Wireless Hacks

Primestar Dish with Waveguide Feed

Use a cantenna waveguide in conjunction with a recycled satellite dish.

Primestar was recently purchased by Direct TV, who is now phasing out all the Primestar equipment. This means that the dishes are being trashed, and are available for other uses such as the one I describe here. It is easy to turn a surplus Primestar dish into a highly directional antenna for the very popular IEEE 802.11 wireless networking. The resulting antenna has about 22 dB of gain, and is fed with 50 ohm coaxial cable. Usually LMR400 or 9913 low-loss cable is used if the source is more than a few feet from the antenna. (See [Hack #62] for more details on cabling options.)

Figure 5-6 shows the Primestar dish in action.

Figure 5-6. Primestar dish on the roof.

To build your own, you’ll need the following parts and a couple of hours:

• A Primestar dish (you may use any old dish, but if it is bigger than the Primestar, the gain will be higher)

• A juice can (about 4 inches in diameter and at least 8 inches long)

• A chassis mount N connector

After deciding on a place to mount your antenna, remove the apparatus at the feed position of the dish. Be sure to save the mounting hardware. Using a can opener, cut one end of the juice can out, drink the juice, and wash the can out. Solder a quarter wavelength (1.15”) of wire onto the center conductor of the chassis mount N connector.

Using ...