Vertex Standard FT-950 manual FLT Roofing Filters, Am/Fm/Fm-Pkt, Lsb/Usb/Pkt, Cw/Rtty

FT-950

Operating Manual

VFO-A and VFO-B.

On the 10 MHz and lower bands, it generally is not necessary to use any preamplifier at all; selecting the “ON” position described above will increase the strong-signal-handling capability of the receiver, and generally will result in more pleasant reception due to reduced noise. If you can hear band noise with the preamplifiers disengaged, then a preamplifier is generally not needed.

R.FLT (Roofing Filters)

Narrow-band Roofing Filters of 15 kHz, 6 kHz, and 3 kHz bandwidths are provided in the first IF, right after the first mixer. These filters provide protection for the 2nd mixer, DSP, and other circuitry that follow and can dramatically improve reception on a very crowded band (during a contest, etc.). Typically, the AUTO selection mode is satisfactory for most operating situations, but in an extremely crowded phone band you may wish to select, for example, the 3 kHz roofing filter for SSB operation.

Press the [R.FLT] button to toggle the Roofing Filter selection. AUTO 15 kHz 6 kHz 3 kHz AUTO

Advice:

As you repeatedly press the [R.FLT] button, you will observe changes in the notation in the R.FLT column of the Block Diagram Display on the display, denoting the Roofing Filter currently in use.

Typically, this selection will be set to “AUTO.”

The Roofing Filter selection will be memorized independently on each VFO stack of the VFO-A and VFO-B.

Quick Point:

The “AUTO” selection of the Roofing Filter is based on the operating mode. However, you may override the automatic selection, if band conditions warrant a different (usually, a tighter) selection.

The AUTO mode Roofing Filter selections are shown below:

AM/FM/FM-PKT	15 kHz
LSB/USB/PKT	6 kHz
CW/RTTY	3 kHz

When the Roofing filter mode is set to “AUTO” and the Noise Blanker is turned On, the Roofing Filter bandwidth will automatically be set to 15 kHz, as this setting provides the most effective noise blanking. However, you still may override the

48 Vertex Standard Co., Ltd.