Preamplifier; Attenuator - Icom IC-9100 Instruction Manual

5
FUNCTIONS FOR RECEIVE
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.
The AG-25, AG-35 or AG-1200*
required for 144, 430 or 1200 MHz*
band in the Set mode. (pp. 165, 166)
amp OFF, preamp 1 ON or preamp 2 ON.
preamp 1 or preamp 2 is ON.
Wide dynamic range preamplifier. It is most
P. AMP
effective for the 1.8 to 21 MHz bands.
High-gain preamplifier. It is most effective
P. AMP
for the 24 to 50 MHz bands.
preamplifier unit ON or OFF, if installed.
OFF.
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 [P.AMP/ATT] for 1 second to turn ON the

Attenuator.

ON.
Push [P.AMP/ATT] momentarily to turn it OFF.
The Preamplifier and Attenuator are switched with [P.AMP/ATT], as shown below.
71
1
preamplifier unit is
2
frequency band.
" or "P. AMP " is displayed when the
2
*
P.AMP P.AMP
OFF
Push
P.AMP
OFF
Push
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.AMP 1" or "P.AMP OFF" setting.
Preamp 2 is most effective when:
weak.
antennas, or while using a narrow band antenna.
(such as small loop, a Beverage antenna or a short
1
* AG-1200 has been discontinued, but it can be still be
used.
2
* The optional UX-9100 is required for 1200 MHz frequency
band operation.
Hold down
P.AMP
Push
Hold down
P.AMP
ON
Push
[P TT]
[P TT]
ATT ON
ATT ON