Problems with SNR and a decent wifi connection

HKPiax

Commendable
Sep 28, 2016
3
0
1,510
Hi, I'm new and I don't know if this question belongs to this thread or this site in general, I say sorry in advance.

So, I have an issue: I can't get a decent wifi performance even though I should have everything in the right place.
My flat looks like this (it's not accurate, but you should get an idea).
I am not an expert in wifi, but I downloaded an instrument to analyze the wifi signal I get in my room and the result is this. I keep reading EVERYWHERE that a SNR which is >30 is really good, and mine is around 34.
STILL, in my room, the wifi is anything but good (even though my connection is stable at 10+ mbps):
sometimes it just stops working,
Netflix keeps stuttering every 5 minutes/the quality drops to 144p (same thing for YouTube),
it takes an eternity to load the router wizard (both in the old TP-Link I had, and in this new Netgear - which is really strange).
it takes an eternity to load websites in general.

For these reasons I tried and bought an extender, but, as you can see, the situation on the SNR level is not changed (tho the disconnections are fewer now - but Netflix and YouTube still don't work properly).

Having no knowledge whatsoever about this stuff, I am now completely discouraged and desperate, because I can't seem to find a solution, or even understand the cause!
Is it normal that the wifi strength is so low even after few meters? There's nothing blocking the way...
If the SNR is good, why I keep having a shitty wifi? (keep in mind that the moment I get closer to the router, everything starts working perfectly fine, 1080p and quick in loading.)

In my home we have a single router (FritzBox 3390) which covers THE ENTIRE HOUSE! (3 storey, much more than 3 obscenity removedblocks of concrete).
Could you guys please help me? I don't know what to do.
If you need any more details, I'm more than willing to give them to you.
 


My router and range extender are both on ch. 11, every other signal I can pick, as you can see in the screenshot, is on a different one.