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Saturday, 24 August 2013

TS-990; Hows the filtering?


Since my TS-990 came home with me I've been spending some time understanding the filters and their configuration. You basically have, in each mode, three sets of filters that you can pre-configure. The configuration comprises the roofing filter, IF and AF filter shape. On top of this you can also then configure the IF width.

In FSK mode, I've set mine so that the filters are:

In addition to this I have configure the selections so that the IF bandwidth is 1500Hz when FIL-A is selected, 500Hz for FIL-B and 250Hz for FIL-C. This alone is allowing me to reject very close and swamping signals from a crowded RTTY band. Additionally this radio has an Audio Peak Filter for FSK or RTTY mode which will also include a null or notch between the mark and space tones. Here's a decode window without the APF:

And here with:

So I tune round the band with a wider filter selection, perhaps starting with A and then moving to B. Once I find an individual signal I then switch to filter C and include the APF if there is another signal intertwined with the one I am interested in.

Here's a quick video to try and illustrate this in action:

The video isn't very good quality, but you get the idea.

Here's the new ham cat who has taken to sleeping inside a cupboard:

Fun, egh?

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