bosss7 | # 1 | 2013-11-29, 04:29 | Report

First time poster, long time lurker.

Just managed to bag myself a replacement for my busted N900.

Powered it up, re-set everything to defaults and started using with WIFI only.

For the first few hours everything was fine but after maybe 8 hours, the phone stopped picking up WIFI signals. At first I thought I was out of range but then I noticed that previous hotspots I connected to stopped working also. Once I got home, I discovered that WIFI still works on the phone, but I have to be very close (about 3 meters away) from the router for it to work.

I already tried re-flashing multiple times, as well as replacing the entire back assembly which houses the antennas and what looks like some sort of transmission coils.

One thing I did do the day before although I'm not sure if it's related, is dropping a Softbank (Japanese) SIM card into the phone to see if it would work, which it did. I thought maybe the SIM card overwrote some settings which caused very weak reception, but the time between the SIM card going in and the weak WIFI was about 8 hours.

If this phone has weak WIFI, it's potentially useless for anything, so if anyone has any suggestions, I would greatly appreciate it.

Thanks!

pichlo | # 2 | 2013-11-29, 09:31 | Report

You can pick up the signal, so the electronics are working, but something is weakening the signal. Loose contact between the board and the antenna? Dirt or moisture on the PCB? I would try opening it up, cleaning it (which may be a good idea anyway, a second-hand device is bound to be full of fluff and dust) and perhaps spring up the antenna contacts. With no guarantee of success.

bosss7 | # 3 | 2013-11-29, 11:35 | Report

I like the optimism of the last bit.

I'll give that one a shot. I guess I didn't really clean it all that well the first time around. Cheers.

Mitrigol | # 4 | 2013-11-29, 12:15 | Report

You can configure wifi power management in connection settings.

It is on auto by default, try to set it at 100mw manually and see what happens (low power mode is 10mw only)

EDIT: You can find the setting under:

phone settings/internet connections/connections/*connection name*/edit/next/next/next/advanced/other/WLAN transmission power

If it is already at 100, you can try to change to 10, then save, exit and reopen to modify back to 100. It is sometime usefull to do this. Don't ask why

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Last edited by Mitrigol; 2013-11-29 at 12:37.

bosss7 | # 5 | 2013-12-02, 01:28 | Report

I'm now at a loss. Cleaned it out but the same problem persists. Also the power output is set to maximum globally through iwconfig, with power management off.

Anyone have any other suggestions? Would really appreciate it.

Also tried two other antennas so that's not the issue. Contact are nice and clean, as is the PCB.

pichlo | # 6 | 2013-12-02, 07:14 | Report

The point with the contact springs was to bend (I used the word 'spring'; sory if that confused you, English is not my first language) them up a bit to achieve a better contact with the antenna. Carefully, lest they rip off from the PCB. I am only speaking from experience: I had a similar lack of sensitivity problem while I was swapping a housing and was temporarily with no antenna.

If you've tried that then I am equally at a loss, sorry.

Kossuth | # 7 | 2013-12-02, 09:27 | Report

Have you tried to set the power management on and the transmit power down and see if you can get the reception even worse and see if the settings have any effect on the reception. If this does not affect the performance in any way, could it be possible that the power management off and 100mW settings are actually not in effect and the WLAN defaults to the worse settings somehow. I have no idea how, but just thinking that you could check that your settings are getting through.

bosss7 | # 8 | 2013-12-02, 14:47 | Report

Thanks for the advice so far. Greatly appreciated.

No worries pichlo. English is not my first language either, and your explanation was not confusing at all. I did try to bend the pins up a bit more but to no avail. May try that again though as I might not have bent the damn things up enough.

I also tried lowering the transmit power values bit by bit through iwconfig, until I had them all the way down to 1dBm, which did not make a lick of difference unfortunately. Was using the "iwconfig wlan0 txpower xx" command, while connected to the AP. Will try again though at home.

On a side note, is it possible that the WLAN chip itself might have been slightly damaged for whatever reason, resulting in a power drain of some sort? Maybe even a short circuit somewhere along the antenna lines?

I also noticed that when I was connected, even with the signal strength at maximum (for when I am standing next to the AP), the noise margin iwconfig reports is at -113. Is that normal?

Thanks heaps for the help so far. I'll persist!

Kossuth | # 9 | 2013-12-02, 18:48 | Report

From upstairs about six meters from cheap buffalo router running dd-wrt. Weak reception normally through walls and floor:
Near the router good reception distance one meter:

N900 touching the router:

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Last edited by Kossuth; 2013-12-03 at 05:51. Reason: Less clutter

pichlo | # 10 | 2013-12-02, 19:18 | Report

I got similar results as Kossuth except I'd gone even lower down:
How did you manage to get -113 dBm noise? I envy you.