Re: Notching out one frequency


Allan Isaacs
 

George

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

http://www.radiomuseum.co.uk/SDR.html

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

 

Simon,

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

Thanks,

George

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