totally amateur question: How to attach an antenna to my laptop?

Hi,

I have a thinkpad T40 running OpenBSD and live in a small, nice city
close to Barcelona whose city hall offers free wifi Internet to
everybody.

Unfortunately they do not have a good coverage and where my building
is, I don't get any signal. The card is identified by OpenBSD as ath0,
which means it's Atheros.

Now, I am thinking of building an external wifi antenna but I don't
have the slightest idea of how to do it. I don't have the time
(unfortunately! it looks fun!) of building the antenna by myself, like
here

'Antenna on the Cheap (er, Chip)'
(http://www.oreillynet.com/cs/weblog/view/wlg/448)

so that I'd buy one. The problem is... which one? I have seen a lot of
them in ebay but I'm not sure they are for the laptop and not just for
the router, to enhance its signal.

This guy seems to have managed to do exactly what I would like

'PORTATIL IBM CON ANTENA WIFI 9 DBI EXTERNA Y 2 BATERIA en venta en
eBay.es (finaliza el 27-ene-08 14:55:38 H.Esp)'
(http://cgi.ebay.es/ws/eBayISAPI.dll?...m=320208914420)

So, my question is

1) which kind of antenna do I need? I think I will need to increase the
coverage radius to up to 1-2 km

2) how do I attach the antenna to the thinkpad?

3) will it be compatible with the card?

4) will the OS automatically "see" a broader range? I mean, is it
something mechanical or will I have to play around with the driver?

thanks in advance!

Pau


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pau wrote:

> I have a thinkpad T40 running OpenBSD and live in a small, nice city
> close to Barcelona whose city hall offers free wifi Internet to
> everybody.
>
> Unfortunately they do not have a good coverage and where my building
> is, I don't get any signal. The card is identified by OpenBSD as ath0,
> which means it's Atheros.
>
> Now, I am thinking of building an external wifi antenna but I don't
> have the slightest idea of how to do it.

<snip>

> 2) how do I attach the antenna to the thinkpad?

A quick check of the web shows that your laptop has a mini-pci internal
wireless adapter with connections to diversity antennas in the case
(probably the lid). You will need to do some significant modifications
to provide connections to external antennas (possibly two needed
depending on how the diversity system is configured) -- not for
the inexperienced or those lacking time and patience.

A better bet would be to use another WiFi adapter: either USB or PCMCIA
with an external antenna connector already provided.

Regards,

Michael

On Wed, 23 Jan 2008 15:33:05 -0500, pau
<(E-Mail Removed)> wrote:

>I have a thinkpad T40 running OpenBSD and live in a small, nice city
>close to Barcelona whose city hall offers free wifi Internet to
>everybody.
>
>Unfortunately they do not have a good coverage and where my building
>is, I don't get any signal. The card is identified by OpenBSD as ath0,
>which means it's Atheros.
(...)

See:
<http://repair4laptop.org/wireless_lan_antennae.html>
which list a variety of methods of adding external antennas.
Unfortunately, there's nothing specific for the T40, although some of
the other installations may give you some ideas.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

It seems like a lot of trouble to connect an antenna directly to your
built in thinkpad radio.

There is an easier solution that will leave your laptop in good
condition for resale and give you a device that works with all
computers.

Buy a USB wireless adapter with either a very good antenna, or, better
yet, an external antenna connector plus antenna.

Something like this: http://www.wlanparts.com/product/EUB-362-EXT

Or this one with a fixed, but good dish antenna:
http://www.gohawking.com/store/produ...roducts_id=140

If the antenna for the first product is not strong enough, you can put
a home made reflector on it:
http://users.picknowl.com.au/~gloaming_agnet/ant2.html

Or for best reception, put a directional antenna like this (may need
an adapter to connect):
http://www.wlanparts.com/product/24E...BI_24EB14.html

Most important will be to find the best place for the antenna.
Something with a good view to the city hall and no walls or trees if
possible. You may have to run it outside your building with a USB
extension.

Steve