WR703N – External Antenna

I wanted to extend the range of the WR703N to allow it to pickup more access points. My mini 4GB USB drives have also arrived in the mail, so this makes it the perfect time to start the mod.

Here we have the devices used to complete the mod: 4 port unpowered USB hub, DLink external antenna, female SMA pigtail, 4GB Sandisk USB flash drive, and a WR703N running OpenWRT.

Materials Used

Materials Used

Opened the case to see where the internal cable and mount can run. Decided off center of the 2 edges in the picture below.

Checking where to drill

Checking where to drill

To start off open the WR703N case and drill a hole for the pigtail. Make sure the hole is low enough so that it doesn’t interfere with the lid. You might be able to see I also used a pocket knife to shave the 2 vertical plastic lines off around it.

Drill hole in casing

Drill hole in casing

Prepare the main board by de-soldering the USB port. You also need to de-solder J1 (reference): J1 is a 0 ohm resistor shunt that provides a convenient way to disconnect the printed antenna on the other side of the PCB from the chip. Its pad closest to the U1 chip and the large GND pad on its right can then be used to solder an external antenna.

De-solder USB port

De-solder USB port

Disassemble the USB hub and solder it as I have shown here. I removed 2 of the USB cables from the hub, 1 goes to a USB port which holds the mini flash drive. I then wrapped flash drive holder in plastic (sticky tape) to prevent it from shorting, and used another piece to hold the USB hub in place.

Assembled internals

Assembled internals

Route the pictail cable under the USB hub and solder the inside cable to the contact pad of J1 that’s on the right of the picture above or the lowest one in the picture above this one. Then solder the ground mesh to the large ground point above that.

Place the lid back on and screw on the antenna.

Final with backup battery

Final with backup battery

I purchased another phone backup battery to use, it’s 2000/mah which is bigger than the previous one I used.

UPDATE 7-9-12

Sandisk USB flash drive turned out to be a dud… aparently there are many problems with Sandisk USB thumb drive getting locked into read only mode… Great feature, but not what I’m looking for…

4 thoughts on “WR703N – External Antenna

  1. Hi,
    how did you get the thumbdrive to work? I also have the WR703N with openWRT but I couldnt install the FAT drivers because the WR703N only has 4MB of flash. How did you get it to work? I would like to install an FTP server.
    Thank!

    • Firstly I found that you need good power and generally larger physical sized thumb drives worked better, you also need some packages. Google “WR703N pivot root”. Your better off using ext3/4 file system.
      Sorry for the delay.

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