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. > > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
