The signal strengths are very strong at your location.
Do Not use any type or kind of amplifier or amplified antenna.
The amplifier will over load and be the cause bad reception and no reception.
Do not use a omnidirectional type antenna , the strong multi-path signal reflections bouncing allaround will be received by the omnidirectional antenna and be the cause of bad reception or no reception.
Indoor and attic Are Not reception friendly environments and Never Will Be a reception friendly environment.
If using a indoor type antenna , use a antenna such as the Terk HDTVi (not HDTVa) antenna.
If using a indoor type antenna Do Not use a antenna that has any type or kind of indoor antenna that has a control knob such as and not limited to the So Called fine tuning control.
A indoor antenna must be a plain Jane indoor antenna.
If you have a Plain Jane indoor type antenna such as the Terk HDTVi indoor antenna or a rods and loop type antenna.
Then put the antenna in/at a window or patio/balcony window that faces the ~ South West ~.
Aim the antenna at about 200 degree magnetic compass direction.
Here is how to aim indoor and outdoor antennas ,
www.kyes.com/antenna/pointing/pointing.html
If a coax must be run through the rooms of your condo unit to get from the antenna to the Tv then So Be It.
---------------
Or can install a ANT751 antenna above the roof in such a manner that reception is not , obstructed , impeded , blocked , by the roof and building in the directions of , South West , South , South East , North East , North West.
Aim the ANT751 antenna at about 200 degree magnetic compass direction.
Do Not use / install any type or kind of antenna system amplifier.