D Convenient Functions For Receive; D About Rtty Reverse Mode; D Twin Peak Filter - Icom IC-7800 Instruction Manual

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RECEIVE AND TRANSMIT

D Convenient functions for receive

• Preamp (p. 5-10)
➥ Push [P.AMP] several times to set the preamp
OFF, preamp 1 ON or preamp 2 ON.
• "P.AMP1" or "P.AMP2" appears when the preamp 1
or preamp 2 is ON. Main and sub have independent
preamp controls.
• Attenuator (p. 5-10)
➥ Push [ATT] several times to set the attenuator in
6 dB steps.
• Hold down [ATT] for 1 second to set the attenuator in
3 dB steps.
• "ATT" and attenuation level appear when the attenu-
ator is ON.
• Noise blanker (p. 5-18)
➥ Push [NB] switch 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 the noise
blanker set mode.
• Twin PBT (passband tuning) (p. 5-13)
➥ Rotate [TWIN PBT] controls (inner/outer).
• Hold down [PBT CLEAR] for 1 second to clear the
settings.

D About RTTY reverse mode

Normal
170 Hz 2125 Hz
Space Mark
BFO

D Twin peak filter

Reverse
2125 Hz 170 Hz
Space Mark
BFO
[APF/TPF] [APF/TPF]
(MAIN) (SUB)
• Noise reduction (p. 5-19)
➥ Push [NR] switch 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.
• Notch filter (p. 5-20)
➥ Push [NOTCH] switch to turn the manual notch
function ON or OFF.
• Rotate [NOTCH] control to set the attenuating fre-
quency.
• Notch indicator (above [NOTCH] switch) lights when
either the auto or 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 ⁄ function (p. 3-6)
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➥ Push [1/4] to turn the
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.
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.
• "
" 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 re-
ceived audio output may increase. This is a normal,
not a malfunction.
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1 ⁄ function ON or OFF.
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