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Notch Filter Question

Posted: Wed Aug 26, 2020 2:35 pm
by Robert11

I imagine the screen to do it is "somewhere," but can't seem to find it.

Is it possible to create a Notch filter to notch out, e.g., a (selected) small am spread of frequencies with the program ?
Where, and/or how, please ?

(I know of the MW/FM Notch button in the ribbon, but would like to be able to select what free's I want notched out)


I see in the Receive DSP the option the option: Notch OFF / Auto Enable box.
And if selected, the Level Slider.

Could someone please explain this a bit for me re what it does ?
What is it actually Notching, etc. ?


Re: Notch Filter Question

Posted: Wed Aug 26, 2020 2:41 pm
by G0OFE
It's an audio notch - eliminates carriers within the demodulated area automatically in SSB mode. The level slider controls how strong it notches.

There is not currently any other notch function in Console.

From OP: Re: Notch Filter Question

Posted: Wed Aug 26, 2020 8:02 pm
by Robert111
Hi Jim,

Thanks for reply.

Seems like it might be a worthwhile item to add to Simon's "Wish List"

Regards, and stay well,

Re: Notch Filter Question

Posted: Wed Aug 26, 2020 8:32 pm
by G0OFE
Indeed.. it has been suggested before by myself to block spot freqs before demodulation (to try and remove narrow but strong local carriers killing weak broadcast FM signals on Band 2) but it's not a simple matter. There may be a solution, but Simon has a lot of other priorities, understandably this is not high on the list at this time.

I have moved this post to the "Requests" sub-board, as it is more appropriate there.

Re: Notch Filter Question

Posted: Sun Sep 13, 2020 7:55 am
by steamfire
How would I null out birdies if there's no user adjustable notch filter?

I am trying to decode an AFSK signal 50khz wide, but it is straddling two birdies/DC offsets from a HackRF. The birdies are stronger than the AFSK tones most of the time, and are present when the transmitter is not turned on, so it's not a signal carrier from my data transmitter. I'd like to notch those two frequencies down.

If this is not possible, how do I export the IF recording compatible with other SDR apps that have notch filters?


Re: Notch Filter Question

Posted: Mon Sep 14, 2020 6:13 am
by Simon G4ELI
I'm afraid there's nothing you can do until I add a manual notch / notches.