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Notch Filter Question

Robert11
Posts: 51
Joined: Fri Aug 21, 2020 8:49 pm

Notch Filter Question

#1

Unread post by Robert11 »

Hello,

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)

And,

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. ?

Thanks,
Bob

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G0OFE
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Joined: Thu Aug 06, 2020 7:33 am
Location: Sunny Sunny Bournemouth IO90BR
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Re: Notch Filter Question

#2

Unread post 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.
Jim, Bournemouth IO90BR
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Robert111
Posts: 11
Joined: Wed Aug 19, 2020 10:53 am

From OP: Re: Notch Filter Question

#3

Unread post 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,
Bob

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G0OFE
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Re: Notch Filter Question

#4

Unread post 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.
Jim, Bournemouth IO90BR
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steamfire
Posts: 1
Joined: Sun Sep 13, 2020 7:22 am

Re: Notch Filter Question

#5

Unread post 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?

Thanks,
Dan
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Birdies without the actual signal
Birdies without the actual signal
Signal overlaid on birdies
Signal overlaid on birdies

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Simon G4ELI
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Re: Notch Filter Question

#6

Unread post by Simon G4ELI »

I'm afraid there's nothing you can do until I add a manual notch / notches.
Simon Brown :shock:
www.sdr-radio.com

Do not send me direct e-mail, thank-you!

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