Introduction: A Quick, Dirty, and Effective Reflector for the Lab Network

By thomasasmuth.com

This week I moved the Wireless Router to the front of our property. The router of course has a rubber ducky antenna. The nature of a monopole antenna is to radiate the signal in all directions equally forming a doughnut like cloud of radiation. Because the signal of the box is omnidirectional and it is literally located on the front edge of our property this means I am radiating signal to the neighbors across the street.

The solution is to whip up a parabolic reflector to:
  1. keep the signal toward my property
  2. extend the signal to the back reaches so I can listen to internet radio in my fabrication shop
  3. do it all in 10 minutes... ok 15min. so I can get a coke and the materials together.

Step 1: Materials


You probably have these materials around the house:
  1. aluminum foil
  2. sheet of card stock (8.5 x 11 or so) I am not being very mathematically precise here, it is a quick dirty job
  3. glue stick or some adhesive substance to adhere our foil to the shape card stock.
  4. Skewers—to help you shape the parabolic form. I have seen people use wire and even string before; anything to help it pull into shape.
  5. and lastly I used poster tack—that blue goo but it isn't pictured

Step 2: Foil the Cardstock

  1. Put glue on the entire face of the card. The edges are tough to get you may want to put a piece of paper down so as not to smear glue on the table.
  2. Tear off a piece of foil larger than the card
  3. Lay down the foil and smooth from the inside to out. I used the glue stick container because it was nice and smooth. You can use an small piece of card stock, credit card, etc.
  4. After that I turn the piece so that the paper faced up and burnished it again to help it adhere.

Step 3: Trim the Foil & Fold the Shape

  1. trim off the foil that is over the edge of the card
  2. using the skewers make 4 holes in the foiled card. make these holes equidstant to each corner such as 1/2inch from each edge. it is ok to estimate :D, quick and dirty, right?
  3. insert skewer,
  4. shape the card to a estimated parabolic curve
  5. affix it with some adhesive to stop it from unfolding. I used blue poster tack.

Step 4: Setup and Results

You will want to place the card so that the deepest part of the curve is roughly 2.3 inches behind the monopole. For me I have a wall behind the router. You arrangement will require you to attach it in some fashion.

My results, I spent an extra 30 minutes noodling arund with the curve and I was able to get 3 to 4 dB attenuation behind the reflector (i.e. the nieghborhood) and 3 to 5 dB gain on the outer limits in front of the reflector.

your mileage may vary. good luck.


here are some links to more exacting reflector tuts:
http://www.binarywolf.com/249/signal_strength.htm
http://www.youtube.com/watch?v=YOBfxbpxosA&feature=related