I own one, and it's pretty sensitive. About on a par with my 2013 LG tv sets tuner, which is really good. Add an external harddrive, and it's a dvr. Only catch is you have to use the Sling App with it, along with a Sling Tv account (you do NOT have to subscribe and pay anything for this account!) and then your local channels appear in the SlingTv guide.
I thought you had one of the Air TV dongles at one time, maybe for a Wally. Guess I'm thinking of someone else.
I do have one of the Air TV dual tuners on my Wally and it does not do well tuning in my local stations about 18 miles away. Just curious about this box.