Re: Notching out one frequency

Allan Isaacs


Try making a simple bandstop filter.

See my LPF I made the other day using a couple of on-line calculators. One for the filter and another for coil construction.

Scroll down to the bottom of this page

Use simple coils, nothing fancy. My results were just about spot on and using your SDR itself to fine tune the filter you should get 50dB attenuation with a 7 order elliptic bandstop filter. Try 1220-1260KHz. Best results will be using the setting Exact rather than Standard values.

Allan G3PIY

From: [] On Behalf Of George Stein - NJ3H via Groups.Io
Sent: 27 March 2020 21:46
Subject: Re: [SDR-Radio] Notching out one frequency



Attached are two pics.  In the Elad picture the gap in the waterfall is the time I had my bcb filter engaged.

The SdrC picture shows station signals behind the "cloud" of QRM from the local station.

I have tried calling the station, but no answer.  The station is mostly automated.  with the covid thing going on, they must not be at the office.  As I mentioned in my first message, this is a new situation.  You can see the station is a measly 60 over S9 here.  What a weak reception.  lol lol



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