Channel 4 in the St. Louis area is broadcasted in UHF channel 4.1 and in VHF channel 4. I have an indoor antenna now and the TV picture is super good in the UHF channel 4.1 and not so good in the VHF channel 4. So I think the 4221 would probably be OK. However, I am now checking out the Terrestrial DB8 antenna. Does anyone have any experience with this antenna? My mission is to bring in only UHF digitals for backup when the dish antenna has thunderstorm problems. I am planning on the OTA running to three 722s and one 322.
No, channel 4 digital is not on UHF 4.1 It is at UHF 56. Channel 56 is mapped by your tuner so it appears as 4.1, the stations use this "virtual mapping" so they can retain their identity, since they have put a lot of marketing into being "channel 4".
Rather than a DB8 you should get the CM4228 which is a better antenna at less money (although you may have to dismantle it to get it into your attic). But either will probably be an overkill. The CM4221 should be OK