User's Manual

Page 56 FTDX5000 OPERATING MANUAL
R.FLT
(
ROOFING FILTERS
)
Narrow-band Roofing Filters of 15 kHz, 6 kHz, 3 kHz, 600 Hz
Ú
, and 300 Hz
Ú
bandwidths are provided in the first IF, right
after the first mixer. These filters provide protection fort the 2nd mixer, DSP, and other circuitry that follow and can
dramatically improve reception on a very crowded band (during a contest, etc.). Typically, the AUTO selection mode is
satisfactory for most operating situations, but in an extremely crowded phone band you may wish to select, for example, the
3 kHz roofing filter for SSB operation.
Ú
:
The roofing filter of 600 Hz is select in VFO-A only (The roof filter of 600Hz can not select in VFO-B). Furthermore,
the roofing filter of 300 Hz is select in VFO-A of the MP version only (The roof filter of 300Hz is optional in the other
versions).
I NTERFERENCE R EJECTION
(
S IGNALS O FF F REQUENCY BY J UST A F EW KHZ
)
VFO-A Roofing Filter Setup
 Press the
[
A
]
button (the imbedded LED in the
[
A
]
button is glows red), if desired.
 Move the
[
R.FLT
]
knob up and down to set the de-
sired bandwidth of the VFO-A Roofing Filter.
The selected bandwidth of the Roofing Filter will be
indicated in the R.FLT column of the Receiver Con-
figuration Indicator on the display.
VFO-B Roofing Filter Setup
 Press the
[
B
]
button (the imbedded LED in the
[
B
]
button is glows orange).
 Move the
[
R.FLT
]
knob up and down to set the de-
sired bandwidth of the VFO-B Roofing Filter.
The selected bandwidth of the Roofing Filter will be
indicated in the R.FLT column of the Receiver Con-
figuration Indicator on the display.
ADVICE:
 The Roofing Filter selection will be memorized inde-
pendently on each VFO in the VFO stack.
QUICK POINT:
 The AUTO mode Roofing Filter selections are shown
below:
AM/FM/FM-PKT: 15 kHz
LSB/USB/PKT: 6 kHz
CW/RTTY: 3 kHz
 Press the
[
R.FLT
]
knob briefly to select the Roofing
Filter setting to “AUTO”, that selection of the Roofing
Filter is based on the operating mode. When the Roof-
ing Filter setting is to “AUTO”, the bandwhidth of the
Roofing Filter will blink for three seconds and there-
after will appear continuously. Typically, this selection
will be set to “AUTO”.
 Press the
[
R.FLT
]
knob briefly to select the Roofing
Filter setting to “AUTO”, that selection of the Roofing
Filter is based on the operating mode. When the Roof-
ing Filter setting is to “AUTO”, the bandwhidth of the
Roofing Filter will blink for three seconds and there-
after will appear continuously. Typically, this selection
will be set to “AUTO”.
TERMINOLOGY:
A “Roofing Filter,” as its name implies, places a “Roof”
over the receiver’s IF system bandwidth. This “Roof” pro-
tects the circuitry downstream from the first mixer from
interference, just as a roof on a house protects the contents
from rain and snow.
[
A
]
Button
[
R.FLT
]
Knob
[
B
]
Button
[
R.FLT
]
Knob
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