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AR5000 OPERATING MANUAL PAGE 25
Manually selecting I.F. bandwidth.
The sequence
activates the I.F. bandwidth
menu.
In normal operation the word “
AUT
AUT
AUT
AUT
AUT
” will be displayed in
the upper right of the LCD to signify that automode is in
operation and the I.F. bandwidth, receive mode and
channel step will be automatically selected by the AR5000
from its detailed pre-programmed bandplan data.
Selecting a new bandwidth from the list of 220, 110, 30,
15, 6 and 3 kHz is accomplished using the
SUB DIAL
, 0.5
kHz is only available if the optional CW filter has been
fitted. To accept the new bandwidth selection press
Once automode has been cancelled, it may be reinstated
from the MODE select menu or by pressing and holding
the
key for more than one second.
I.F. filter bandwidth table:
Filter kHz
Total nose
Total skirt
(b’width kHz / dB)
0.5(500Hz) opt
0.5 -3
2.0 -60
2.5 opt
2.5 -3
5.2 -60
3
2.4 -6
4.5 -60
5.5 opt
5.5 -3
11.0 -60
6
9.0 -6
20 -50
15
15 -6
30 -50
30
30 -6
70 -50
110
140 -3
350 -20
220
260 -3
520 -20
6-11 AF SET - (Audio characteristics)
It is possible to optimise the audio settings of the AR5000,
there are a total of 5 different settings relating to the audio
characteristics:
1) Low pass filter
A-LPF 3.0
kHz
2) High pass filter
A-HPF 0.3
kHz
3) De-emphasis
DE.EMP 750
4) CW pitch
CW.PITCH 0.7
kHz
5) Input switching
AUDIO INT
1 Audio Low Pass Filter
The audio low pass filter is useful to cut off high tones
(allowing low tones to pass) to improve intelligibility of weak
signals in close proximity to adjacent interference and to
remove hiss making listening for extended periods easier
on the ears.
There are four available cut off frequencies: 3.0 kHz,
4.0kHz, 6.0kHz & 12.0 kHz. The lower the frequency the
more limited the audio bandwidth... for highest fidelity for
Band-II listening select 12.0 kHz. If the filter selection has
been left to automode, the legend “
AUT
AUT
AUT
AUT
AUT
” will be displayed.
The audio low pass filter will initially be automatically
selected according to the IF bandwidth:
Bandwidth
Audio Low Pass Filter
0.5 kHz to 15 kHz 3.0 kHz
Above 30 kHz
12.0 kHz
The audio low pass filter selection is accessed via a
sub menu.
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
kHz <<<
A-HPF 0.05
kHz
DE.EMP 750
CW.PITCH 0.7
kHz
AUDIO INT
1. Press
. The LCD will show, for example,
“
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
A-LPF 3.0
kHz”.
2. Rotate the
SUB DIAL
to make selection: 3.0 kHz, 4.0kHz,
6.0kHz or 12.0kHz.
3. Press
to accept the changes,
to abort
or
to move on to the audio high pass filter selection.
2 Audio High Pass Filter
The audio high pass filter is useful for limiting the audio
bass response (allowing higher tones to pass) improving
intelligibility in certain circumstances (such as low
frequency whistles on AM, SSB & CW).
There are four available high pass frequencies: 0.05 kHz
(50 Hz), 0.02 kHz (200 Hz), 0.3kHz (300 Hz) & 0.4 kHz
(400 Hz). The higher the frequency the more limited the
audio bandwidth... for highest fidelity for Band-II VFO
listening select 0.05 kHz. If the filter selection has been
set to automode, the legend “
AUT
AUT
AUT
AUT
AUT
” will be displayed.
The audio high pass filter will initially be automatically
selected according to the IF bandwidth:
Bandwidth
Audio High Pass Filter
0.5 kHz to 15 kHz 0.3 kHz (300 Hz)
Above 30 kHz
0.05 kHz (50 Hz)