Yaesu FT-991 User Manual

Page 53FT-991 OperaTing Manual
iF notch Filter operAtion
(
SSb/cW/rtty/dAtA/AM ModeS
)
TheIFNOTCHlterisahighlyeffectivesystemthatallowscuttingoutaninterferingbeatnoteorothercarriersignal
frominsidethereceiverpassband.
1. Press the
F(MLIST)
buttontoshowthefunctions
listed on the TFT display.
2. Touch
[
NOTCH
]
ontheTFTdisplay.TheNotch
functionwillbesetto“
ON
”.
MULTI Knob
F(M-LIST) Button
NOTCH indicator
NOTCH level indicator
3. Rotatethe
MULTI
knobtoadjustthe“null”position
oftheNotchlter.
4. TocanceltheNOTCHlter,touch
[
NOTCH
]
on the
TFT display, “
OFF
”will appear inthe display,con-
rmingthattheNOTCHlterisnolongerinopera-
tion.
Advice:

Alternate touches of
[
NOTCH
]
, will switch the
NOTCHlterbetweenonandoff.
Advice:

 The bandwidth of theNOTCH lter (either narrow
orwide)maybeadjustedusingMenuitem“
116
IF NOTCH WIDTH
”.Thefactorydefaultsettingis
“
WIDE
”.
TheperformanceoftheIFNOTCHlterisillus-
trated in Figure “
A
”,wherethedesiredsignaland
the interfering heterodyne are shown within the
IFpassband.InFigure“B”thenotchingeffectof
theIFNOTCHlterisillustratedasthe
MULTI
knobis rotated toeliminate theinterfering het-
erodyne.
A B
Desired Signal Desired Signal
QRM
(Heterodyne)
QRM
(Heterodyne)
IF BANDWIDTH IF BANDWIDTH
MULTI
interference reJection

Yaesu FT-991 Specifications

General

Frequency Range Transmit	1.8 MHz - 54 MHz, 144 MHz - 148 MHz, 430 MHz - 450 MHz
Antenna Impedance	50 Ohms
Antenna Connector	SO-239
Supply Voltage	13.8 V DC ±15%
Modes	SSB, CW, AM, FM, C4FM Digital
Display	3.5-inch color TFT LCD
Weight	4.3 kg