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4-1
BASIC MANUAL
4
RECEIVING AND TRANSMITTING
Preamplifiers
The preamp amplifies received signals in the
receiver front end to improve the signal-to-noise
ratio and sensitivity. A preamp is used when
receiving weak signals.
L
Each band memorizes the Preamplifier setting.
1. Push
.
• Opens the FUNCTION screen.
2. Touch [P.AMP/ATT] or [P.AMP].
L
In the HF or 50 MHz band, touching
[P.AMP/ATT] selects P.AMP1, P.AMP2, or OFF.
L
In the 144 or 430 MHz band, touching [P.AMP]
turns this function ON or OFF
3. To close the FUNCTION screen, push
.
HF
50 MHz
P.AMP 1
Wide dynamic range
preamplifier. It is most
effective for the HF low bands.
P.AMP 2
High-gain preamplifier. It is
most effective for the higher
bands.
144 MHz
430 MHz P.AMP
Amplifies received signals.
NOTE:
When you use the preamp while
receiving strong signals, the receiving signal may
be distorted. In such case, turn OFF the preamp.
Attenuator
Except for 144 and 430 bands
The Attenuator prevents a desired signal from
becoming distorted when a very strong signal
is near the frequency, or when a very strong
electric field, such as from a broadcasting
station, is near your location.
L
Each band memorizes the Attenuator setting.
1. Push
.
• Opens the FUNCTION screen.
2. Touch [P.AMP/ATT] for 1 second.
L
Touching [P.AMP/ATT] again turns OFF the
Attenuator.
3. To close the FUNCTION screen, push
.
L
If a strong signal is received and “OVF” (Overflow)
is displayed, turn ON the attenuator, or reduce the
RF gain until “OVF” disappears. (p. 3-8)
Displayed when
a preamp is ON.
Displayed when
the Attenuator
is ON.
Summary of Contents for IC-705
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