Yaesu FTDX-9000MP Operation Manual

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Page 65FTDX9000MP OPERATION MANUALRF G AIN (SSB/CW/AM M ODES)The RF Gain controls provide manual adjustment of the gain levels for the receiver RF and IF stages, to account for noiseand/or signal strength conditions at the moment.Main (VFO-A) RF Gain AdjustmentThe Main (VFO-A) RF GAIN control (# ) should,initially, be rotated to the fully clockwise position. tjhis isthe point of maximum sensitivity, and counter-clockwiserotation will gradually reduce the system gain. As the RF GAIN control control is rotated counter-clockwise to reduce the gain, the S-meter reading willrise. this indicates that the AGC voltage being appliedto the receiver (to reduce the gain) is increasing. Rotating the RF GAIN control control to the fullycounter-clockwise position will essentially disable thereceiver, as the gain will be greatly reduced. In thiscase, as well, the S-meter will appear to be “pegged”against the right edge of the analog S-meter scale. The Sub (VFO-B) receiver’s RF GAIN control(# ) operates identically to the Main (VFO-A) bandRF GAIN control. The effects of counter-clockwiserotation of the Sub receiver’s RF GAIN control maybe observed visually on the Sub (VFO-B) band S-meter.AdviceReception frequently can be optimized by rotating the RFGAIN control slightly counter-clockwise to the pointwhere the incoming noise level is just about the same asthe “stationary” meter needle position as set by the adjust-ment of the RF GAIN control. This setting ensures thatexcessive gain is not being utilized, without so much gainreduction that incoming signals cannot be heard.Quick PointThe RF Gain control, along with the IPO and Attenuatorfeatures, all affect the system receiver gain in differentways. As a first step in dealing with high noise or a crowded,high-level signal environment, the IPO generally shouldbe the first feature engaged, if the frequency is low enoughto allow the preamplifier to be bypassed. Thereafter, theRF Gain and Attenuator features may be employed to pro-vide precise, delicate adjustment of the receiver gain so asto optimize performance fully.MAIN (VFO-A)SUB (VFO-B)CONVENIENT F EATURESSUB(VFO-B) RF GAIN KnobMAIN(VFO-A) RF GAIN Knob