DIY Box Reflector - sick gainz!

The gear needed for wardriving

1 post • Page 1 of 1

Postby SkywardLark » Tue Sep 14, 2021 3:50 am

This is not my original idea, it's my practical implementation of the Ez-10 corner reflector. It makes omnis directional like a dish would but it's less picky about conditions. You can make this thing in 15 minutes, it costs nothing and it folds for storage. I got a 10 dBm signal difference to a faraway access point.

Materials:
Your favorite USB wifi adapter + USB extension cable
I recommend a Terow ROW02CD (MediaTek MT7612U) with CD driver https://smile.amazon.com/dp/B086L6TR6G/
Boxcutter
Rectangular box, as big as you can feasibly make and use
recommended: used USPS 1095 sized box
approx: 15" (L) x 12" (W) x 3-1/8"(H)
Shipping Tape
Aluminum Foil

Warning: Exceeding EIRP limits is generally illegal

1. Make two cuts into your box to chop off one of the short sides. Your box should now open like a trifold.
2. Cut off the folding flaps from the top of the box. Save them.
3. You will make slots and thread a cardboard flap through for structural support. Cut slots near the top of the box.
4. As neatly as you can, grab your reel of aluminum foil. Tape aluminum foil on the two inside walls of the box.
5. Take off your antennas if they are removable. Make a hole and jam your adapter through. Hook the antennas back up. Hook the adapter to the USB extension cable.
6. Thread flap through slots
7. If you have a two antenna adapter, deploy them in a V shape. You may hang the top antenna off the flap for support.

Adjustments:
-Connect to the AP and run "watch -n0 iwconfig" in Linux. Steer your antenna towards the AP. Stop steering when bit rate, link quality and signal level look good.
-Indoors = Signals will bounce. If you do not have direct line of sight sometimes pointing slightly away from the AP works better.
-Beamforming may affect results
-Making the walls bigger will improve gain with diminishing returns
-My reflector is probably incomplete since I don't have any foil in the middle. I don't know if putting it that close to the adapter causes interference, will test later.


References:
http://www.freeantennas.com/projects/Ez-10/
https://en.wikipedia.org/wiki/Corner_reflector_antenna

Edit: Added picture of a v2 I made. I did not chop off the flaps so the box is taller and I added foil to the middle section.

"The spacing of the rods D should not be more than 0.06 (6%) of the wavelength." -Wikipedia

I'm not sure if that instruction is properly cited but it would suggest you want continuous foil if possible. The wavelength of 2.4 GHz is about 12 cm and 5 GHz is about 6 cm. 6% of those lengths is basically nothing.

v2 achieved best performance with the antennas deployed parallel, while v1 seemed to like the V pattern. In terms of performance both reflectors work, I didn't compare them very hard. Someone more knowledgeable should chime in.
Attachments
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