Kenwood TS-890S Operation Manual - Page 87

6 REJECTING INTERFERENCE REJECTING INTERFERENCE 6 Attenuator The attenuator is a function for attenuating the RX signals. If there is interference due to strong signals near the target signal, turning on the attenuator helps to reduce interference caused by nearby frequencies. It is also effective in situations where the RX audio is distorted when the RX signal is too strong. This transceiver comes with three different types of attenuators. Press F [ATT]. Pressing F [ATT] each time switches the attenuation level. Setting Value Off (default)/ 6 dB/ 12 dB/ 18 dB • Pressing and holding F [ATT] each time switches the options in the reverse sequence. • The attenuation level is stored for each antenna selection band. • The status of the attenuator (attenuation level) is displayed in the key guide. Filter Scope The following information is displayed on the filter scope screen. • Selected RX filter (A, B or C) • Image of the RX filter passband characteristics (trapezoid) • Audio spectrum of the RX audio • Parameters including the IF filter passband width • Pitch frequency in the CW mode • Notch point of the notch filter • Passband width of the roofing filter 44# $8 '4, .. Switching the RX Filter Band Characteristics Switching the RX Filter (A, B, C) The setting for the band characteristics of the RX filter on this transceiver can be switched at one touch according to the operating status to one of the three types (A, B or C). • The band characteristics are configured by combining the roofing filter or IF and AF filter, high cutoff/low cutoff and WIDTH/ SHIFT. A different RX filter setting (A, B or C) can be stored for each of the SSB, CW, FSK, PSK, FM and AM modes. Press [IF FIL]. Pressing [IF FIL] each time switches the RX filter in the order of "A", "B" and "C". • The selected filter is displayed at the top left of the filter scope. The RX filter does not switch to Type C if Menu [6-10] "RX Filter Numbers" below is configured to "2". Configuring the Selectable Types of RX Filters The selectable types of RX filters can be configured to three (A, B and C) or two (A and B). Configure in Menu [6-10] "RX Filter Numbers" Setting Value 2/ 3 (default) 14, ".'. ● The audio spectrum is not shown on the filter scope while the audio scope screen is displayed. ● The audio spectrum is not shown on the filter scope while the RTTY/PSK communication screen is displayed. ● An out-of-range marker is displayed when the image of the passband cannot be displayed within the display area because the shift amount of the filter in the CW mode is large. ● The audio spectrum is usually displayed within the image of the passband. However, it may be displayed beyond the image of the passband if there are excessively high input signals. ● When the notch filter is ON, the indicator representing the notch point is displayed in white. The indicator is displayed in white when the notch point is on the positive side of the carrier wave in the AM mode. If the notch point moves towards the minus side of the carrier wave, the indicator changes to orange and moves from the left edge of the screen to the right edge. 6-1