RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS

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glovisol
Posts: 69
Joined: Thu May 10, 2018 6:42 pm

Re: RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS

Postby glovisol » Thu Jul 12, 2018 7:52 am

ANTENNA INDUSTRIAL NOISE SUPPRESSION AT 3.5 & 7 MHz WITH HIGHPASS FILTER

More illustrations below.
Attachments
Noise filter schematic.jpg
Filter example for initial testing
Noise filter schematic.jpg (58.95 KiB) Viewed 104 times
Noise filter.JPG
Badly constructed prototype is still effective
Noise filter.JPG (88.16 KiB) Viewed 104 times

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glovisol
Posts: 69
Joined: Thu May 10, 2018 6:42 pm

Re: RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS

Postby glovisol » Thu Jul 12, 2018 9:45 am

...But this Butterworth n=6 in a balanced configuration seems to work much better! Industrial noise has gone, 3.5 to 14 MHz. Noise floor is now close to - 135 dBm on all these bands! Await confirmation from other Forum dwellers.

glovisol

IMPORTANT ERRATA CORRIGE as of 13/07/18: The original balanced filter schematic had a serioud error in that all capacitor values were wrong. I have removed the wrong schematic and replaced it with the revised version with correct capacitance values. Sincere apologies, glovisol
Attachments
Noise filter schematic.jpg
REVISED Balanced noise filter schematic
Noise filter schematic.jpg (59.2 KiB) Viewed 57 times

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glovisol
Posts: 69
Joined: Thu May 10, 2018 6:42 pm

Re: RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS

Postby glovisol » Fri Jul 13, 2018 11:48 am

Please be aware that in the balanced n=6 filter schematic in the previous post all capacitance values were wrong. I have now replaced the wrong schematic with the correct version. Sincere apologies,

glovisol

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