[Tfug] WiFi hardware hacking in my new Dell 1525 laptop

[Jim March]

I've almost doubled my WiFi range via an Intel 4965AGN swapout.  Read on for
details :).

In our last chapter of this saga, we saw how the stock Broadcom Dell WiFi
card (1395) stank.  Swapping out a slightly older (1390) mini-PCI-express
card helped a bit.  The computer itself internally has three
mini-PCI-express slots.

I thought that all three internal slots would support WiFi cards but it
turns out only the far right slot will take WiFi.  Putting a WiFi card
(Broadcom or Intel) in any other slot leads to Ubuntu Hardy not recognizing
it at all (no appearance under lspci or anything else).

I was able to score an Intel 4965AGN mini-PCI-express card at SWS for $45.
It's something they normally stock and they have one left as of yesterday.
This is the version with full WiFi (B/G/N) but without onboard bluetooth
support.

This.  Card.  Rocks.

Totally FOSS driver support and was instantly recognized and running.
Performance is unreal - it's pulling in signals I've never seen before in
the locations I usually hang at.  It's able to lock onto SSIDs showing 25%
or less signal strength and maintain connection.

THE THIRD ANTENNA SAGA

The 4965 has three antenna jacks labeled 1 3 2 - in that order.  The deal
is, you have to connect standard WiFi antenna leads to the outer two (1 and
2) ports.  #3 is optional - it doesn't affect the card's ability to pull in
distant signals.  It does affect speed when you're using a class N router.
With the third antenna jack in use, speed can rise from a max of 150mbs to
300, as long as everything else is copacetic.  But if you don't hook that up
right away, you'll still get major range and performance benefits out of
this N-class device.

Right now, I've got my two original WiFi leads on 1 and 2 and I stuck the
EVDO blue antenna lead on 3.  It's likely "not quite right" (a real RF
hacker would likely cringe) but what the hell.  I'll score another antenna
later from a junked machine I have access to and run it funky somehow.
Meanwhile it's a crapshoot as to whether or not I'd see 300mbs out of an
N-Class router but since I seldom have access to one, I'm not sweating it.

A WARNING:

According to the SWS guys, this card only works on laptops that are based on
Intel chipsets.  My Dell has a low-end Intel dual-core CPU ("Pentium
dual-core", not the higher end "core duo" series) and an Intel 965 ("X3100")
video chipset.  Allegedly, you can't use this 4965 critter if you have an
AMD CPU or your rig otherwise strays too far from the Intel family tree.  I
haven't been able to confirm that with other sources but...knowing Intel it
makes sense.  I've seen references to the 4965 being tied to the "Centrino
chipset" but it's not explicitly stated as a limit.

MEANWHILE, WTF IS UP WITH MY SLOTS?

I have three mini-PCI-express internal slots labeled "UBG", "WWLAN" and
"WLAN".  The stock Broadcom card (and now the Intel) was at the far right
(WLAN).  When I put the Intel card in the middle or left slots, it failed to
list in lcpci.  Several clues tell me that the "UBG" slot is for
EVDO/cell-modems (Verizon, Sprint, etc.) while "WWLAN" most often turns up
when HSDPA is discussed (per google searches).

Does anybody have a clue how (or even why?) Dell limited each slot as to
what it does, or at least managed to block additional WiFi cards?  I went so
far as to put the Broadcom/1390 card that worked fine in the far right into
the middle and left slots and lspci couldn't find it.  I was hoping to score
an Atheros card down the road and with that in another slot, use that as
"transmit" (broadcasting my cellmodem signal from my USB-based cell network
adapter).  That idea appears to be DOA.

Does anybody know if the Intel 4965 can be used as a WiFi broadcast device?
I'm thinking "probably"...?

Jim
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