I Preamp/Attenuator; I Rit Function - Icom IC-7400 Instruction Manual

5
FUNCTIONS FOR RECEIVE

I Preamp/Attenuator

The preamp amplifies received signals in the front end
circuit to improve the S/N ratio and sensitivity. Set this
to preamp 1 or preamp 2 when receiving weak signals.
The attenuator prevents a desired signal from distor-
tion when very strong signals are near the desired fre-
quency or when very strong electric fields, such as
from broadcasting stations, are near your location.
These can both set independently for each band.
➥ Push [P.AMP/ATT] several times to set the preamp
OFF, preamp 1 ON or preamp 2 ON.
• When the preamp is ON, either "P.AMP 1" or
"P.AMP 2" appears in the function display.
• When operating on the 144 MHz band, the preamp can
only be set to ON or OFF only— there is no preamp 1
and preamp 2.
Regular preamp, the most effective for 1.8 to
21 MHz bands without IMD corruption.
High-gain preamp, the most effective for 24
to 50 MHz bands.
Preamp activates for the VHF band
146 MHz range; 108 to 174 for the USA version)
➥ Push [P.AMP/ATT] for 1 sec. to set the attenuator ON.
• "ATT" appears in the display when the function is set ON.
• Push [P.AMP/ATT] momentarily to set the attenuator OFF.
Regarding the use of the "P.AMP
The "P.AMP 2" is a high gain receive amplifier. When the
"P.AMP 2" is used during times of strong electric fields, dis-
tortion sometimes results. In such cases, use the trans-
ceiver with the "P.AMP 1" or "P.AMP OFF" setting.

I RIT function

The RIT (Receive Increment Tuning) function compen-
sates for off-frequencies of the communicating station.
The function shifts the receive frequency up to
±9.99 kHz in 10 Hz steps without moving the transmit
frequency.
• See #0 on p. 4 for function description.
q Push [RIT] to turn the RIT function ON and OFF.
• "RIT" and the shifting frequency appear when the func-
tion is ON.
w Rotate the [RIT/∂TX] control.
• Push [CLEAR] for 1 sec. to reset the RIT frequency.
• Push [CLEAR] momentarily to reset the RIT frequency
when the quick RIT clear function is ON. (p. 86)
• Push [RIT] for 1 sec. to add the shift frequency to the op-
erating frequency.
D D RIT monitor function
When the RIT function is ON, pushing and holding
[XFC] allows you to monitor the operating frequency
directly (RIT is temporarily cancelled).
47
(144 to
.
2
"
[P.AMP/ATT]
Push
P.AMP/ATT
Push
P.AMP/ATT
Push
P.AMP/ATT
The "P.AMP 2" is most effective when:
• Used on bands above 24 MHz and when electric fields are
weak.
• Receive sensitivity is insufficient during low gain, or while
using a narrow band antenna
age antenna or a short Yagi antenna, etc.)
Appears
Push
P.AMP/ATT
Push for 1sec.
P.AMP/ATT
(such as small loop, a Bever-
is used.
[CLEAR]
[RIT] [RIT/∂TX] control