 6
kHz, 15 kHz, or Auto.
The selected bandwidth appears in the R.FLT column
of the Key Function Display on the TFT display.
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 The "AUTO" selection mode selects the optimum
bandwidth of the Roofing filter for the reception
mode. In this case, the selected bandwidth in
the R.FLT column of the Key Function Display
glows green (The unselected choices glow Blue).
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 Because the roofing filter is in the first IF, the
protection it provides against interference is quite
significant. When set to AUTO, the SSB band-
width is 6 kHz, CW, RTTY and DATA, the band-
width is 3 kHz, while AM and FM is 15 kHz.
[ NB ] Switch
This button turns the IF Noise Blanker on and off.
Press this button momentarily to reduce short-dura-
tion pulse noise.
Available selections are ON, OFF, or NBW ON. The
attenuation level appears in the NB column of the
Key Function Display on the display.
[ AGC ] Switch
This button selects the AGC characteristics for the
receiver. Available selections are FAST, MID, SLOW
and OFF, or AUTO. The selected AGC characteris-
tic appears in the AGC column of the Key Function
Display on the TFT display.
Press the [ AGC ] button
sired receiver-recovery time constant. Press and hold
in the [ AGC ] button for one second to disable the
AGC (for testing or weak-signal reception).
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 The "AUTO" selection mode selects the charac-
teristic of the AGC for the reception mode. The
selected AGC characteristic will glow green in
the AGC column of the Key Function Display,
(unselected characteristics glow Blue).
 The Attenuator may be used in conjunction with
the [ IPO ] button to provide two stages of signal
reduction when an extremely strong signal is be-
ing received.
 If the AGC receiver-recovery time is set to "Off"
by pressing and holding in the [ AGC ] button, the
S-meter will no longer deflect. Additionally, you
will likely encounter distortion on stronger sig-
nals, as the IF amplifiers and the following stages
are probably being overloaded.
[ MOX ] Switch
Pressing this button engages the PTT (Push to Talk)
circuit to activate the transmitter (the
LED indicators area illuminates and the "MOX" icon
will appear in the TFT display). It must be turned off
(the icons will disappear) for reception. This button
replicates the action of the Push to Talk (PTT) switch
on the microphone. When engaging the [ MOX ] but-
ton, or otherwise causing a transmission to be start-
ed, be certain you have either an antenna or 50-Ohm
dummy load connected to the selected Antenna jack.
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witches
repeatedly to select the de-
icon in the
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