Re: Weak WIFI reception
 

@Estel,
I know, I was a member of a radio club in my early teens :) And I had a year of electromagnetic field theory at the Uni. But I did not want to over-complicate it with technical details. Moreover, although the router's antenna looks like a simple stick dipole, I don't know what's inside. Maybe some coil or something to change the directional properties, who knows?

@Kossuth,
Ineffective grounding may well cause issues in the RF area. RF is a sensitive beast, grounding is about more than just currents between two points. The higher up you go in frequency the more complex the issue becomes, which is why not every Jim and Mary can design high frequency RF circuits.

On the tingling issue and safe voltages, the most powerful transmitter in the phone is GSM with a peak power output of 2W. I do not know the GSM antenna's impedance, but I don't think that 50Ω would be too far-fetched. Hugely simplified, V = √(P*R), meaning the GSM trasmitter pumps at least √(2*50) = 10V to the antenna at peak power. (For WiFi the figure is much lower, only about 2.2V.)

There is no electric contact from inside the phone to the surface that one could touch, so any sensation must be either induced or mechanical vibrations confused for electric current. I have not noticed any tingling so I cannot tell.

@bosss7,
If you suspect grounding issues then you can try to bend the ground plane springs up to make a better contact with the PCB. You can see four of them clearly in my last picture, plus one highlighted with the blue arrow which is the FM transmitter antenna contact. However if grounding were the problem then I would expect all RF to suffer: WiFi, BT, GPS and GSM.

Re: Weak WIFI reception
 

@pichlo,
You are absolutely right that the grounding is very important in the RF-domain and even tiny variations in the impedance caused by for example oxidation in contact can dramatically reduce the performance of the circuitry. My EE degree is from heavier electricity (<1000V) so when I have to deal with faulty grounding it is always potentially deadly, so I tend to see the grounding stuff from that point of view and was sceptical about the fact there could be high enough voltage for average user to feel. On the other hand, the frame around the screen is metal and nice oval shape, so theoretically you could induce some current to it, and if there would be crack in it, there could be some voltage over the opening, maybe only millivolts though. There are ofcource other parts that could suffer from millivolt level noise that could alter their performance.


@bosss7,
I'm with pichlo on the matter that the most likely cause for your problem and also the easiest to repair, would be the contacts between the board and the antenna, so make sure you check them for good contact and they are clean. Altough this has been mentioned to you more than once, so I feel we start to sound like a broken record ;-)