I'm considering a an indoor flag or pennant type antenna for my apartment to supplement or replace the homebrewed loop I've used for the past couple of years. Some UK DXers have put up YouTube videos showing their indoor flags and pennants, and they seem to work well for MW - not sure about HF. These designs seem to be directional enough to null out competing stations on the same frequency. It'll be interesting to see whether it's directional enough to null out the worst local RFI as well.