WL-500gP wifi sensitivity mod :)

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RolF
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Joined: 28 Sep 2007
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Location: CCCP

PostPosted: Fri Jan 18, 2008 21:20    Post subject: WL-500gP wifi sensitivity mod :) Reply with quote
Becouse i'm realy disappointed about poor WL-500gP wifi sensitivity - here my mod to try make things litle better Very Happy
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) Smile
Nothing to say more, all you need - you can see in pics ...

BR
R.



moded.JPG
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here you can see where they are moved in moded wifi card
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moded.JPG



original.JPG
 Description:
original places of capasitors in not moded wifi card
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original.JPG


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RolF
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Joined: 28 Sep 2007
Posts: 349
Location: CCCP

PostPosted: Fri Jan 18, 2008 21:22    Post subject: Reply with quote
And here you can see sensitivity tests before ant after mod in same environment ...


R.



after.gif
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sensitivity of moded wifi card
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after.gif



before.gif
 Description:
sensitivity of not moded wifi card
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before.gif


slimey
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Joined: 14 Feb 2007
Posts: 330
Location: Texas

PostPosted: Fri Jan 18, 2008 23:06    Post subject: Reply with quote
nice, how did you figure this?
RolF
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PostPosted: Fri Jan 18, 2008 23:22    Post subject: Reply with quote
as you can see in attachment - all this crap ,that i unlinked with capasitors - are even not soldered in broadcom reference board :)

R.



reference.jpg
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reference.jpg


a9988cd
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Joined: 16 Mar 2007
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Location: Taipei,Taiwan

PostPosted: Sat Jan 19, 2008 4:54    Post subject: Reply with quote
Very interested,transmitting power will be affected?
RolF
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PostPosted: Sat Jan 19, 2008 11:24    Post subject: Reply with quote
a9988cd wrote:
Very interested,transmitting power will be affected?


no, if you take a look in SIGe 2521A60 datasheet - this is only RX line.

R.
Trailblazer
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Joined: 23 Nov 2007
Posts: 44

PostPosted: Tue Jan 22, 2008 20:07    Post subject: Thanks! Reply with quote
For the great mod!
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Alan
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Joined: 27 Jan 2008
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PostPosted: Sun Jan 27, 2008 13:30    Post subject: Reply with quote
Hello Rolf,


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.



Alan
frater
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PostPosted: Sun Jan 27, 2008 13:54    Post subject: Reply with quote
So.....

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......

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Dr.Ed
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PostPosted: Sun Jan 27, 2008 14:15    Post subject: Reply with quote
Before soldering try this one:

I'm getting also a bad Wi-Fi signal. Connection drops from time to time.

So I did some research and used wl command's:

wl antdiv 0
wl txant 0

gives same bad signal, changing numbers into 1 or 3 gives me the best (+35/40Db) stronger signal!

I'm a bit of a Linux noob so i have a question: How do I save the above commands in my NVRAM?


Ed

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Alan
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PostPosted: Sun Jan 27, 2008 14:58    Post subject: Reply with quote
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.


Alan
Alan
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PostPosted: Sun Jan 27, 2008 23:10    Post subject: Reply with quote
Ed wrote:
So I did some research and used wl command's:

wl antdiv 0
wl txant 0


Ed,

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.


Alan
RolF
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Joined: 28 Sep 2007
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Location: CCCP

PostPosted: Sun Jan 27, 2008 23:39    Post subject: Reply with quote
@Alan

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 ..



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r17short.gif



capasitors.gif
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capasitors.gif


Alan
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Joined: 27 Jan 2008
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PostPosted: Mon Jan 28, 2008 1:19    Post subject: Reply with quote
Rolf,


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.

I'm new to this forum. How did you include your photos? The last one points to:
http://www.dd-wrt.com/phpBB2/files/capasitors_130.gif
i.e. on the DD-WRT server. In the FAQ it suggests photos have to be hosted on an external server.



Alan
Alan
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Joined: 27 Jan 2008
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PostPosted: Mon Jan 28, 2008 1:22    Post subject: Reply with quote
Rolf,

Whoops, my previous post should have said 62 ohms/62Kohm (not 68/68Kohms)


Alan
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