A 15 Element Yagi Wi-Fi Antenna (Part 2)

High Building, mounting, and testing for long range connectivity.

This antenna can be constructed in a couple of hours and some measuring, cutting, bending, and bolting metal. Use caution around the sharp edges. When finished, put it up and enjoy a very durable antenna that provides great signals.

YAGI WIRELESS ANTENNA PARTS LIST:

1. A one meter length of 14 AWG bare, solid copper wire.
2. One wooden square, 1 cm per side, 50 cm long.
3. Wire cutters.
4. Metric ruler.
5. Drill, with 1.6 mm (1/16") bit.
6. Printed or written template with antenna dimensions.
7. Ball point pen or fine felt tipped marker.

YAGI WIRELESS ANTENNA CONSTRUCTION:

Building the yagi wifi antenna wil now continue, with preparation of the boom, followed by element mounting. After the elements are mounted, a suitable connector is added, and the antenna is tested over-the-air.

1. Draw a line as accurately as possible down the center of one side of the wooden boom.
2. Mark the boom centerline 5 cm from one end. This is the "zero" station, where the director element will be mounted.
3. Continue down the boom, carefully marking the locations of each element on the centerline.
4. Carefully drill through the boom at each element's location. Make sure to drill straight through the boom, emerging on the other side still centered.
5. Cut one element at a time, carefully measuring each element before and after cutting, trimming as necessary for proper length.
6. Press elements through the boom, centering each before moving to the next element.

7. For the driven element, cut a 130 mm length of wire, and make a 180 degree bend 30 mm from one end. Mount in boom, then make a bend 30 mm from other end. Adjust as necessary to create a folded dipole just under 59 mm in length with 5 mm spacing.
8. Double check all elements, making sure all are centered and parallel.
9. Attach a pigtail (or connector) to open ends of folded dipole.

After all of the elements are measured, cut, and mounted, the antenna should resemble the finished yagi pictured below. Connect the pigtail or connector to the driven element. Then connect the woreless device to the antenna and start checking over-the-air signal strengths. Note that the antenna may be sensitive to polarization: when the antenna seems to bring in the best signal, rotate it to find the best polarization. Mounting the antenna is possible using commonly available hardware, such as 90 degree angle brackets, U bolts, or even velcro.

YAGI WIRELESS ANTENNA TESTING:

For the most practical method of signal checking, consider using a wifi auditing utility such as Kismet, Airodump, or Netstumbler. Any of these will produce a rapidly updated received signal strength indication that is useful for comparing or aiming 802.11 directional antennas. Make a set of measurements for any desired wifi access points on the original antenna, then make a new set for the yagi wi-fi antenna.

The antenna should exhibit good forward gain and front-to-back ratio. A prototype in fact performed as well as the 12 turn helical shown elsewhere in these pages. Indeed, the antenna exhibits near the theoretical 15 db gain, enabled broadband connections at 54 MB/S over a path that at best reached 11 MB/S on an unmodified wifi adapter. Again, for ultimate performance over long distance wi-fi links, use a short version of the yagi to feed a parabolic reflector.

Good luck building the yagi wi-fi antenna, and may you enjoy solid long range connections!

Prior Steps