Section 5 Functions For Receive; Preamp And Attenuator; D Preamplifier; Attenuator - Icom IC-7100 Advanced Instructions

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5
FUNCTIONS FOR RECEIVE

Preamp and attenuator

D Preamplifier

The preamplifier amplifies weak signals in the receiver
front end, to improve the S/N ratio and sensitivity.
Turn this function ON when receiving weak signals.
(Frequency band: HF, 50/70 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 preamplifier is OFF.
Wide dynamic range preamplifier. It is most
P.AMP1
effective for the 1.8 to 21 MHz bands.
High-gain preamplifier. It is most effective
P.AMP2
for the 24 to 70 MHz bands.
(Frequency band: 144/430 MHz)
➥ Push (C) turn the Preamplifier ON or OFF.
P.AMP
ATT
• "P.AMP" appears when the preamplifier 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 fields,
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 Preamplifier and Attenuator switching procedure
Push or hold down
P.AMP
ATT
• HF, 50/70 MHz frequency bands
• 144/430 MHz frequency bands
(C) to switch the Preamplifier and Attenuator, as shown below.
P.AMP P.AMP1 P.AMP2
OFF ON
Push
P.AMP
ATT
P.AMP
OFF
Push P.AMP
ATT
✔ About the "P.AMP2" preamplifier
The preamp 2 is a high gain receive amplifier. When
it is used in the presence of strong electromagnetic
fields, distortion sometimes results. In such cases,
use either 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 insufficient when using low-
gain antennas, or while using a narrow band anten-
na. (such as small loop, a Beverage antenna or a
short Yagi antenna)
Hold down
ON
Push
P.AMP
Hold down
P.AMP
ON
Push
P.AMP
5-2
P.AMP
ATT
P.AMP
ATT
P.AMP
ATT
ATT ON
ATT
P.AMP
ATT
ATT ON
ATT