Not just concrete, those floors should have alot of steel mesh or rebar in them.
They're basicly shields for radio waves.
Is there any way to hang your router out the window or can you get it near the window?
I tried to put the router near a window.. but the window is at the complete opposite. So I got worst result put the router near my window.
But today I bring my laptop for do some test.
I got 100% in my appartment.
55% one floor above in the stairway.
25% 2 floors above in the stairway.
Other side of the door (in from of the starway / 2 floors above) 0-5%
I got drop here... 10-20 meters before I get where I want...
I estimate I need something like at least 3-4 times 802.11g range.
Did 802.11n works better around concrete and steel mesh... ?
I receive an WRT310N (2 intern antennas) today.
He should be 2 times better than WRT54GX2... but turn out.. my WRT54GX2 beat the WRT310N on the range.
My WRT310N was about 2 times better on the range...
I return it tomorrow.
I think about an WRT300N right now.
He should 2 times better than WRT54GX2.
But if I buy this one I can't return it if he give me bad result...
I doubt you will get a signal form your appt. up to the roof through the walls/ceilings. If you want to use your laptop outside, you can get a USB Cellular modem that will work with your cell phone plan (if you have one). That is a pretty expensive thing though and limits you to how much you can browse before you get hit with data charges.
Have you actually tried your laptop outside? The sun will probably wash out your screen so much you won't be able to read anything.