Introduction: Add a Wireless Antenna to Your Eeepc 900a

This instructable shows you how to install a wireless connector to your eeepc, suitable for antennas and such.

So let's say you have an eeepc 900a (or other book of the "net" variety). It's got an okay wireless card, but not much else going for it - all it's good for is surfing the net. You'd like to use (insert wireless resource here) and yet (distance-related limitations, restraining orders, etc). So, you do what any sane man would do - Claim that you are Napoleon Bonaparte, and use an external antenna!

This netbook has no wireless connector built in. So your options are:
a) buy an external usb wireless adapter with a connector on it - circa 50 bucks
b) buy a $5 connector, and mod your netbook at the risk of breaking it.

The correct option of course is b).  ... well.... Unfortunately most USB wireless dongles don't work well under linux (some do but it seems kind of tricky - I've read that sometimes even the same version of the same model has a different chipset, so purchasing the right one can be a pain in the neck). Conversely - although it may take fiddling under some distributions - the eeepc internal wireless happens to work perfectly under the latest version of eeebuntu (which is like... ubuntu.. for eeepc...)

Things you will need:
    - A soldering iron
    - Your wits
    - Solder
    - A reverse SMA MALE connector (thread on the outside, with a pin in the centre)
    - Knowledge of the principles of static electricity  (Antistatic wrist strap, if one thou hast)
    - Your wits
    - A screwdriver (one flat, and one tiny philips head, for tiny screws)
    - Electric drill and drillbits
    - A retractable blade thingy. For sharpening your wits. And, just in case.
    - An almost legendary disregard for the sacred bond between warrantee and warranteur.

Step 1: Disassemble Your Netbook

TigerOnEeePc already has a great youtube tutorial on how to disassemble the main body of your netbook and removing the motherboard. PLEASE WATCH all parts of the tutorial or you'll probably break something - there are little release tabs in the keyboard and other things you need to look out for.  (I could have included my own instructions but... he did such a great job that there's no point.)

the difference here, DON'T remove the wireless card or memory cards from the motherboard, just unplug the antennas (seen in the second photo). everything else, keyboard, motherboard, you can remove and put somewhere safe. I suggest you place the motherboard underneath the cat while you rub it frantically with a balloon - uh - on second thought, leave it on your desk.

(disclaimer: Any stickers that you remove or break might end up voiding whatever it is the sticker says it will void if you remove or break it. If you don't know how to handle sensitive components, etc! Vis a vis! Consequently! Ergo! etcetera!)

Next I will explain disassembling the screen, which is necessary to get at the antenna.

Step 2: Take That Screen Apart

Remove the little plastic/rubber dots that are on your LCD screen. Both the rubber ones and the plastic ones at the bottom. Don't feel guilty about this - they'd do the same to you if they had the chance.

When you remove all the rubber dots, a small amount of poison gas will be released from the holes. Hold your breath for nine seconds.

Unscrew the screws.

There are plastic tabs preventing you from pulling the plastic border off. Using the flat screwdriver, carefully work your way around the edge. Don't stab the screwdriver into the lcd panel or anything.

if you undo the screws holding the LCD panel down, you can remove the whole thing (not the black screws on the sides of the LCD panel, but the screws on each corner). . I recommend this, because then you have an empty shell and you can pretty much hurl it across the room without breaking it. (warning, do not hurl across room).  the camera, microphone, a couple of wires and cpu fan can stay there.

Step 3: Drill a Hole, Insert Connector

take to the empty plastic shell with an electric drill - i recommend  the gap under the motherboard, between the ethernet port and single usb port. There is space here because other models included a modem or something

use a drill bit. Also, use one of the correct size (so the connector fits in). place the hole as low as you can get it, and it should fit.

now, once you insert your connector, you may realise that it is a PCB right-angled affair, and entirely the wrong shape. If this happens, have-bought a different style of connector. Alternatively, cut off the bottom part by carefully sawing around in a circle. Don't pull the front off or it'll just break off the core. Instead, maybe grip the core with pliers and push it through instead of pulling.

However - I broke it (see last photo) and it was fine, I just soldered whatever was sticking out.. The important thing is that it fits, and you can solder on the antenna cable. Do what you gotta do - if you think your connector will fit inside without touching other components, just insert it as-is

a word regarding these connectors : if you buy one and there is a pin with a hole in it floating around in the packet, you have the wrong connector. this hole in the middle is actually a female connector, not a male. Make sure it is a REVERSE SMA  MALE.  Also see if you can get a long one with a nut that screws onto it, because this will make it much easier for you to keep it fixed onto the case - if i had to do this again, i'd try finding something like this so i wouldn't have to stuff around as much with glue or whatever

Step 4: De-solder Antenna Cable, Reroute It to the Connector

The network card has two antennas connected. I decided to just use the lowest number connector and, to be honest i am not sure how important this is - they are identical shaped antennas and so, there is no way to discern between them. I read on a forum that you should use antenna 1 for an external antenna because then it will (something good). I cannot confirm this. However, after finishing this project i discovered that the wireless refuses to function at all unless an antenna is plugged in (probably because the circuit is then open). I'm not sure if using the second plug would solve this? try it if you want. they are actually labelled something like "J2" and "J3" - maybe J1 is earth.

there is a black wire and a white wire, they are each soldered to separate antennas (i.e, some stupid squiggle of sheet metal) at the top of the screen. Use the white wire because you'll get more slack - when you put it back together you just plug the white cable into the wifi card input you want to use.

I'm pretty sure you shouldn't connect both lines together on one antenna. I am not an expert but my thinking is that both antennas are used simultaneously to increase bandwidth - so if they were on the one antenna the signals would interfere with each other and mess everything up

Anyway... The cable consists of a core wire receiving/sending from the antenna, and an outer mesh soldered to earth. solder the core of the wire to the core of the connector - and the outer mesh to the body of the connector.  Make sure they aren't touching together or anything.

I did the above before attaching the connector permanently to the case. I glued it in and stole a little washer from my wireless router, just to solder onto the outside and fix it in place (as you can see there is not enough room for the nut to go on)- this was a bit uncivilised, see if you can do a better job of it by getting a longer connector, and a nut to hold it in place

Step 5: Finishing Up

now carefully put things back together, basically doing the reverse of what you did before and making sure wires from the screen go through the hinges properly without getting jammed.

the only problem to watch out for is when you put the motherboard back - there are plastic tabs that you had to push to get it out, and when you put it back you need to push these tabs again - if you forget they are there and try pushing things in, it might just snap them. which is kind of what i did.

Plugging the keyboard back in is fiddly so try some needlenose pliers wrapped in tape so as not to damage the ribbon cable

once your netbook is back together and everything is screwed in right, plug in the antenna and see if it all works. since you took out the battery in step 1 you'll need to set up the bios again. Remember you need to enable the webcam if you use linux (well, if you need to use it).

If you didn't plug an antenna in, you'll probably notice that the wireless interface does not to want to connect to anything, and may not exist. Don't panic - After I plugged an antenna to the connector and turned it on, after that the wireless worked. Like I said, it will fail when nothing is connected, because it's an open circuit. I doubt this will cause any problems but, if this worries you just make sure there is always a small wireless antenna plugged in before you turn on the netbook. (And if you're that worried about damaging it, you probably shouldn't be doing stuff like this anyway).

(Update: I solved this by soldering a 50ohm resistor across a female connector - this can be used to terminate the connection when not using an external antenna)

I found that with a directional wireless antenna i could pick up more access points, presumably from a greater distance. I haven't tried an omnidirectional one yet, but i'm fairly sure it'll increase my range. To be honest I spend most of my time less than 5 meters from my own wireless router, so this was a fairly pointless endeavor. But as an electronic technician, I feel it's my duty to add "useless" features to any hardware i happen to find, especially when it's low hanging fruit such as this.

Comments

author
Hueristic (author)2015-07-21

Nice, I like your attitude. PM'd

author
MRedu (author)2011-10-18

Whoa! that's one hefty looking antenna!

author
markgobbin (author)MRedu2011-10-19

yes... although the computer itself is less than a handspan tall. you should have seen the yagi

you'll be glad to know that i since broke the connector by dropping my netbook - twice - and in the end reversed everything i did, wadding some putty into the resulting hole. its what three years old, not too bad i'm still using it as we speak

And that concludes the advanture of my netbook, huzzah!

author
markgobbin (author)2010-09-16

I didn't realise i had to post this again. Curses!

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