Section 5 Functions For Receive; Preamp And Attenuator; D Preamplifi Er; D Attenuator - Icom IC-7100 Instruction Manual

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5
FUNCTIONS FOR RECEIVE

Preamp and attenuator

D
Preamplifi er
The preamplifi er amplifi es weak signals in the receiver
front end, to improve the S/N ratio and sensitivity.
Turn ON this function when receiving weak signals.
(Frequency band: HF/50 MHz)
➥ Push
(C) one or more times to set the pre-
P.AMP
ATT
amp OFF, preamp 1 ON or preamp 2 ON.
• Either "P.AMP1" or "P.AMP2" is displayed when the pre-
amp 1 or preamp 2 is ON.
• No icon is displayed when the preamplifi er is OFF.
Wide dynamic range preamplifi er. It is most
P.AMP1
effective for the 1.8 to 21 MHz bands.
High-gain preamplifi er. It is most effective
P.AMP2
for the 24 to 50 MHz bands.
(Frequency band: 144/430 MHz)
➥ Push
(C) turn the Preamplifi er ON or OFF.
P.AMP ATT
• "P.AMP" appears when the preamplifi er is ON.
• No icon is displayed when it's OFF.
D
Attenuator
The attenuator prevents a desired signal from being
distorted when very strong signals are near the signal's
frequency, or when very strong electromagnetic fi elds,
such as from broadcast stations are near your location.
These can both be independently set for each band.
➥ Hold down
(C) for 1 second to turn ON the
P.AMP
ATT
Attenuator.
• "ATT" appears on the display when the Attenuator is ON.
➥ Push
(C) to turn it OFF.
P.AMP ATT
About the Preamplifi er and Attenuator switching procedure
Push or hold down
P.AMP
ATT
• HF/50 MHz frequency bands
P.AMP
• 144/430 MHz frequency bands
P.AMP
(C) to switch the Preamplifi er and Attenuator, as shown below.
P.AMP1 P.AMP2
OFF ON ON
Push
P.AMP ATT
P.AMP
OFF ON
P.AMP
Push ATT
P.AMP
✔ About the "P.AMP2" preamplifi er
Preamp 2 is a high gain receive amplifi er. When it is
used in the presence of strong electromagnetic fi elds,
distortion sometimes results. In such cases, use ei-
ther the "P.AMP1" or "P.AMP OFF" setting.
Preamp 2 is most effective when:
• Used on bands above 24 MHz and when signals are
weak.
• Receive sensitivity is insuffi cient when using low-
gain antennas, or while using a narrow band an-
tenna (such as small loop, a Beverage antenna or a
short Yagi antenna).
P.AMP
Hold down P.AMP
ATT
Push
P.AMP ATT
Hold down
P.AMP ATT
Push
P.AMP ATT
5-2
ATT
ATT
ATT ON
ATT ON