Well, I wouldn't take that tech's word as on target. That web page looks like it's at least partially based off of a FCC listing, but it's reasonably accurate.
A couple of comments here - you won't hear very much in the broadcast 11 meter band right now. Most broadcasters aren't using it, even though at times propagation might support it. The problem is that due to the erratic solar cycle, sometimes it would work as a long distance to other countries, others not.
There are portions of the CB band (channels 16, and in some areas 36-40) as well as the amateur 10 meter band, where a mode called SSB (or single side band) is used, and I don't believe the Grundig is set up to handle that. It will sound like a distorted Donald Duck. There are also numerous digital modes and even FM (29.60 and 29.62- 29.68) that the Grundig also cannot handle. There are a few hams doing AM in that band, and when propagation is good enough, no doubt with a good enough antenna, you might hear them if they're on.
The problem with hearing traffic above, say 21 Mhz or so on a regular basis has to do with propagation. Quite apart from the solar cycle, there's another factor involved. We're slowly but surely heading into winter, when higher frequencies don't propagate quite as well. If you reviewed that AE4RV website I gave in another message you understand why - at this season, we're tilted slightly away from the sun, so we don't quite get the same amount of radiation as we do during the summer, when we're tilted slightly towards it. That's not to say that it doesn't work - 15 meter hams wouldn't be able to work DX during the winter - they do, but it's not quite as regular nor as easy.
A good regular indicator of possible higher propagation would be the 17 Mhz broadcast area - if you start hearing a lot of stations here, time to move up the bands a bit. If not, drop back to 15 Mhz (19 Meters). Learn the bands well, and in time you will be able to spot openings when they occur. But it takes time and patience
Mike