Yaesu FT-767GX Operating Manual

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l f background noise is strong enough to causeche S-meter to deflect above S-3, switch offthe Rf AMP. l f the S-meter still deflects onthe noise, and if more than S-3, tum theATTenuator on.l f the S-mecer deflects, but to less than S-3,tum the RF gain control counterclockwisegradually ua til the S-meter just begi ns torise, and then drop the Rf gain back a littlet o the threshold point. Your receiver is aowset for maximum useful sensitivity on thatband (the settings are different at differenttimes.• on different bands, and with differentantennas and station locations).On the other hand, if the background noisecauses no S-meter defleccion, you may needmore receiver gain: switch off the ATTenuatori f it is on, and i f still no S-meter deflection, switch on the Rf AMP (they should neverboth be on together). As soon as you see alittle S - meter deflection, adjust the RF gainas just described.Note: Remember: there is no advantage tosetting receiver gain higher than what isnecessary to receive signals above thebackground noise. The S-meter can be setto read higher on signals and noise, butthis usually causes the receiver to bemore susceptible to distortion from strongsignals,qualicy.decreasing overall receptionFor best reception quality, ai-ways use the minimum sensitivity needed.4.13.2 Strong Signal SSB ReceptionFor strong signal reception, follow the sarnesteps as above. Set the AGC to slow, and turnthe RF gain back as much as possible so thatyou can stil l hear the incoming signal duringany fading that may occur. When the receiveri s set properly, s í g n a l - t o - noise q u a l i t yshould be almost as good as FM.4.13.3 Suppresslng Man -made Interference1 f unwanted stations are heard near the signalyou are listening to, first make sure you haveyour station tuned in precisely (press CLAR ifyou retune during a QSO), and then press OLOCK to disable the tuning knob. Now try rotating the SHIFT control slightly. Noticechat the pitch of the signals will shift, andyou may be able to reduce the interferencewhile stili copying. The TONE control can behelpful in correcting for the altered pitchcaused by SHIFT adjustment.l f the SHIFT adjustment does not help, thelnterference might not be due to nearby signals, b u t to intermodulation from strongsignals on far frequencies. If the stationyou are listening to is strong enough, turnoff the Rf AMP, tum on the ATTenuator, andreduce the RF gain, one at a time in thatorder, stopping while the desired station iss t i i l readable.Make certaln to re-center the SHIFT controlbefore you turn the O LOCK off and retune.for heterodyne interference such as from A Mstations, or for rnany types of 'buzzing' signals such as those used for jamming on the HFbands, the NOTCH filter can be helpful. PressD LOCK to disable the tuning knob, and thenlurn on the NOTCH filter and adjust it verygradually for a dip ln the interference (shownon the S-meter).Remember to tum the NOTCH fllter off beforeturning the O LOCK off and retuning.4.13.4 MiscellaneaUse care when tuning in an SSB signal, andthen press O LOCK so you can make fíne adjustments to the IF passband and audio withouthaving them suddenly upset by an accidentalbump of the luning knob. Use the memories fornet or schedule frequencies.- 30 -