Is your glass door anti-reflection/K-coated by chance? Thermal glass is usually in the microns range with WiFi in the centimeters range but certain coats are very close to the latter.

I have no idea, but it does work better with the door open and just the screen door in between. Anti wifi glass I guess. I take the console out on the deck anyway, problem solved.

Then it probably coated. Its not so much anti-wifi as it is that there are certain metal bonds that can be used that are intended to keep heat in and other things out, but will have properties that end up interfering with transmission in the long wavelength ranges where wifi lives. Newer panels tend to be better made to avoid this problem.

Makes sense. My whole house seems anti wifi :/ I couldn't get the wiiU to stay connected to the router 1 floor down (and 20 meters sideways) and had to use my laptop as a wifi hotspot to bridge the signal. Later I moved the router to the loft above the living room, stealing a cable outlet there, which works better for the living room. But now I have sucky internet on the ground floor where my game room is. Takes forever to download updates there. It's mainly a wooden house, concrete/stone ground floor, standard drywall, open floor plan. I don't get why wifi sucks so much.

Whats the frequency band on your wifi and whats the power of the signal being output (or are you running stock firmware)? It may just be a weak router or the signal is low-power and the materials of your house are attenuating it so much that it drops off really quickly. In general any and all material is going to affect wifi signals as they are huge wavelengths (orders of centimeters) but if you have a strong source it will usually be able to overcome attenuation from destructive interference.

If you're running stock firmware I'd suggest to stahp eet and get Tomato or some other better firmware to install on your router. That way you will have full control over the signal output, the wavelength, and the power of your broadcast. Every router can do more than stock allows but you do have to be careful to not turn the output so high as to cause the thing to overheat and burn out. 

Does it count as a wifi hotspot for the vita? Then yes.

Your data is going to go through the roof though.

Absolutely! Remote play uses about 5 Mbits per second. That amounts to about 1 GB for a 30 minute gaming session.

Not sure how good latency is on a 3G network, though. Especially with the added latency of having to go through the phone and its software.

the problem is the walls.
if no wall, it reached more than 12 meters.

The standard 2.4ghz I guess 11B/G/N Mixed and it's set to auto select the channel. (Forcing it to use channel 1 or 11 didn't help) I used a bridged Linksys router before but it wasn't much of a boost. With the linksys router I kept getting 30sec to 60sec internet outages all the time while my laptop kept claiming it was getting 5 bars. My ISP didn't support the extra router and said to unbridge the modem since there was probably some conflict between the two. So now I'm back to just the cable wifi modem supplied by Rogers, Hitron tech CGN2-ROG. I have no idea how to change the stock firmware or if my isp overlords would even allow that :/