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-   Nokia N900 (https://talk.maemo.org/forumdisplay.php?f=44)
-   -   Weak WIFI reception (https://talk.maemo.org/showthread.php?t=91884)

bosss7 2013-12-02 23:58

Re: Weak WIFI reception
 
I'll post some stats later on....

bosss7 2013-12-03 01:03

Re: Weak WIFI reception
 
Okay. Stats be thus:

1) Touching the Access Point:
Code:

Bit Rate=9 Mb/s Tx-Power=20 dBm
Retry min limit:7 RTS thr:off Fragment thr=2352 B

Power Management:off
Link Quality=86/100 Signal level:-39 dBm Noise level=-102 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

2) 1 meter away from the AP
Code:

Bit Rate=9 Mb/s Tx-Power=20 dBm
Retry min limit:7 RTS thr:off Fragment thr=2352 B

Power Management:off
Link Quality=40/100 Signal level:-69 dBm Noise level=-98 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

3) About 3 meters directly above the AP on the second floor of the house. NOTE: The floors in a Japanese house are paper-thin, so there wasn't really any obstruction to speak of:
Code:

Bit Rate=1 Mb/s Tx-Power=20 dBm
Retry min limit:7 RTS thr:off Fragment thr=2352 B

Power Management:off
Link Quality=7/100 Signal level:-90 dBm Noise level=-105 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

How bizarre, how bizarre....

pichlo 2013-12-03 09:08

Re: Weak WIFI reception
 
My router is in the garage and I got 39/100 in the room just above it, perhaps 2 metres from the router (the floor void thickness plus my height). By the sound of it, the English houses are built to the Japanese model (or at least mine is :)), with paper-thin floors. Curiously, moving about 2 m to the left increased the signal to 46/100, moving even a bit more away to 68/100. Must be something to do with the directional properties of the router's antenna: better sideways than up and down.

Back to the topic, your numbers confirm what we already know: either your router's signal level has dropped or your phone's receiver has reduced sensitivity for some reason. Having tested with other WiFi hotspots, as mentioned in the first post, rules out the former.

You've mentioned having replaced the housing. Can you confirm that the replacement has indeed good working antennas? My experience with similarly reduced sensitivity comes exactly from my replacing the housing exercise. This picture clearly shows what the antennas should and should not look like (note the golden pads):

http://talk.maemo.org/attachment.php...9&d=1385258851

bosss7 2013-12-03 09:24

Re: Weak WIFI reception
 
1 Attachment(s)
Thanks for the response.

The antenna does indeed have gold pads. Attached is an image of one of them.

The pads are all in roughly the same shape.

EDIT:
Quick question. What the hell are those two silver square(ish) things on the left and right of the inside of the back cover? They look some sort of transmitter coils. Both have two pins on them.

pichlo 2013-12-03 09:47

Re: Weak WIFI reception
 
Quote:

Originally Posted by bosss7 (Post 1392057)
Quick question. What the hell are those two silver square(ish) things on the left and right of the inside of the back cover? They look some sort of transmitter coils. Both have two pins on them.

You mean like in this picture? (Please ignore the arrows, they belong to a different topic where the picture comes from)...

http://talk.maemo.org/attachment.php...0&d=1385258897

Those are the speakers.

Your antenna looks OK. Sorry, I am out of ideas :(

bosss7 2013-12-03 10:07

Re: Weak WIFI reception
 
Ah of course! Thanks for clearing that up.

Thanks for you effort by the way.

I'll keep trying to fix this. I'm also thinking it may be some sort of grounding issue inside the phone so I'll do some tests later this week and hopefully I can solve this.

Cheers!

Estel 2013-12-04 16:44

Re: Weak WIFI reception
 
Quote:

Originally Posted by pichlo (Post 1392055)
My router is in the garage and I got 39/100 in the room just above it, perhaps 2 metres from the router (the floor void thickness plus my height). By the sound of it, the English houses are built to the Japanese model (or at least mine is :)), with paper-thin floors. Curiously, moving about 2 m to the left increased the signal to 46/100, moving even a bit more away to 68/100. Must be something to do with the directional properties of the router's antenna: better sideways than up and down.

That's pretty normal - regular omni-directional monopole (aka stick) antennas have, in fact, radiation pattern simillar to doughtnut mixed with disc:
http://www.antenna-theory.com/antenn...edMonopole.jpg

...wchich results in worst signal directly above or under antenna. In your example, you were standing in the "blue" depression, shown in picture. (z-axis is your antenna - that is, signal is worst where antenna tip points).

Of course, alligning antenna stick horizontaly instead of verticaly, would result in better reception at higher (and lower) floors, but worse to the sides (but only to the two sides - the one that antenna is pointing at, and the opposite one).

/Estel

bosss7 2013-12-05 00:12

Re: Weak WIFI reception
 
Ok, I think maybe I know what is wrong now but if that is indeed the case, I have no idea how to fix it.

I have a bad feeling that it is indeed a grounding issue on the mainboard somewhere. I have been noticing that each time I hold the N900, I seem to get a very slight tingle through my fingertips (and it ain't from the excitement of finally having anN900 again :) )

The second my hands move, it stops. I understand that there's a slight electrical charge moving through the screen but the keyboard?

Maybe that's what's causing the weakness in the wifi? A kind of signal bleed maybe?

Correct me if I'm wrong, which I probably am.

Kossuth 2013-12-05 05:25

Re: Weak WIFI reception
 
Sounds strange and I can't say that you dont feel it, but you only have 3,7V voltage on your phone, and I suspect that it is hardly enough to push any current trough dry skin. On the other hand sensitivity to electricity varies a lot form person to person.

You can test it yourself, by shorting the the contacts of removed battery with your finger. I just tested with 12V car battery and wet fingers and couldn't feel anything. You dont have any other potential in your phone as it is not connected to any outside antenna or powersupply.

Basically I have always thought that grounding issues cause static and signal errors when you connect two appliances that are in different potential and that causes the current to flow from higher potential to the lower potentia for example from a ungrounded television to grounded DVR or vice-versa.

If you want to research this grounding issue more, you should check the current that your phone is using, with the bq27200.sh script and see if there is actually a current draining from the battery. I'm not sure where in the circuitry the ampere meter is located in N900, but I think it should capture most of the current that leaves the battery.

bosss7 2013-12-05 08:12

Re: Weak WIFI reception
 
Hey Kossuth,

Thanks for the info. I'll give this a go in the next day or so.

Much appreciated! :)


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