internal wifi antenna

I just installed a mini PCI wifi (802.11b) card in my TP600X and also
installed a pair of internal antenna routed just below the keyboard.
The signal received is very weak (one bar). So I disconnected that
antenna pair and hook up a spare and route that one outside if the
laptop. Same weak signal. Looking at the antenna wire, it looked like a
very small coax cable, terminated at one end on a small coax type
connector (center pin and snap ring on the ground side. What bothers me
is the other end. both the center wire and ground is soldered to a thin
metal bracket. So how does this antenna work when resistance wise it is
a short ?
Thanks.

(E-Mail Removed) wrote:
> I just installed a mini PCI wifi (802.11b) card in my TP600X and also
> installed a pair of internal antenna routed just below the keyboard.
> The signal received is very weak (one bar). So I disconnected that
> antenna pair and hook up a spare and route that one outside if the
> laptop. Same weak signal. Looking at the antenna wire, it looked like a
> very small coax cable, terminated at one end on a small coax type
> connector (center pin and snap ring on the ground side. What bothers me
> is the other end. both the center wire and ground is soldered to a thin
> metal bracket. So how does this antenna work when resistance wise it is
> a short ?

It won't work if it's as you described. Would it be too painful to you
to mention the brand/model of the wireless gear?

Hey, it's not worth a pie..........
Go get a card to pop in the slot.
They work better anyway.
I got the top of the range Toshiba & ended up doing that & never regretted
it.



"Rôgêr" <(E-Mail Removed)> wrote in message
news:5sudnZ2dnZ1GsmaHnZ2dnZyFnd6dnZ2dRVn-(E-Mail Removed)...
> (E-Mail Removed) wrote:
>> I just installed a mini PCI wifi (802.11b) card in my TP600X and also
>> installed a pair of internal antenna routed just below the keyboard.
>> The signal received is very weak (one bar). So I disconnected that
>> antenna pair and hook up a spare and route that one outside if the
>> laptop. Same weak signal. Looking at the antenna wire, it looked like a
>> very small coax cable, terminated at one end on a small coax type
>> connector (center pin and snap ring on the ground side. What bothers me
>> is the other end. both the center wire and ground is soldered to a thin
>> metal bracket. So how does this antenna work when resistance wise it is
>> a short ?
>
> It won't work if it's as you described. Would it be too painful to you to
> mention the brand/model of the wireless gear?

It's RF - lots of RF antennae look like a short... at RF frequencies they
are not - back EMF and all that stuff... ;-)

Guy


<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
>I just installed a mini PCI wifi (802.11b) card in my TP600X and also
> installed a pair of internal antenna routed just below the keyboard.
> The signal received is very weak (one bar). So I disconnected that
> antenna pair and hook up a spare and route that one outside if the
> laptop. Same weak signal. Looking at the antenna wire, it looked like a
> very small coax cable, terminated at one end on a small coax type
> connector (center pin and snap ring on the ground side. What bothers me
> is the other end. both the center wire and ground is soldered to a thin
> metal bracket. So how does this antenna work when resistance wise it is
> a short ?
> Thanks.
>

The mini PCI is a Toshiba PA3272U-1MPC, with marking that says Intel
WM3B2100. The driver is from Toshiba website intwlan2100ssox.exe

My AP is a D-Link, and worked fine using my 600E and PCMCIA wifi card.

On 14 Aug 2005 19:52:16 -0700, (E-Mail Removed) wrote:

>I just installed a mini PCI wifi (802.11b) card in my TP600X and also
>installed a pair of internal antenna routed just below the keyboard.

Ummm, most of the laptop internal antennas are routed up to the top or
side of the display section. It won't work very well with the
radiating part of the antenna down low, near the RFI sources, under
the shielded keyboard, etc.

>The signal received is very weak (one bar). So I disconnected that
>antenna pair and hook up a spare and route that one outside if the
>laptop. Same weak signal.

Good thinking. That should have made and antenna work better. Did
waveing the antenna around change the signal level? It's not the
greatest way to tell if it's working, but if the RF is coming from the
antenna, you should see a change.

>Looking at the antenna wire, it looked like a
>very small coax cable, terminated at one end on a small coax type
>connector (center pin and snap ring on the ground side. What bothers me
>is the other end. both the center wire and ground is soldered to a thin
>metal bracket. So how does this antenna work when resistance wise it is
>a short ?

Oh, that's easy. Any antenna that's 1/2 wavelength long is an open
circuit at the resonant frequency. That's about 6mm at 2.4Ghz. To
get 50 ohms, the coax cable is connected to a "tap" that's about
10-20% of the distance from the ground (shield) end of the antenna to
the grounded end point. There are also "slot" antennas, that are a
piece of sheet metal with a 1/2 wave slot and the coax connected
across the slot. Some antennas are "J-poles" which are either 1/2 or
5/8 wavelength long, with a 1/4 wave driven element. Everything is
grounded. There are also ceramic substrate tuned line antennas, which
shrink the wavelength dimensions down to miniature size similar to
what's used inside some cellphones.

Be careful with the u-FL connectors. They are very flimsy, do not
tolerate any abuse, and will break at the slightest provocation. If
your antenna assembly was not designed specifically for your
unspecified MiniPCI card, there may be a connector problem, or you may
have trashed the connector if you forced it. Did it go "click" when
you attached the connectors? That's a good sign that it fits.

Antenna for IBM laptop with some nifty references:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5230419854
Looks like a J-pole antenna.

Installing an internal antenna in an IBM A31 laptop:
http://www.jordanautomations.com/tpa...i-upgrade.html

Ceramic antennas:
http://www.gigaant.com/

Some good stuff on antenna basics and theory:
http://www.gigaant.com/?id=246&lang=1&state=1
(see links in the right window).




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

On 15 Aug 2005 05:01:23 -0700, (E-Mail Removed) wrote:

>The mini PCI is a Toshiba PA3272U-1MPC, with marking that says Intel
>WM3B2100. The driver is from Toshiba website intwlan2100ssox.exe

That an Intel 2100 card:
http://support.intel.com/support/wireless/wlan/pro2100/
It's fairly generic as 802.11b cards go. If the Toshiba drivers
didn't work, try the Intel drivers.

>My AP is a D-Link, and worked fine using my 600E and PCMCIA wifi card.

That means your unspecified model[1] of DLink wireless router works
with your IBM 600E laptop and unspecified[1] wi-fi card and is
probably not the source of the problem.

[1] Kindly disclose the make and manufacturer of *ALL* your hardware
or answers to your questions will tend to be vague and general. It is
also a good idea to mention your exact operating system as driver
issues tend to related to the OS.

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

> Oh, that's easy. Any antenna that's 1/2 wavelength long is an open
> circuit at the resonant frequency. That's about 6mm at 2.4Ghz. To
> get 50 ohms, the coax cable is connected to a "tap" that's about
> 10-20% of the distance from the ground (shield) end of the antenna to
> the grounded end point. There are also "slot" antennas, that are a

etc etc which is why I like digital electronics, there are two states:-

1) it works
2) it doesn't



David.

On Mon, 15 Aug 2005 16:39:10 GMT, David Taylor <(E-Mail Removed)>
wrote:

>> Oh, that's easy. Any antenna that's 1/2 wavelength long is an open
>> circuit at the resonant frequency. That's about 6mm at 2.4Ghz. To
>> get 50 ohms, the coax cable is connected to a "tap" that's about
>> 10-20% of the distance from the ground (shield) end of the antenna to
>> the grounded end point. There are also "slot" antennas, that are a

>etc etc which is why I like digital electronics, there are two states:-
>1) it works
>2) it doesn't

Wrong. Race states, hazards, timing issues, glitches, and state
dependent software bugs makes digital electronics mimic the real world
of analog electronics. Given a sufficiently complex digital system,
the symptoms of digital failure are almost identical to the equivalent
analog contraption.

I like RF because it's all magic. Nothing is consistent, predictable,
or definitive. I can wave my magic wand and make things work one day.
The next day, nothing I do will make it work. The basic problem with
RF (and all electronics) is that you can't see the electrons moving
around. We're basically blind and have to rely on artificial means
(i.e. test equipment) to see what's happening. At best, it's a rather
poor visulization of reality. Computer simulations help but they are
at best science fiction. Anyway, it's fun being a magician. I get to
wear the pointed hat with the stars and crescents, wave a magic wand,
and mutter 4 letter magic phrases over the circuitry. I can also
dispense truly amazing explanations of what was wrong, which takes
care of my science fiction addiction. Frankly, methinks that digital
is boring, where everything is easily predictable, and totally devoid
of entertainment value and magic.


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

> Wrong. Race states, hazards, timing issues, glitches, and state

yeah yeah, I think you missed the subtlety of my humour.

> I like RF because it's all magic. Nothing is consistent, predictable,

A friend of mine built a spectrum analyser, it looked more like meccano
with bits of PCB and ground plane stuff all over the place. Don't know
if it ever worked or how.

David.