Yaesu FT DX 9000MP CONTEST - DATA MANAGEMENT..., Operation Manual

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Page 66 FT
DX
9000MP O
PERATION
M
ANUAL
ATT
Even with the IPO function on, extremely strong local signals or high noise can still degrade reception. In such situations,
you can use the [
ATT
] knob to insert 3, 6, 12, or 18-dB of RF attenuation in front of the RF amplifier.
M
AIN
(VFO-A) A
TTENUATOR
S
ETUP
Rotate the Main (VFO-A) side’s [ ATT
] switch to set the
desired attenuation level, per the chart below.
To restore full signal strength thorugh the Attenuator cir-
cuit area, set the [
ATT
] switch to the “0” position.
S
UB
(VFO-B) A
TTENUATOR
S
ETUP
Rotate the Sub (VFO-B) side’s [ ATT
] switch to set the
desired attenuation level, per the chart below.
To restore full signal strength thorugh the Attenuator cir-
cuit area, set the [
ATT
] switch to the “0” position.
A A
A A A
D D D D DVICE VICE VICE VICE VICE
If background noise causes the S-meter to deflect
on clear frequencies, turn the [
ATT
] knob clock-
wise until the S-meter drops to about “S-1.” This
setting optimizes the trade-offs between sensitiv-
ity, noise, and interference immunity. Also, once
you have tuned in a station you want to work, you
may want to reduce sensitivity further (or add more
attenuation) by turning the [
ATT
] knob to a more
clockwise setting. This reduces the strength of all
signals (and noise) and can make reception more
comfortable, important especially during long
QSOs.
When looking for weak signals on a quiet band,
you will want maximum sensitivity, so the IPO
should be disabled and the [
ATT
] knob should be
set to “0.” This situation is typical during quiet times
on frequencies above 21 MHz, and when using a
small or negative-gain receiving antenna on other
bands.
0 dB Attenuator is Off
3 dB The incoming signal power is reduced by 3 dB (signal volt-
age reduced by 1/1.4)
6 dB The incoming signal power is reduced by 6 dB (signal volt-
age reduced by 1/2)
12 dB The incoming signal power is reduced by 12 dB (signal volt-
age reduced by 1/4)
18 dB The incoming signal power is reduced by 18 dB (signal volt-
age reduced by 1/8)
MAIN(VFO-A) [ATT] Switch
CCCCC
ONVENIENT ONVENIENT
ONVENIENT ONVENIENT
ONVENIENT
F F F F F
EA EA
EA EA
EATURES TURES
TURES TURES
TURES
SUB(VFO-B) [ATT] Switch
VDD TEMP SWR BIAS