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jim_nospam_beasley@yahoo.com
02-24-08, 12:13 AM
When I have my laptop in the same room with my access point, I can't
connect my laptop (Dell D410 with 802.11 b/g using WPA). When I put a
couple of walls between me and the AP, I can connect. This is very
consistent now.

This is exactly backward from what I would expect. Like the signal is
too strong to connect.

I have other devices (three right now) in the room connecting with the
AP without trouble. They use the LinkSys WUSB54G. Access Point is a
WRT54GS.

As far as I know, I have the latest drivers installed for the laptop,
which uses a Dell Wireless 1470 Dual Band WLAN Mini-PCI Card. The
driver is version 4.100.15.5.

What's up with the laptop?

Thanks in advance for nay ideas.

Jim

Jeff Liebermann
02-24-08, 12:48 AM
jim_nospam_beasley@yahoo.com hath wroth:

>When I have my laptop in the same room with my access point, I can't
>connect my laptop (Dell D410 with 802.11 b/g using WPA). When I put a
>couple of walls between me and the AP, I can connect. This is very
>consistent now.
>
>This is exactly backward from what I would expect. Like the signal is
>too strong to connect.
>
>I have other devices (three right now) in the room connecting with the
>AP without trouble. They use the LinkSys WUSB54G. Access Point is a
>WRT54GS.
>
>As far as I know, I have the latest drivers installed for the laptop,
>which uses a Dell Wireless 1470 Dual Band WLAN Mini-PCI Card. The
>driver is version 4.100.15.5.
>
>What's up with the laptop?

The Dell 1470 wireless card in your Dell D410 probably has a problem
with the receiver AGC (automatic gain control). Todays Wi-Fi chips
are all digital. They digitize the RF as early in the receiver chain
as possible. The A/D (analog to digital) converter involved needs the
widest possible dynamic range in order to properly deal with both weak
and strong signals without overloading. My guess(tm) is the AGC gain
control circuit that does this has failed.

A clue that my guess(tm) is correct is to monitor the signal strength
with your laptops unspecified operating system. If I'm right, you'll
have roughly the same receive signal level, no matter whether you're
right next to the access point, or in the next room. If it's
constant, the AGC is not working. However, if the receiver uses the
BER (bit error rate) to calculate the corresponding signal strength,
then the readings will instead be weird (jump from high to low and
back and forth) instead of stuck at one value.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

jim_nospam_beasley@yahoo.com
03-29-08, 03:41 AM
Jeff,

I think you are right. I replaced the Mini PCI card this week, and it
works fine now.