Who makes retractable antenna for laptop card?

What manufacturers make a laptop PC-Card that has a retractable antenna,
which otherwise can be dangerous if you move the laptop with a protruding
antenna and forget to pop out the card. A friend once cracked his laptop's
motherboard after hitting a door with the antenna portion of his wireless
card.

If they exist:

Make?

Model?

Pat wrote:

> What manufacturers make a laptop PC-Card that has a retractable antenna,
> which otherwise can be dangerous if you move the laptop with a protruding
> antenna and forget to pop out the card. A friend once cracked his laptop's
> motherboard after hitting a door with the antenna portion of his wireless
> card.
>
> If they exist:
>
> Make?
>
> Model?
>
>
>
3Com do some with the "X-Jack" antenna. I have the 11g version, and I'm
very pleased with it. I didn't want to have to remove the card when I
put then laptop in it's bag.

They're a bit pricey compared to linksys etc though.

http://www.3com.com/prod/en_UK_EMEA/...&sku=3CRPAG175

On Sun, 04 Jul 2004 14:52:44 GMT, "Pat" <(E-Mail Removed)> wrote:

>What manufacturers make a laptop PC-Card that has a retractable antenna,
>which otherwise can be dangerous if you move the laptop with a protruding
>antenna and forget to pop out the card. A friend once cracked his laptop's
>motherboard after hitting a door with the antenna portion of his wireless
>card.

Well, they're available for Bluetooth:
http://www.psism.com/pcabt1.htm
but I couldn't find a similar 802.11 wireless card construction.

Many of the older Proxim PCMCIA (Symphony, Rangelan, HomeRF) wireless
devices had removeable antennas. For example:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3490602129
However, those antennas tended to disappear, break off, or develop
intermittant connections. Not recommended.


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

"Pat" <(E-Mail Removed)> wrote in message
news:0RUFc.15876$(E-Mail Removed)...
> What manufacturers make a laptop PC-Card that has a retractable antenna,
> which otherwise can be dangerous if you move the laptop with a protruding
> antenna and forget to pop out the card. A friend once cracked his laptop's
> motherboard after hitting a door with the antenna portion of his wireless
> card.
>
> If they exist:
>
> Make?
>
> Model?
>
>
>


Pat,

There are two 3Com products that use the patented X-Jack antenna that
retracts into the PC Card when not in use. The first is the a/b/g PC Card
($135 List)

http://www.3com.com/products/en_US/d...&sku=3CRPAG175

The second is the .11g card ($76 list)

http://www.3com.com/products/en_US/d...sku=3CRSHPW196

Grant

"Grant Jones" <(E-Mail Removed)> wrote in message
news:KdAGc.2$(E-Mail Removed)...
<snip>
> There are two 3Com products that use the patented X-Jack antenna that
> retracts into the PC Card when not in use. The first is the a/b/g PC Card
> ($135 List)
>
>
http://www.3com.com/products/en_US/d...&sku=3CRPAG175
>
> The second is the .11g card ($76 list)
>
>
http://www.3com.com/products/en_US/d...sku=3CRSHPW196
>
> Grant

I had the 3Com 11a/b/g card (3CRPAG175) and had to return it because it was
causing lockups in my Dell Inspiron 8000. Strangely the lockups only
occurred at 11g speeds and not 11b (Win XP Pro) but was fine at any speed
under Win Me.

I also have the 3Com 11b card and have kept that as it works fine. Both have
the retractable antenna. However, I would have to say that the RF
performance is compromised by the retractable antenna design and I get much
better results with my Netgear WG511 that replaced the 3CRPAG175.

"Tiny Tim" <_(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> I also have the 3Com 11b card and have kept that as it works fine. Both
have
> the retractable antenna. However, I would have to say that the RF
> performance is compromised by the retractable antenna design and I get
much
> better results with my Netgear WG511 that replaced the 3CRPAG175.
>
>

Retractable seems like a great idea. So far, I like the Netgear WG511T but
its drawback is a big fat antenna that protrudes.

On Wed, 07 Jul 2004 23:47:16 GMT, "Pat" <(E-Mail Removed)> wrote:

>Retractable seems like a great idea. So far, I like the Netgear WG511T but
>its drawback is a big fat antenna that protrudes.

For a PCMCIA card, you want a big fat antenna that protrudes. That's
because the thin, low profile, slightly protuding type of antenna are
invariably half wave dipole traces on G10 circuit board material. The
dipole is "folded" which reduces its gain. G10 is also very lossy at
2.4Ghz. Basically, the circuit board antennas are cheap and suck.

For an example of one of these antennas, see photo at:
http://jeffl.ihwy.com/linksys/wpc11/ls-pcmcia-0.jpg (120K)
The two hook shaped traces are the two elements of the dipole.

The big fat protruding antennas are usually ceramic substrate dipoles
or patch antennas. Ceramic has a high dielectric constant and shrinks
the effective length of the antenna so it will fit better in the
package. It also elevates the antenna above the lossy G10 circuit
board. The catch is that this elevation makes the protruding part of
the card rather large and lumpish. Tough. That's what it takes to
make a decent antenna system.

Now, if I could only get people to not use the antenna as a handle.

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

On Thu, 08 Jul 2004 00:37:44 -0700, Jeff Liebermann
<(E-Mail Removed)> wrote:


>For a PCMCIA card, you want a big fat antenna that protrudes. That's
>because the thin, low profile, slightly protuding type of antenna are
>invariably half wave dipole traces on G10 circuit board material. The
>dipole is "folded" which reduces its gain. G10 is also very lossy at
>2.4Ghz. Basically, the circuit board antennas are cheap and suck.
>
>For an example of one of these antennas, see photo at:
> http://jeffl.ihwy.com/linksys/wpc11/ls-pcmcia-0.jpg (120K)
>The two hook shaped traces are the two elements of the dipole.

Is it possible to attach an external antenna to the WPC11 without
destroying it?

On Sun, 11 Jul 2004 21:28:06 -0700, Hamish McStill <(E-Mail Removed)>
wrote:

>On Thu, 08 Jul 2004 00:37:44 -0700, Jeff Liebermann
><(E-Mail Removed)> wrote:
>>For a PCMCIA card, you want a big fat antenna that protrudes. That's
>>because the thin, low profile, slightly protuding type of antenna are
>>invariably half wave dipole traces on G10 circuit board material. The
>>dipole is "folded" which reduces its gain. G10 is also very lossy at
>>2.4Ghz. Basically, the circuit board antennas are cheap and suck.
>>
>>For an example of one of these antennas, see photo at:
>> http://jeffl.ihwy.com/linksys/wpc11/ls-pcmcia-0.jpg (120K)
>>The two hook shaped traces are the two elements of the dipole.

>Is it possible to attach an external antenna to the WPC11 without
>destroying it?

With my web site of "LearnByDestroying", you ask such a question?
Enlightenment comes only after much suffering and the sacrifice of
hardware.

However, I'm working on the method of doing this without rampant
destruction right now. It's the same technique that I use to couple
an external antenna to a GPS (1575Mhz) that has no external antenna
connector. Basically, it's a full wave loop antenna, wrapped around
the PCMCIA card antenna, coupled to a coax cable, when ends up
connected to an external antenna.

It works well with a GPS because the external antenna has +25dB of
gain making the antenna amplifier the prime determination of
sensitivity. A little loss at the coupling isn't going to make much
difference in a GPS. Unfortunately, I don't have this advantage with
a 2.4GHz wireless card. I have to couple efficiently. Resonant
coupling is tricky because the resultant tuning would be rather
mechanically critical.

So far, the best I've done is turn the meandering line antenna (MLA)
or PIFA (patched inverse "F" antenna) into part of a big coupling
loop. It's a flat 3mm wide, 12.5cm long, flat copper strip wrapped
around the PCMCIA card. It's amazing and pure luck that the length of
a full wave loop fits perfectly around a PCMCIA card. I've been able
to couple +4dBm out to my spectrum analyzer, which is about -8dB
coupling loss (ignoring about -2dB loss in the coax cable and
connectors). Not very good, but better than no antenna at all.

Most of the loss is in the impedance mismatch between the very high
loop impedance and the 50ohm coax impedance. I'm playing with various
loop configurations and matching schemes right now. If I can get -3dB
coupling loss, I'll consider it done. Incidentally, I decided that I
couldn't use a patch antenna for coupling because over half of the RF
from the card will radiate away from the patch an not be coupled to
the coax. The loop goes all the way around the card and should grab
all the RF.

In theory, the best will be a 12.5cm circumference loop, in the form
of a solid flat wire ring, with one point designated as the ground
point (where the coax shield is attached), and some point around the
circumference as the 50ohm tap, with a tuning capacitor in series from
the tap to the coax center conductor (to tune out the inductance of
the exposed center conductor). This is a gamma match which is
disgustingly narrow band and seriously critical in tuning. I've had
the loss down to -2dB but found the construction to be so critical
that simply moving anything will detune the gamma match. Obviously,
this isn't gonna work at a coffee shop.

I've given up for the day. Photos, when I have something worth
photographing. If you wanna tinker, just take a 12.5cm long wire and
solder the ends to a piece of 50ohm coax. Make sure that the 12.5cm
length includes the exposed part of the coax cable. Bend the loop
around the antenna part of the PCMCIA card. Position the coax at the
edge of the card, not the top or bottom to prevent coupling directly
to the coax. It won't be fabulous coupling, but it will be better
than no external antenna.


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

In article <(E-Mail Removed)>,
(E-Mail Removed) says...
> For a PCMCIA card, you want a big fat antenna that protrudes. That's
> because the thin, low profile, slightly protuding type of antenna are
> invariably half wave dipole traces on G10 circuit board material. The
> dipole is "folded" which reduces its gain. G10 is also very lossy at
> 2.4Ghz. Basically, the circuit board antennas are cheap and suck.
>
> For an example of one of these antennas, see photo at:
> http://jeffl.ihwy.com/linksys/wpc11/ls-pcmcia-0.jpg (120K)
> The two hook shaped traces are the two elements of the dipole.
>
Do not take this as a flame but I believe that these are NOT two
elements of one dipole but instead are 2 individual diversity antennas
that are selected by the RF switch (black IC right below L10 or left of
C96).
Each probably acts as an individual 1/4 or 1/2 wave antenna with all the
ground plane acting as a counterpoise.