I had a quick look around the net for a solution and found plenty of people modding there USB Bluetooth dongle to use an external WiFi antenna. I couldn't however find any mods for the IOGear dongle I have, so I read what I could and thought what the hell lets just figure it out........its really not that hard.
So here is my down and dirty Bluetooth antenna mod for the IOGear GBU221. Hope it helps someone and sorry about the pics my phone has no macro function.........Enjoy.
Step 1: The Strip Down
Ok, here we go.
First up you need to crack the case. You will find its just snapped together with plastic clips, I used a small flathead screwdriver but feel free to use whatever implement you like. Be careful not to damage the case or brake any of the plastic clips. If you do don't panic its for that very reason we have duct tape and super glue.
You will be left with a small unassuming circuit board that should look like the pic
On the back on the board at the opposite end of the USB connector you should see a little squiggly track........This is the built in antenna, its not very big now is it?
Step 2: Prepwork
In my box of scrap I had an old wireless router that had this handy little antenna pigtail thingy. On one end was a little connecter (the type that clips on the mini PCI wireless cards for laptops) and on the other end was a nice SMA connector , the type of thing you would find on the back of a Dlink router.
If you don't have anything like the little pigtail thing I found then worst case you could cut the connector of the end of an antenna connect it directly to the USB gizmo.
That's really about all you will need so lets move right along
Step 3: Now the Fun Begins
We need to scratch of the green protective stuff from two places on the underside of the unit. The first place if right where the built in antenna starts if you look at the gizmo the same way it is in the pic the start of the antenna is a slightly longer bit of track close to the bottom edge, if you have good eyes you will also notice that there is a tiny through hole at the start of the antenna. The second scratching needs to be done on the grounding plane; this is the large bit of copper that covers most of the underside of the board. Using that there pointy tip on your soldering iron cover the exposed copper bits with a thin layer of solder, be vary carful not to apply too much heat as you could lift the tracks. If the solder doesnt take the first time dont panic just try scratching a little more.
Just as a side note I used an X-Acto knife to do my scratching.
Next we take our pigtail thingy and cut off the little tiny connector, strip of about an inch of insulation and peel back the braided shielding. Twist all the stands of shielding together so the stick out to one side. Now strip about a quarter inch of insulation from the inner conductor and twist the stands together. Is should start to look something like the pic. Tin both the inner conductor and the shielding. Dont use too much solder when tinning.
Step 4: Almost Done!
Solder the shielding to the grounding plate and cut of any extra wire.
Solder the inner conductor to the start of the built in antenna and cut of any extra wire.
Look at the pic to see how I did it, I am not saying that it is the right way or the best way it is just one way of doing it. I doubled the inner conductor back in a U shape because it was easier to make it fit that way and I thought it may also give it some strain relief.
This is a good time to test it. Plug the dongle in to your computer and check it still works, try an antenna if you get better range then you really are almost done, skip the rest of this stem and move on.
When I tried this there was no change. Dont be disappointed just yet, I found that even with the external antenna it was still using the internal so here is what to do.
With your X-Acto knife or whatever is your weapon of choice cut the track that is the built in antenna just after where you soldered the center conductor. You cant really see this in the pic but its there. Make sure you cut all the way through it. Then test again.
Step 5: Thats All Folks!!
You could go ahead and leave the project the way it is right now and it should work just fine but lets be honest its not the best looking thing to be stuck out of your computer. So we will put it all back together.
We need to modify the plastic shell so that the pigtail can hangout and still allow the shell to close, again the good old X-Acto knife steps in and saves the day, just pick a good spot you want it to hang from and little by little whittle a small groove just big enough for the cable to sit in.
As a side note when I dismantled the gizmo I noticed there was a cool SMT blue LED on the board that lights up real pretty when the device is in use. You cant see this when the case is on so I also drilled a hole in the case to let the mystical blue light out.
Once you have a nice groove for the pigtail you are done, snap the plastic shell back together and enjoy true Bluetooth freedom.
Well almost, I am using a 6dBI directional antenna and it works well, before the mod I could walk about 5 feet from my computer before I started to get static, now I get a good 20 to 30 feet.
Good luck and happy modding