Yaesu FT DX 3000 Operating Manual

Also see for FT DX 3000: Operating manual Operating manual Operating manual Operating manual Operating manual

Contents

Page 54 FT DX 3000 O peraTing M anualA B CinTerFerence rejecTiOnwidtH (iF dSp bANdwidtH) tuNiNg (SSb/cw/Rtty/pKt ModeS)The IF WIDTH tuning system allows you to vary the width of the DSP IF passband, to reduce or eliminate interference.Moreover, the bandwidth may actually be expanded from its default setting, should you wish to enhance incoming sig-nal fidelity when interference on the band is low.1. Rotate the [WIDTH] knob to the left or right to re-duce the interference.A dvice :The frequency display will show the bandwidth ofthe IF passband for 3 seconds whenever the [WIDTH]knob is turned.[WIDTH] KnobA dvice :The IF Bandwidth will be memorized independently oneach VFO stack of VFO-A and VFO-B.Referring to Figure “B”, you can see the defaultbandwidth on the SSB mode.By rotating the [WIDTH] knob to the left, thebandwidth will narrow (see Figure “A”, whilerotation of the [WIDTH] knob to the right, asdepicted in Figure “C”, will increase the band-width.A B CThe default bandwidths, and total bandwidth ad-justment range, will vary according to the operat-ing mode:SSB Mode: 1.8 kHz ~ 4.0 kHz (default: 2.4 kHz).CW Mode: 500 Hz ~ 2.4 kHz (default: 2.4 kHz)RTTY/DATA Modes: 500 Hz ~ 2.4 kHz (default:500 Hz)Using IF SHIFT and WIDTH TogetherThe IF SHIFT and Variable IF WIDTH featurestogether form a very effective interference-fight-ing filtering system.For example, in Figure “A”, you can see howinterference has appeared both on the highand low sides of the desired signal. Rotate the[WIDTH] knob, the interference from one sidecan be eliminated (Figure “B”). Next, rotate the[SHIFT] knob to re-position the passband (Figure“C”), the interference on the opposite side can beremoved, without re-introducing the interferencepreviously eliminated in Figure “B”.A dvice:For best interference reduction, the WIDTH andSHIFT features are the primary tools you shoulduse, after narrowing the bandwidth (WIDTH)and/or adjusting the center of the passband(SHIFT). The Contour control may then yieldadditional signal-enhancement benefits onthe net residual bandwidth. Even more, the IFNOTCH Filter (described later) may also beused, in conjunction with these filter systems, tosignificant advantage.widtH iNdicAtoRIF BANDWIDTH IF BANDWIDTH IF BANDWIDTHSHIFT SHIFT SHIFT Desired Signal Desired Signal Desired SignalQRMQRMQRMQRMQRMQRMIF BANDWIDTH IF BANDWIDTH IF BANDWIDTH