Well, if you have an outdoor space, like a balcony, putting the antenna there may be an option.
I would have expected the first two antenna to work reasonably well - did you try rotating them?
Also, how far are you from the transmitters? I'm wondering if this is more of a multipath issue (and if so, an antenna with a very narrow beamwidth may be helpful) and not a signal strength issue. Also, what are you using for a tuner? Newer tuners handle multipath better than older ones.
Quality Assurance Manager, Ceton Corporation