I used a coax fed basic homemade fm receiving antenna since it seemed to be the easiest design for what I had laying around the house. I actually found a video on youtube about how to put it all together.
https://www.youtube.com/watch?v=KjTshXYsRss I have a lot of power lines surrounding my house, so this seemed like a good idea. The coax feed line may have been a bit long (about 25 feet), but it works. The dipole portion of the antenna was a 10' piece of RG-58 I had laying around, five feet on each side of the feed line. The instructions that came with the ANC-4 say to keep the dipole as small as possible, about 6 feet on either side, if I remember correctly. I just took it a step further and made it a bit smaller. Also, when searching for the resting spot for the noise sensing antenna, it's important not to place it at such a height that it will pick up the same signal that you want to listen to. Mine ended up right outside the window of my shack, in plain view of all the power lines and my neighbor's bedroom window where she keeps her noisy tv, so most of that 25' of coax feed really just got zip tied up. So, just in view of the noise source is a good idea; ya don't wanna null out the good stuff. It took a good hour or so of trying to find the right placement, it's worth it to be patient.