You can sometimes get rid of noise with the ANC-4, but it has been my
experience the noise needs to be really local, such as your damn PC.

I use a Wellbrook ALA-100, which is their basic amp with a roll it
yourself loop. I will never go back to a long wire. I've built a DC
adapter for the Wellbrook (as discussed before, the thing is postive
ground so use caution.) Taking the Wellbrook out in the boonies, you
can experience low noise. At my house, forget it.

This is the small loop, about 3ft on a side.
http://www.lazygranch.com/images/radio/loop1.jpg
http://www.lazygranch.com/images/radio/loop2.jpg
http://www.lazygranch.com/images/radio/loop3.jpg
http://www.lazygranch.com/images/radio/loop4.jpg
http://www.lazygranch.com/images/radio/loop5.jpg
I have a similar set up that is 7ft on a side. That is about as large
as this single hub design can handle.

The thing with the Wellbrook loop (supposedly) is that as you make it
larger, the signal to noise ratio increases. It's not like a long wire
where the longer length boosts both the noise and the signal. Here is
what Wellbrook says about this:
-----
The large aperture of the ALA 100 improves the signal pickup to
optimise the signal to noise ratio and also reduces fading at HF, this
is a very important advantage compared to small active antennas
http://www.wellbrook.uk.com/ALA100.html
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I run the ala 100 with a loop about the size of a hoola (sp) hoop. That
is about as small as you should go.