What is all this foolery
about? To begin with, this is
entirely copied from
this guy over at O'reilly.
Basically, I printed off his page and used it as a shopping list and
construction kit. My only addition is the excessive use of hot glue to hold the
thing together. What we have here is an antenna for 802.11b wireless Ethernet.
Antenna's and/or dishes for the 2.4GHz spectrum generally run about $150 or so
(And that's on the low end, you can get real crazy if you wanted too). Some cool
guys out there have been playing with cheap hardware that produces about the
same amount of gain as the professional hardware gets. Yes, this is how to build
a respectable 2.4GHz antenna for about $4 in parts. The most expensive thing was
the pigtail that has Orinoco's funky connector on one end and a nice N-connector
on the other end (Which was $25 with S/H). I paid $1.50 for a female N-connector, $1.69 for the
Pringles, and like a buck for the all-thread, washers and nuts.
I really think
Afrotech is wearing off on me! I would have
built this thing properly, but I had trouble finding all the parts I needed,
namely some narrow tubing and 1" washers with 1/8" holes in them. (Or, the first
hardware store I went too didn't have everything I needed and I was too lazy to
try somewhere else). Anyway, I used hot glue to hold the washers in place as
well as holding the N-connector in place. From what I have read about Yagi-Uda
style antenna's, the washers don't need to be electrically connected to the rod,
so that aspect of this antenna is still ok. It's just that the washers aren't
all 100% at the same angle on the all-thread because the center hole in them is
too big. I got a solid 5dBm gain; for 45
minutes of work and no tuning it's amazing it works at all! :-) So here
are my pictures of the event, as well as some screen grabs of Netstumbler
showing my signal strength levels.
Oh yea, do this at your own
risk- so now you can't say I told you to do it and sue me. You
may/might/could/probably/will/defiantly/wont blow up your wireless card if
you do this wrong.
As far as the actual
design, I have read that the foil in the Pringles can is too thin to actually
function as a wave guide, so all you are really using is the bottom tin plate to
reflect the signal onto the antenna wire, or something like that. I'm certainly
not an RF engineer, so this is only speculation and hearsay. Check out the
Netstumbler forums for some excellent discussion of antenna design and links to
good sites like
The starting point. Why the Pot Pie you
ask? You shall see very soon... Actually I needed a way to space the washers
apart while I was gluing them. The I needed something to fit around the hot glue
holding the last washer on at the same time, so some thin card board was the
answer. Finally my way of cooking is paying off!
A close-up view of the assembly
A fully glued assembly. Now it just
needs some lids to hold it in the center of the can. I used the bottom of a
Country Crock mini-tub since I didn't have another can of Pringles on hand.
Assembly and the hole for the
I used some braided copper wire for the
"fuse". I could have left the insulation on it I guess, I just thought this
looked cooler :-).
N-connector mounted securely
I ordered my pigtail off the internet as
I couldn't find a local source for those funky little Orinoco connectors. My
local electronics shop is generally good, but they don't get out much when it
comes to new connectors...
Male pigtail connector and female card
Another lovely picture of my card
And how it preformed
I sat outside on a bench and used my AP
for reference. This only shows an overall gain of about 5dBm, but you will also
notice the signal-to-noise ratio improve by 5dBm as well. I actually plan to
make some more antenna's soon that should pull in more signal... We shall see!