In Addition to the TNF Notch filter, How about a TPF or Tracking Passband Filter too? SmartSDR

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  • Updated 9 months ago

My thought here is to make a fast pass band filter without excessive mouse dragging.  Please chime in if my description leaves you asking more questions .....

I play a lot in the digital bands where the frequency is set but, the audio changes the real frequency .... as in PSK, FT8, and JT etc. So the Bandwidth starts off wide, 1.5kc to 3kc wide.

Right now if I want to close up the passband on any signal, CW, RTTY, SSB, or Digital I have to hit one of the buttons or use the mouse to drag the passband closed. 

CW, RTTY, SSB this is OK, but on the digital forms like FT8 and JT the freq is set and the audio bandwdith varies to set the "Real Freq"  In DIGU mode normally you would start open at 3kc or 1.5kc and close it up as needed.  Seldom is the desired signal in the perfect bandwidth so you can use the buttons so you need to drag the bandwidth with the mouse and set both sides.

What I was thinking is the ability to punch up a pass filter like you do with the TNF but instead of a notch, it changes the pass band and then allows the mouse to change the width with a up/down motion like the notch filter.  So I would just right click on the desired signal and the passband would close onto that frequency  and down to a set bandwidth, say 100hz and then with an up or down motion change the bandwidth wide or narrow (just like the notch filter)

I was thinking if you right click on the diplay the Create Slice, Create TNF and add "Create TPF"  (Tracking Pass Filter) and when finished, just like the notch filter the same delete box.

Sorry if I was long winded, but I wasnt sure if I could explain it right.

Respectfully, Brian WD9HSY 

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Brian Bedoe WD9HSY

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Posted 9 months ago

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Brad A. Steffler

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Great idea. Is there already a macro type of facility, buried in the software, that would do this for us?

Brad KE4XJ
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Alex - DH2ID, Elmer

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Decoding digital modes needs no bandpass, as you need to see ALL the stations on the digital band.
Just leave the bandwidth at 5kc and use DIGU. Decoding and showing stations will be done by HRD or fldigi and WSJT-X. Even if very strong stations are on the band, I have never had to use a narrower bandwidth than 5kc to get good decodes. You can't compare digital modes to RTTY and CW, where a narrow bandwidth might be essential to filter out the desired signal.
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dan flynn

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For optimum SNR you always want to match your filter to the width of the signal you are trying to detect.
(Edited)
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Brian Bedoe WD9HSY

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Alex, closing up the bandwiidth does make a difference in congested bands ..... try it
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Dick B

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What you want is exactly what I do using DM780 macros for PSK and other non-JT digital modes - it's perfect - on both my IC-756 Pro3 and also on my Flex 6300 as well.  I have macros for various bandwidths down to 50 Hz and they are very effective.  Since WSJT-X and SmartSDR have no such macro facility, how about trying the macros in DDUtil?  I've only created one DDUtil macro, for my antenna tuner, so don't know if it's possible but may be worth a try.  Setting the Center frequency could be an issue.  
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Mark Erbaugh

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MixW has an ALIGN macro which changes the tuned frequency so that the currently selected audio frequency in the MixW waterfall is changed to a different frequency. I have a MixW macro that sends ALIGN:1500 to align the frequency to the center of the DIGU filter and then sends a CAT command to set the SSDR filter to 50 Hz. I have another macro to set the SSDR filter back to 3000 Hz.

HRD's DM780 has a built in setting for the center of the filter, called the sweet spot. With that set to 1500 Hz, a click of a button retunes to RF frequency so that its audio frequency is in the center of the DIGU passband.

The issue I have is that some software doesn't recognize DIGU and thinks that it is LSB (rather than USB), so it tunes in the wrong direction.
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Brian Bedoe WD9HSY

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But would'nt be nice if it was all in 1 program, rather than 3 -4 other programs all running at once? KISS, KISS!  To many little programs all doing our pet peeves?


(Edited)
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Milen KG2C

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As others noted, there are existing ways to modify the passband, once the frequency is set. The issue as I see it is that you prefer to use the pre-defined frequencies from WSJT-X, select a station from WSJT-X to contact (while seeing 3kHz or more) and then switch to the narrow pass band with one key stroke. I agree that a single key solution to this is preferable than reading the frequency manually from WSJT-X and making the adjustments in SSDR or through another tool.

This requires other software like DDUtil to know what is the frequency of that station you are trying to contact and what is the bandwidth of the mode you are currently using in WSJT-X.

Does anyone know if WSJT-X is currently able to supply this information through an API or by network connection, like it does for some of its communications with logging software? If not, perhaps this could be implemented better through JTAlert-X, which already reads the decodes from WSJT-X, and allows you to click on a station within it to set WSJT-X to reply to that station's CQ.
I would suggest discussing this with JTAlert-X's developer as this might be the most convenient way to go about this, for example by adding integration with DDUtil in JTAlert-X, so that when you click a station through JTAlert-X it also launches a DDUtil macro (that saves the current pass band state and sets your pass band to what you need). Perhaps with an option to launch a different macro when you send 73 or log the contact to return the pass band to the previous saved state.

Doing it this way will eliminate the need to fiddle with SSDR while enjoying WSJT-X, at the expense of having to run JTAlert-X and DDUtil in addition to WSJT-X and SSDR. I already use JTAlert-X anyway and will be using DDUtil once I get my Flex 6600 to get my auto tuner to track the radio, so it really isn't an issue for me.
You could eliminate the need for DDUtil if you can convince the JTAlert-X developer to implement the network commands to the Flex radio directly but you would lose out on the flexibility and customization DDUtil will offer.
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Brian Bedoe WD9HSY

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Passband filter, similar to the TNF but for Passband, in SmartSDR ...... not JTAlert, not DDutil, not in WSJT ...... This was a suggestion to the developers of SmartSDR
(Edited)