Linksys WUSB54GC External Antenna Modification

The Linksys WUSB54GC is avery good performer out of the box, thanks to a Ralink chipset and overall good design. It still has some limitations due to its internal antenna. With the addition of a good external antenna, it rises to excellence.

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This project can greatly increase the throughput and range of the Linksys WUSB54GC. It can also be applied to just about any commonly available wifi adapter or router; one simply cuts out the built in antenna and runs coaxial cable to a high gain replacement. I have seen throughput on a 30 meter path go from 5.5 MB/Sec to a solid 54 MB/Sec - with reduced interference and no need for amplification. Note that longer path lengths (more than 200 meters or through walls and vegetation) may require making this modification to a device higher powered than the WUSB54GC.

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First, look at the circuit board. It boasts an efficient and clean layout. Data passes through a USB port on the left, and the antenna is etched on the right side. This modification is not difficult, but bright lighting and use of a magnifier is suggested due to the small surface mount parts and thin circuit traces on the adapter. The WUSB54GC presents a small work area, so use caution.

Tools Needed:

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1. An X-Acto Knife or razor for cutting traces and trimming coaxial cable.
2. Soldering iron, with the tip sharpend, cleaned, and tinned.
3. One coaxial "pigtail" with conectors apropriate for antenna to be used.
4. Safety wire or epoxy for securing the pigtail to the PC board.
5. Small drill if safety wiring will be used to decure the pigtail.

Modification Procedure:

1. Carefully pry open the adapter and remove it from its enclosure. Plan to work on the area to the right of the shielded circuitry.

2. Cut the printed circuit stripline in the places indicated.
3. If wire will be used to hold down the pigtail, drill four small (1mm dia) holes in a square adjacent to the internal patch antenna.
4. Scrape away the coating over the ground plane in the area near the center cunductor connection point.
5. Carefully prepare one end of the coaxial feedline for soldering to the board (keep it neat and avoid long leads).
6. Connect the center conductor to the "T" shaped tracing; solder the shield to the ground plane (consider drilling a hole to access the excellent groundplane on the back of the circuit board).
7. Wire or glue the pigtail to the circuit board. Make sure it will not flex or rip loose.
8. Carefully cut a gap into the enclosure to accomodate the pigtail, then re-enclose the circuit.
9. Connect the adapter to the antenna; the modification is complete.

Note: This modification is quite similar to the one for the Belkin F5D7050. Look at that page, and become familiar with the general concepts of adding an external antenna to a router or USB wifi adapter.