Icom IC-7410 Instruction Manual - Page 62

5 FUNCTIONS FOR RECEIVE ■ 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. ➥ Push [P.AMP•ATT] one or more times to set the preamp OFF, preamp 1 ON or preamp 2 ON. • Either "P. AMP " or "P. AMP " is displayed when the preamp 1 or preamp 2 is ON. • N o indicator is displayed when the preamp is OFF. P. AMP P. AMP Wide dynamic range preamplifier. It is most effective for 1.8 to 21 MHz bands. High-gain preamplifier. It is most effective for 24 to 50 MHz bands. [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.AMP 1" 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 antenna. ■ 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 [P.AMP•ATT] for 1 second to turn ON the Attenuator. • "ATT" appears when the Attenuator is ON. ➥ Push [P.AMP•ATT] momentarily to turn OFF it. [P.AMP•ATT] About the Preamplifier and Attenuator switching procedure The Preamplifier and Attenuator are switched with [P.AMP/ATT], as shown below. P.AMP OFF P.AMP Push P.AMP Hold down Push ATT ON 55