Posted: Fri Jan 18, 2008 21:20 Post subject: WL-500gP wifi sensitivity mod :)
Becouse i'm realy disappointed about poor WL-500gP wifi sensitivity - here my mod to try make things litle better
All you need - move two capasitors (marked in red) in mini pci wifi card to other places (exactly how they are placed in broadcom reference board)
Nothing to say more, all you need - you can see in pics ...
here you can see where they are moved in moded wifi card
original places of capasitors in not moded wifi card
This is first post to this forum so please excuse any bad formatting.
I had a closer look at your suggested modications which by changing the capacitor positions, actually bypasses an extra amplifying stage based around U3 (SGA-8343Z RF transistor). This gave me the clue (which I really appreciate) to check why U3 was decreasing the signal and not increasing it.
What I found on my particular unit was that U3 , didn't have any DC power! I traced this back to R17. It can be seen at the bottom centre of your photos. On one side it had around 3 volts and on the other, it was something less than 0.2V. I don't know whether R17 is a SMD resistor or fuse but it wasn't providing any power.
I placed a shorting wire across R17 which was by no means an easy task since it is so small (not for the inexperienced!)
I'd include a photo if someone could show me how!
Hey presto, I had a bag of signal strength without having to change the capacitor positions i.e U3 was now working.
Therefore, it might be worthwhile before doing your modification to just check the voltages around R17 (very carefully). If it doesn't have 3V on both sides then I would suggest using the shorting wire across R17 and then checking how the signal strength is again. If it's OK, then I this avoids having to do your modification and retains the extra gain provided by U3.
I also checked a second WL500GP in use at my sisters and it too, had exactly the same problem as mine.
There's an amplifier on the mini PCI-card which is bypassed and this amplifier might or might not have power?
What about other brands?
I have 2 Premiums rather close to each other (10 meters without anything in between) but most of the time they don't run on 54 Mbit.
Do you think this will improve?
I'm interesting in doing this mod.
I have a bricked Premium, so I can try that one...., but I'd rather know a bit more...... _________________ Asus RT16N + OTRW
Kingston 4GB USB-disk 128 MB swap + 1.4GB ext3 on /opt + 2 GB ext3 on /mnt
Copperjet 1616 modem in ZipB-config
Asterisk, pixelserv & Pound running on router
Another Asus RT16N as WDS-bridge
I'm still learning how to drive forum editor so apologies for the bad formatting:
frater wrote: What about other brands?
The miniboard used in my WL500GP is ASUS branded so this would only be applicable to the ASUS models.
frater wrote: I have 2 Premiums rather close to each other (10 meters without anything in between) but most of the time they don't run on 54 Mbit.
Do you think this will improve?
It definitely improves the received signal strength but how that translates into improved speed is unfortunately not an exact answer (smoke and mirrors). It certainly gave me an improvement from 18MB/s to 36MB/s with exactly the same locations. It's also further complicated by the simplex nature of 802.11.
Ed wrote: So I did some research and used wl command's:
wl antdiv 0
wl txant 0
I thought that I may have overlooked a transistor acting as a power switch whilst manually tracing the miniboard for the power of U3 back to R17. I temporarily removed the shorting wire around R17 and executed the commands (with both 1 and 3 parameters) and still there was no power to U3. So therefore these commands, don't overcome the root cause of the U3 power loss.
Hi, I'm played todoay with R17 ... Yes , after powering U3 things looks better- rssi is nice , but noise is amplified too .. in dd-wrt I can see good signal quality percentage , but link speed is lower than with capasitors mod... (big noise level? ) . I can't understand how can this transistor work in original asus design - r17 is 62k resistor ...and resistors aroung U3 is 1 -2 K (collector -base , base - ground , and 10 ohm colector -power)
in attacment you can see network scan witch casitors mod and with R17 short ..
Yes, the noise would be amplified and perhaps your capacitor mod produces higher throughput. I was wondering whether R17 should have been 68 ohm and not 68Kohm (incorrect part loaded into SMD assembly unit?)
I originally tried your modifications and found it was somewhat difficult to access the capacitors. On my unit, once the shield cover was removed, there was an additional cross-brace that I had to cut away to provide better access - your photos don't show it, perhaps you also had to remove it? The R17 method has some advantages i.e. the modification is external to the shielded area and affects only one component instead of two.