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4-14
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About RTTY reverse mode
Received characters are occasionally garbled when
the received signal has Mark and Space tones re-
versed. This reversal can be caused by incorrect TNC
connections, setting, commands, etc. To receive re-
versed RTTY signals correctly, select RTTY-R mode.
➥
During RTTY mode, hold down
RTTY/PSK
for
1 second to select RTTY and RTTY-R mode.
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Twin peak filter
The twin peak filter changes audio frequency response
by boosting the mark and space frequencies (2125
and 2295 Hz) for better reception of RTTY signals.
➥
During RTTY mode, push
APF/TPF
to turn the
twin peak filter ON or OFF.
•
“
TPF
” appears in the LCD and the [APF/TPF] indicator
above this switch lights green while the filter is in use.
NOTE:
When the twin peak filter is in use, the
received audio output may increase. This is a nor-
mal, not a malfunction.
APF/TPF
Normal
Reverse
Space Mark
BFO
Space Mark
BFO
170 Hz
2125 Hz
170 Hz
2125 Hz
4
RECEIVE AND TRANSMIT
• Preamp
(p. 5-10)
➥
Push [P.AMP]
(MF3)
several times to set the
preamp OFF, preamp 1 ON or preamp 2 ON.
• Hold down [P.AMP] (MF3)
for 1 second to turn the
preamp function OFF.
• “P.AMP1” or “P.AMP2” appears when the preamp 1
or preamp 2 is ON.
• Attenuator
(p. 5-10)
➥
Push [ATT]
(MF4)
several times to set the attenu-
ator in 6 dB steps.
• Hold down [ATT]
(MF4)
for 1 second to turn the
attenuator function OFF.
• “ATT” and attenuation level appear when the attenu
-
ator is ON.
• Noise blanker
(p. 5-17)
➥
Push
NB
to turn the noise blanker ON or
OFF, and then rotate [NB] control to adjust the
threshold level.
• Noise blanker indicator (above
NB
switch) lights
when the noise blanker is ON.
• Hold down
NB
for 1 second to enter noise blank-
er set mode.
• Twin PBT (passband tuning)
(p. 5-13)
➥
Rotate [TWIN PBT] controls (inner/outer).
• PBT indicator (above
PBT-CLR
switch) lights when
PBT is in use.
• Hold down
PBT-CLR
for 1 second to clear the set-
tings.
• Noise reduction
(p. 5-18)
➥
Push
NR
to turn the noise reduction ON or
OFF.
• Rotate [NR] control to adjust the noise reduction
level.
• Noise reduction indicator (above
NR
switch) lights
when the noise reduction is ON.
• Manual notch filter
(p. 5-19)
➥
Push
NOTCH
to turn the manual notch func-
tion ON or OFF.
• Rotate [NOTCH] control to set the attenuating fre
-
quency.
• Notch indicator (above
NOTCH
switch) lights when
the manual notch is ON.
• AGC (auto gain control)
(p. 5-12)
➥
Push [AGC] switch several times to select
AGC FAST, AGC MID or AGC SLOW.
➥
Push
AGC VR
to turn the AGC time constant
manual setting ON or OFF.
• Rotate [AGC] control to adjust the time constant.
•
1
⁄
4
function
(p. 3-6)
➥
Push [1/4] to turn the
1
⁄
4
function ON or OFF.
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Convenient functions for receive