Thanks for your reply. This probably is way way more than what I or most people wanna know about wifi, but I found my question to academically curious, So let me share details of my wifi set up and what I was trying to do, if possible...LOL
I understand how wifi radios works and travels, directional and omni direction antennas, etc..from google search.
I live on 15th floor of condo building, condo is about 500sqft(this is in Asia), Since I got fast fiber 25mbps internet, friends around me wanna share at cheapest way possible.
(BTW if this was my house of several floors, etc, and I am willing to spend lotta money for WAP, repeaters/extenders, etc..maybe what I am asking can be done.)
Back to my layout.
So main router is in middle of condo, Condos next to me on same floor, even two doors away, can get 3-4 bars, can can get 5-10mbps.
But condos above(16th), or below(14th), only get 1-2bars, barely get internet, maybe at less than 1mbps.
Mind you above/below condos are actually closer in distance than, say, same floor condos, two doors away.
So same floor condos get better wifi cus on same floor, only thru my door and their doors. And I get that,
BUT the mystery is even if I stick out router out the window and turn router and antenna in all possible ways, above/below condos get no better than 1-2 bars still. It's like nothing changed.
This was a surprise cus I thought wifi travels better thru open air than doors.
Just imagine, open window and holding out router in free air...
Ok, now powerline extenders, etc...(I am not 100% sure) but powerline must be within my condo?
So I got a long extension cord, plugged in extender, (again) stuck it out the window, still only 1-2 bars.
Even threw outlet cord above/below condos (by now extender is far from router in my condo), now extender is too far from router thus not work, 1-2 bars from router is better than extender.
BTW those extenders work across maybe one more condo distance, so not reach too far. Better than nothing but IMHO not work too good.
(Funny, plugged in extender next to router. Wifi from extender is stronger than router.. Same floor next condos get 4-5 bars wifi extender but only 3-4 bars from router.. Now that don;t make sense at all..????
Back to wifi radio waves...I understand horizontal spread, but when held 90 degree than same horizontal now become vertical wifi spread? thus should reach above/below condos better than same floor condos?
Anyway, just a curios question.