Tech Support > Computer Hardware > Laptops/Notebooks > external WIFI antenna?
external WIFI antenna?
Posted by none on October 19th, 2007


Decided to take my IBM Thinkpad T41 apart to upgrade a few things.
Noticed the WIFI card has TWO antenna jacks, internal and EXTERNAL!
Followed the 'external' antenna wire to find it ending up by the USB
ports. Upon close examination noticed just left of the USB ports is a
small vertical rectangular opening with what APPEARS to be, an antenna
symbol. Hmmm.

I have a radio hobby and have seen a lot of antenna jacks but they are
all HF, VHF, UHF types. Being the WLAN uses frequencies above these (it
transmits at 2.4GHz) that must be the reason for the different jack.
Thing is, where does one find an external antenna with a rectangular
plug? I have a couple of WIFI antennas for 2.4GHz but they do not have
rectangular antenna plugs, they're coaxial type.

So how does one use an external antenna with one of these rectangular
jacks?

Thanks


Posted by Bigguy on October 19th, 2007


none wrote:

The miniPCI wireless card has two jacks marked Main + Aux (Grey + Black
cables)...

Is it an IBM wireless card?

Guy

Posted by E. F. on October 19th, 2007


You may want to post your question on alt.internet.wireless. Some of
the folks there are handy with hardware.


Posted by none on October 19th, 2007


Yep, I'm sure. In fact have two T41's and each has a different WLAN
card. Both have internal and external antenna jacks with coax from each
(gray and black as you mentioned). One is an Intel, one Cisco.

The image by the 'port' :

_|_
|__|
_|_
|__|
|
_|_

It doesn't look like the outdoor TV antenna as most would recognize as
an antenna symbol, nor is it a tower with a vertical antenna with
circles as others might recognize. It looks pretty much like the
'drawing' above!

___
"Bigguy" <bigguy36@gmail.com> wrote in message
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Posted by none on October 19th, 2007


Didn't know such a group existed. Thanks for the information!
__
"E. F." <pm771.am@gmail.com> wrote in message
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Posted by Steve Midgley on October 19th, 2007


"none" <nospam@bogusaddress.com> wrote in message
news:l42Si.19274$ya1.15057@news02.roc.ny...
There is no external wireless jack on a T41, at least I've never seen one on
the hundred or so I've had. The "jack" you are seeing in the Kensington
security lock attachment point.

Download this for future reference >
ftp://ftp.software.ibm.com/pc/pccbbs...39t6192_01.pdf

SCM


Posted by none on October 19th, 2007


Thanks Steve, looked at the manual and sure enough, the hole I see is
called a security keyhole ... which leaves a question; where does the
cable for the WIFI external go? IS there a port for an external antenna
somewhere?
___
"Steve Midgley" <smidgley@com.net> wrote in message
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Posted by Dave Martindale on October 19th, 2007


"none" <nospam@bogusaddress.com> writes:
Probably not. Many laptops have *two* WiFi antennas connected to the
two jacks on the card. This provides what's called "space diversity".
When you are using a WiFi card and an access point indoors, there are
lots of reflections, and sometimes those reflections add up in such a
way as to almost entirely cancel. When this happens, the computer and
the access point cannot "hear" each other, even if they are otherwise
well within range. The wavelength of the WiFi signal is so short that
when you do get signal cancellation like this, moving the antenna just a
few inches is likely to restore communications.

That's where diversity comes in. By having two antennas a few inches
from each other connected to two receiver frontends, the WiFi card can
continuously compare signal strength from the two antennas during
receive and switch to whichever one provides the better signal at that
moment. If your laptop is stationary, it's likely to pick one antenna
for long periods, but if you're walking around with the laptop it's
likely to be switching antennas very frequently.

Dave

Posted by Steve Midgley on October 19th, 2007


"none" <nospam@bogusaddress.com> wrote in message
news:wm7Si.19444$B25.1147@news01.roc.ny...
There isn't an external antenna normally, unless someone added it. The two
wires from the wireless card go up into the screen. You can see the details
further down in the PDF from IBM.

SCM


Posted by dg on October 20th, 2007


On Oct 19, 2:22 pm, "Steve Midgley" <smidg...@com.net> wrote:
"normally" sounds like a good place to start: If "none" has a lead
trailing over to the (pretty seldom used, many laptop users never-
used) Kensington cable-lock port, why not look at dremelling the lock
out and putting in a mini-coax port for an external antenna?


Posted by Chirishman@gmail.com on November 7th, 2007


On Oct 19, 11:34 am, "none" <nos...@bogusaddress.com> wrote:
That is the locking port. It's for chaining your laptop down. The
symbol you have described is the standard symbol for a computer
locking port which kensington likes to refer to as the Kensington
Security Slot. http://us.kensington.com/html/1356.html



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