I bought this as a more modern, and smaller, replacement for my ancient portable set-top aerial (made from bits of bent wire!). With my old set-top aerial I got slight interference on all analogue TV channels (especially bad with Channel 5), but good digital TV pictures.
With this magic wand it was dreadful - the analogue TV pictures were unwatchable for the interference, and the digital channels had constant "break-up" (pixellation).
So I binned the magic wand aerial and went back to the old wire set-top one!
I'm in a good signal strength area (obviously, if I get channel 5 on a set-top aerial) so God knows what this aerial is like in a poor reception area! (...and I tried it with both batteries and a 12Vdc power supply).