Internal Wifi External Antenna Mod. Pics

[nobb]

Hi.
I have an Inspiron 6400 and I want to mod it for better wifi reception. I thought I could easily solder on a longer wire to my wifi card to boost reception. I did something similar with my garage door opener and it worked. However, for my wifi card, it was a bit more complex. I took it apart, but cannot determine the location of the antenna. Here are the pictures:

Image1

Image2


The two wires (black and white) run into the LCD screen, but I am guessing they are for power? But it is strange that a power wire would run from the LCD screen, rather than be directly attached to the motherboard, which is much closer. For these internal wifi cards, isnt the antenna usually buried somewhere in the LCD?

Maybe someone can help me out and tell me if it is possible to add an external antenna to this card. If so, where would I attach it?

 

[PottedMeat]

Those triangles point to the dual antenna cables ( the black and white wires ).

If you have a cable you can run it to an external antenna, those are standard connectors Hirose U.FL or something - can't remember right now.

Something like this:

http://rocky.digikey.com/WebLib/Hirose/Web%20Photos/U.FL-R-SMT(01).jpg

 

[Nathelion]

Umm OK to begin with, the wires are NOT the antenna for these things. The wires connect the antenna to the wifi card. The actual antenna is a thin metal rectangle that is attached to the end of the wire. So if you add a longer wire, all you're doing is adding more resistance and dampening the signal. The screen is the best place to place the antenna, and i think most oems do so - however, i wouldn't bet money on it. It would certainly be easier to assemble the system if the antennae was placed in the body.

 

[PottedMeat]

Basically instead of using the integrated antennas Dell put into the screen, you could run a extension cable from the wifi card to the outside of the laptop case to a new antenna you provide. It would be interesting if you could maybe run a extension ( 50 ohm probably ) coax cable from the wifi card to a SMA connector or something on the outside of the case - from there you could experiment with any antenna you like. It may be hard to find a cable so I'd just dig out the existing cables and reroute them outside. However it's pretty cramped already in a laptop case and it may be impossible to find a spot to drill holes for a SMA bulkhead connector.

I'd probably enjoy trying it but if you dont want to do all that then just buy a PCMCIA WiFi card and you can mod that instead without fcuking with the laptop.

 

[nobb]

PottedMeat: Yes, that is what I want to do, but I dont know where to connect the external antenna. I though an antenna was a single conducting lead (like, in the garage door opener I modded). In your proposal to use coax cable, where do I connect the center lead to the wifi card? Where do I connect the outer sheath of the cable?

I think I need a definitive answer for whether those two wires (black and white, with the triangles) are actually antenna wires before I try anything. There seems to be conflicting views on whether those leads are antennae or not.

 

[PottedMeat]

Generally it works like this:

Example Picture:

http://www.icop.com.tw/images/wirelss_lancard.jpg

In the picture the white labels MAIN(B) and AUX(A) are antenna connections.

WiFi Card Female Connector(s) <-> Male Connector on Coaxial Cable -> Coaxial Cable <-> Connector or direct solder connection -> ANTENNA STARTS HERE

Basically the coax cable is needed to bring the signal to a place where you can attach the antenna. In this case the card has dual antenna outputs and has 2 cables that lead to the back of the LCD where the antennas are mounted. This is the best unobtrusive place to get the best signal on a laptop. You really simply cannot remove the cables and solder on a 1/4 wave or whatever wire on the card, there's no space.

I would try to find a cable with the correct connector or reuse the existing coax cables, however you can solder on a coax directly. The sheath is ground and the center conductor should be clearly marked. It's a very tiny soldering job and you may end up delaminating the traces making it nearly impossible to fix.

 

[nobb]

Thanks for the detailed info. Just to confirm. So in my case, assuming the use of a coax, I can solder the center conductor to the white wire and the sheath to the black? Does it matter if I do it vice versa?

 

[PottedMeat]

Originally posted by: nobb
Thanks for the detailed info. Just to confirm. So in my case, assuming the use of a coax, I can solder the center conductor to the white wire and the sheath to the black? Does it matter if I do it vice versa?

There are 2 antennas with 2 coax cables - one white and one black in your picture. Each coax has an outer grounded sheath and a center conductor.

http://rocky.digikey.com/WebLib/Hirose/Web%20Photos/U.FL-R-SMT(01).jpg

In that picture the center terminal is for the center conductor in the coax and the ring is for the sheath. The wifi card should have a similar terminal for each cable.

I would avoid doing this unless I knew I could undo it or not damage the board.

 

[mindless1]

I would advise against soldering to the card. IMO, the three best options are either to take out the existing antenna and reuse it, or buy another antenna cable with the connectors on it (ebay or web) like this,
http://cgi.ebay.com/One-WiFi-mini-PCI-C...FL_W0QQitemZ180104380820QQcmdZViewItem

Then you remove the antenna element from the other end of the cable and attach the type of antenna you want. Antenna type is a whole other topic in itself and made more difficult when it means it has to be mobile for the notebook. If it were just some rubber ducky attached to a R-SMA you installed on the notebook case it might not even work much better than the existing antenna, though at least if you bought a 2nd antenna instead of cannibalizing the present you could at least switch back and forth between the two for testing in any environment.

OR #3, instead of soldering something yourself you use a ready-made R-SMA connecting option as found on ebay et al, it might be called a "U.FL to male RP-SMA" (or substitute "R-SMA" or "RSMA" for "RP-SMA" when doing keyword searches

http://cgi.ebay.com/BEST-U-FL-to-male-R...QQihZ008QQcategoryZ61816QQcmdZViewItem

Also browse around above linked ebay seller's site and elsewhere for other ideas and other already purpose-built OEM laptop antenna-cable combos but I think the last link above was probably what you're wanting so long as you can find a good place on the laptop case to mount it.