Hi Peter,
Would this type of noise canceler not work on "white" noise also ?
73,
Marinos, ki4gin
From: "Peter Zenker" <[EMAIL PROTECTED]>
To: "'Marinos Markomanolakis, M.D.'"
<[EMAIL PROTECTED]>,<elecraft@mailman.qth.net>
Subject: RE: [Elecraft] RF Noise canceller ?
Date: Sun, 3 Apr 2005 13:03:51 +0200
Hello Marinos,
There have been several schematics using such technics over the last 20
years. Most of them use a seperate short antenna, feeding the signal pase
shifted into a combiner which combines the main Antenna Signal with the
phases shifted extra antenna signal. This construction can reduce a lot of
man made noise.
I remember there was a commercial available stand alone unit sold by a
small
english company.
I myself built such a unit to help reducing my noise problem especialy at
160m (I live in the middle of Berlin, Noise level in the evening is > S7)
But I forgot the unit during the time because I do not have an 160m Antenna
any longer.
73 de Peter, DL2FI
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of
> Marinos Markomanolakis, M.D.
> Sent: Sunday, April 03, 2005 6:45 AM
> To: elecraft@mailman.qth.net
> Subject: [Elecraft] RF Noise canceller ?
>
> Just a question for the technically inclined group members:
>
> How feasible or worth the effort, would be the addition of an
> option to the
> K2 which would sample RF noise from a ferquency close to the used
> band,(tunable?) which is devoid of signals, phase invert and
> reinject the noise to an IF stage or even the antenna input
> in order to cancel our the "white or pulse" noise components,
> preserving the desired signal ?
>
> Why similar circuits are not preferred in HF receiver designs
> instead of DSP filters ?
>
> Similar circuits are commonly used in biomedical devices
> (called linear averagers if I am not mistaken) and are very
> effective in isolating electric signals from a particular
> organ eg Heart in EKG or brain area of interest in EEG,
> filtering out the irrelevant noise from the muscle cells...
>
> Just some food for thought.
>
>
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