Thank's for comment audiocaos!
I use a Icom 718 with DSP an this Noise canceling is working in some situation's. For my analog receivers i would like to use something against noise from local electronik like TV's and other's.
Do not use this kind of analog Noise canceling systems at the present time.
I just think about this stuff,because with the, for example, Datong FL3 you filtering the noise from Audio but the ''Noise'' is comming first through the full receiver stage. I'm interested if this work so good. Why preamp bad stuff if you don't like it..
The other solution will be a MFJ 1026.. it work's full into other direction to filter the bad signal's bevor it come to the antenna jack from receiver.
At my two QTH's i god strong local QRM and so i want to do something
(..and i do not want to steal the ''Neighbors TV'' and the other stuff to listen to a quite HF

)