[Lowfer] noise cancelling at lf

[Chris Trask]

>
> Looking at the thread about noise cancelling I remembered a post by LLoyd
Butler vk5br
> see http://users.tpg.com.au/users/ldbutler/LFNoiseCancel.htm
>
> We had a discussion of this about a year ago.
>

    Butler's designs are actually quite nice for LW applications.  He at
least has some semblance of phase control in the design.  Some commercial
units, such as those from MFJ and Timewave, have a "phase control" that is
anything but a phase control, consisting of a transistor, two resistors, and
a pot.  You go from +1 to -1 from one end of the pot to the other, and they
claim that it's a phase control even though you're only going from 0-degrees
to 180 degrees and nothing in between.

Chris

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