Thinkpads Forum

I have a new-to-me T400 which came with a Intel 5100 WiFi card. (2-antenna diversity)

Apparently that series has the 5100 and 5300 Intel cards "whitelisted". Before I take it apart, does anyone know if the models that came with the 5100 still have 3 antenna wires so I can use the full functionality of the 5300 card if I upgrade to that?

Would it be worth the BIOS-hacking to go to the 6300 card instead?

I'm not so much worried about ultra-high speeds, but I like the potential range/reliability improvement that the 3-antenna cards with MIMO may provide.

One way to find out. Take the cover off the bottom, and that's all there is to it. If there's an unused wire, your answer is yes. If not, then you'll need to add one.

The 6300 is a newer card designed to be more energy efficient. I think it is pretty similar to the 5300 in terms of speed and range, if anything slightly better as it is newer. I don't think it's worth the hassle to upgrade to the 6300, but definitely consider the 5300 if you have the antennas. Better range, MIMO, draft N 450mbps vs 300mbps, and more reliable.


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hunterman223 wrote:One way to find out. Take the cover off the bottom, and that's all there is to it.

Actually, no. You need to remove the Palm Rest and the keyboard to get to the WiFi card/antenna terminals in a T400.
http://www-307.ibm.com/pc/support/site. ... 70069.html

Hmm. Always changing things aren't they. Well, it'll be a little more involved but not too difficult. It'll be a little more disappointing if the 3rd antenna isn't present though.


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What if you borrow one of the WWAN antennae?

WWAN antennae are not tuned for 2.4ghz. It could work to increase diversity and add a signal path, but it will not increase range much if at all.

Not to mention: since 802.11a and some variants of 802.11n use 5Ghz, not 2.4Ghz - Thinkpads (and laptops in general) must be using de-tuned antennas a lot, since AFAIK the laptops don't have separate antennas for those different wavelengths, and the WiFi cards themselves don't even seem to have separate antenna connectors for those frequency ranges either.

Unless there is some sort of built-in 5Ghz antennae on the cards themselves. Not exactly an ideal RF propagation scenario either.

(Re: borrowing WWAN antennae - some cellular signals are not far from WiFi in wavelength. IE the majority of the HSDPA/HSPA spectrum in the USA seems to be in the 1.7Ghz to 2.1Ghz range.)

Yeah, but running 1.7ghz over an antenna ideally suited to 2.4 and 5. its possible to tune an antenna to two different frequencies, it just has to have length that is a multiple of both.

But yeah, as i said, cellular tuned ants will *work* just not as ideally.

After you wrote that I just realized how convenient it is for the 2 main WiFi bands to be almost exactly 2x apart in frequency, from the antenna standpoint, yep.

There's a good chance that it is there. I just looked at the T400 system service parts page and there is no separate option for a separate 3rd antenna, and the diagram shows a 3 antenna setup for both WXGA and WXGA+.


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Good news, if true. Makes me a bit more motivated to check that out when I do the memory upgrade I'm planning, since I have to remove the keyboard/palmrest for that too I think.

I also want to change out the WiFi card before I get involved with Access Connections, since as I recall there's no easy way to migrate old profiles to a system with a different type of NIC. (When I've tried to do that in the past, all the profiles that were originally associated with a different hardware NIC became unusable.)