4-11
4
RECEIVE MODES
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Convenient functions for FSK
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About FSK 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 FSK signals correctly, select FSK-R mode.
➥ During FSK mode, push and hold [FSK] for 1 sec.
to select FSK and FSK-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 FSK signals.
➥ During FSK mode, push [APF/TPF] to turn the twin
peak filter ON and OFF.
•“ ” appears in the LCD and the [APF/TPF] indica-
tor 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 normal,
not a malfunction.
• Preamp (p. 5-9)
➥ Push [P.AMP] several times to set the preamp
OFF, preamp 1 ON or preamp 2 ON. Only
ON/OFF is available above 30 MHz.
•“P.AMP1” or “P.AMP2” appears when the preamp 1 or
preamp 2 is ON below 30 MHz. “P.AMP ON” appears
above 30 MHz.
• Attenuator (p. 5-9)
➥ Push [ATT] several times to set the attenuator in
6 dB steps for HF bands, or 10 dB step for
30–1150 MHz. Only 20 dB is available for
1150–3335 MHz.
•“ATT” and attenuation level appear when the attenu-
ator is ON.
• Noise blanker (p. 5-15)
➥ Push [NB] switch to turn the noise blanker ON
and OFF, and then rotate [NB] control to adjust
the threshold level.
• Noise blanker indicator (above [NB] switch) lights
when the noise blanker is ON.
• Push [NB] for 1 sec. to enter noise blanker set mode.
•Twin PBT (passband tuning) (p. 5-11)
➥ Rotate [TWIN PBT] controls (inner/outer).
• Push [PBT CLEAR] to clear the settings.
• Noise reduction (p. 5-16)
➥ Push [NR] switch to turn the noise reduction ON
and 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. 5-16)
➥ Push [NOTCH1] or [NOTCH2] switch to turn the
manual notch function ON or OFF.
• Rotate [NOTCH] control to set the notch frequency.
• Notch indicator (above [NOTCH1] or [NOTCH2]
switch) lights when either the manual notch is ON.
• AGC (auto gain control) (p. 5-10)
➥ 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.
