Antenna Modification for Buffalo Air Station g54

Model no. WLI-U2-KG54-AI

 

 

(Fig 1.0 Completed project. G54 fitted with a RT-SMA socket pigtail)

 

 

PCB layout

The Air Station g54 is a USB2 based Wi-Fi adaptor based on the Ralink rt2570 chipset.

 

 

(Fig 1.1 The g54 follows the Ralink reference design closely)

 

Choice of pigtail adaptor

I decided to attach a pigtail terminated with a Reverse SMA socket as this offers the best connectivity to my external antenna collection.

 

 

(Fig 1.2 RT-SMA socket and are bares wires)

 

 

How to perform the modification

Step 1. Locate appropriate point for soldering

 

Upon examination of the PCB I noticed that Buffalo had omitted to include an MS-156 connector.  We will use this area to solder our pigtail to the board.

 

 

(Fig 1.3 Where to solder the pigtail)

 

 

Step 2. Tin the pigtail wires using Alloy 60/40 Solder

 

 

(Fig 1.4 Tinned pigtail wires)

 

 

Step 3. Solder the pigtail to the PCB

 

Carefully solder the pre-tinned wires to the PCB using a 15w (or less) soldering iron. Be careful and apply as little heat as possible to avoid damaging the PCB and nearby components.

 

(Fig 1.5 Soldered to PCB)

 

Step 4. Test the pigtail

 

Attach an external antenna to your pigtail.  Be careful and do not disturb your freshly soldered connections as they will be very weak.

 

Use Kismet or NetStumbler to check connectivity with and without an external antenna.  As you can see I picked up several new access points in my local area the instant I connected my 5dB omni antenna.

 

 

(Fig 1.6 Kismet using cards internal antenna)

 

 

 

 

(Fig 1.7 Kismet using 5dB omni antenna)

 

Step 5. Captivate the pigtail inside the case

 

Using a hot glue gun, stick the pigtail cable to the PCB.  Make sure you leave lots of slack and don’t glue in areas that will inhibit the case from connecting back together.  I also placed a little hot glue behind the solder connections to isolate them from nearby components.

 

 

(Fig 1.8 Hot-glue to captivate wire)

 

 

(Fig 1.9 Note: The components under the cable are isolated with glue)

 

 

(Fig 1.10 The wire is given lots of slack and glued at both ends)

 

 

(Fig 1.11 Hot-glue us fun!)

 

 

Step 6. Put it back together

 

Make a small hole in the side of the case for the wire to exit.  I used a small pair of wire snips to cut the plastic but in hindsight it may have been neater to use the soldering iron to melt the plastic.

 

Snap the case back together and enjoy the fruits of your labour.

 

 

(Fig 1.12 The completed project)

 

Disclaimer

The 54g and most of the other Ralink 2570 based devices are pretty easy to mod if you have the right tools and skills.  If you’ve never soldered anything before then your brand new wireless adaptor is not the place to start!  If your house burns down and girlfriend ditches you don’t come crying to me.

 

If you have comments on this tutorial or you get stuck please feel free to email me: scandalous at softhome dot net and I’ll try to help. If you would like to buy a ready made and tested device drop me a line.

 

Useful links

 

http://rt2x00.serialmonkey.com/phpBB2/index.php - A terrific forum for using these devices in Linux

 

http://www.netstumbler.com – If you want to stumble in Windows go here

 

http://www.kismetwireless.net – If you want to stumble (and do other things) in Linux go here

 

http://www.cr0.net:8040/code/network/aircrack - If you want to pen-test wireless networks, this is the de-facto tool.