It works! But...
It works - typically these add ons are not a good idea, but it actually works well. It has extremely narrow bandwidth, so you basically have to decide what frequency you want to be on and that's it. You'd be lucky to get a kc or two either side. A tuner won't help much either. If you have a really extensive ground radial system you might be able to get a little more bandwidth, but not much. It'll receive great across the band and even out of band.