fldigi Question

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I have a Flex-6700 running SmartSDR 1.7.30 and am using fldigi 3.23.09. I have downloaded and copied the XML files dated January 2016 to the appropriate location on my PC and have selected the XML file for Slice A in fldigi and I am using a single slice in SmartSDR.

I am able to make contacts just fine using a wide filter such as 2x4 or 2x3 in fldigi. If I want to QSY to the "sweet spot" of 1500 Hz, I just hit the QSY button and the signal of interest is centered on 1500 Hz as expected. If I then select a narrow filter, the filter is NOT centered on 1500 Hz and I, of course, cannot copy the signal. My question is therefore, how can I get the filter to center on the sweet spot so that I can take advantage of the narrow bandwidth? 

It has probably been a year or so since I have used fldigi, so am I forgetting something or is there something about SmartSDR 1.7.30 that has changed how the XML files work?

Thanks in advance for your help!

Ed, K0KC
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Ed, K0KC

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Posted 3 years ago

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Tim - W4TME, Customer Experience Manager

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I presume you are using the DIGU mode.  What is the size of the largest preset filter that exhibits this behavior?
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Ed, K0KC

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Tim,

Thanks for your reply!

Yes, I am using DIGU. There are eight filter selections in Fldigi: 1x1...2x4 as you surely know since you wrote the XML files. If I QSY a signal to 1500 Hz and then select any of those filters, they start at 0 Hz rather than being centered on 1500 Hz. The only exceptions are 2x3 and 2x4 which cover the entire 3 KHz on the Fldigi waterfall and thus are centered on 1500 Hz (actually, 2x4 is a 5 KHz filter which must be centered on 2.5 KHz, but the span of the waterfall is only 3 KHz).

Ed, K0KC
(Edited)
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Tim - W4TME, Customer Experience Manager

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That sounds like you are not using DIGU, but USB.  I just set my FLDIGI up and it is centering at 1500 Hz as it is set up in Fldigi as the sweetspot and in SmartSDR for the DSP offset.

Regardless of the preset filter, it centers at 1500 Hz.
(Edited)
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Ed, K0KC

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Tim,

Fldigi indicates that I am on DIGU and the 6700 shows DIGU...anyplace else to check?

Are the January 2016 XML files the latest?

Ed, K0KC
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Tim - W4TME, Customer Experience Manager

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Are the January 2016 XML files the latest?

Yes.
(Edited)
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Ed, K0KC

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Official Response
Tim,

The last time that I used Fldigi, I do not think the DSP Offset was available in SmartSDR. It was defaulted at 0...I changed it to 1500 and the filters are centered.

What is changed besides Fldigi with the DSP offset set to 1500?

Ed, K0KC
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Tim - W4TME, Customer Experience Manager

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The default DSP offset for DIGU is 1500.  Not sure of any mechanism that can change it except the operator of a FlexLib app.  Or you have not done a factory reset since the DSP offset was added and the default changed to 1500 Hz
(Edited)
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Ed, K0KC

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Tim,

I can assure you that I did not knowingly change the DSP offset to 0 Hz as I was not even aware that it existed. I probably have not done a factory reset since DSP offset was introduced.

My question was: will setting it to 1500 affect any other digital applications?

Anyhow, thanks for helping me solve this problem.

Ed, K0KC
(Edited)
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Tim - W4TME, Customer Experience Manager

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It should be fine for all narrow band digital Mose except RTTY and we have a special mode for it.