To attach the high-gain antenna to the access point, you basically build a “chain” with four links in it: the access point, the pigtail, the antenna cable, and the antenna. (See Figure 4-10.) To attach the antenna to the access point, follow these steps. Assuming the access point is already working correctly, and you have good cables with the right connectors, these three steps should take just a few minutes. (We’ll talk more about the cables in a minute.)

Try using the Cantenna you built in Chapter 3 to boost gain on an access point. This antenna works as well on an access point as it does on a laptop computer.

Since you’re going to all the trouble of installing a high-gain antenna, you want to make sure that the access point uses it consistently. You configure this using the access point’s firmware. It takes just a minute or two. Here is a guideline for the process on a Linksys WAP11 or BEFW11S4 access point:

Figure 4-11 shows the Wireless tab in the Advanced section of the Linksys configuration program. In case you’re curious, the Default setting is a “diversity” setting, in which both antennas are active. Diversity Spread should automatically select the antenna with the strongest signal. However, since you know which one is always going to be the high-gain antenna, we’re choosing not to depend on the automated function.

Some access points transmit through only one antenna. Make sure you choose the correct antenna. Vendors tend to refrain from listing these engineering anomalies, so your best bet is to test the antenna after installation to make sure which transmit antenna works best.

If you have a Linksys WAP11 or BEFW11S4 access point, connecting your high-gain antenna to the access point is a snap, because these Linksys access points have detachable antennas. (Here’s where your opposable thumb comes in). Just grip the antenna base firmly between thumb and forefinger and turn counter-clockwise to remove. (See Figure 4-12.)

Other access points may not be so easy.We recommend an access point with external connectors and detachable antennas, because otherwise you may have to open up the access point, disconnect the existing antenna wires, and solder a new connector onto the wires—undoubtedly voiding any warranty in the process. Figure 4-13 shows a hard-wired antenna in a Cisco access point.

The other area where you might run into a slight hiccup is in building a pigtail to connect the access point to the antenna cable. The antenna side of the pigtail is no problem: Your antenna cable probably has standard female N-Connectors. So, to make the connection, the pigtail needs to have a standard, easy-to-find male N-Connector.

The male connector has a pin in the middle. The female connector has a socket. In addition, male connectors have threads on the inside of the connector body, while female connectors are threaded on the outside. (See Figure 4-14.)

The problem stems from the connector on the access point. The FCC mandated weird connectors for Wi-Fi antennas, because they were afraid that hobbyists would do things like connecting high-gain antennas to access points and possibly jack-up the power of their wireless networks beyond the legal limit. (Why would anybody want to do that?) They didn’t make it illegal to hook up a high-gain antenna, but they did try to ensure that you would use only antennas specifically designed for the wireless system. They did this by specifying connectors that you couldn’t find in your local Radio Shack, and which are incompatible with standard antenna connectors.

Linksys, for example, satisfies the weirdness requirement with reverse polarity (RP) TNC connectors. At first glance, Reverse Polarity (also called “Reverse Gender”) connectors look like normal male and female connectors. On closer inspection, however, you’ll find a major difference:

pigtail has to have a Reverse Polarity male (male body with a socket). Figure 4-15 shows RP-TNC connectors. Another common example is the reverse polarity SMA connector used on many D-Link products. Figure 4-16 shows RP-SMA connectors.

Don’t confuse RP with Reverse Threading (RT), which apparently also satisfies the weirdness requirement, and which refers to male bodies threaded to turn counter-clockwise to tighten, unlike normal male bodies, which turn clockwise to tighten. The FCC’s desire to thwart users wishing to attach standard antennas to Wi-Fi equipment has been less than entirely successful. However, the weirdness requirement has created a thriving pigtail industry, which you will now be supporting with a modest purchase (assuming you follow the advice in the next paragraph).

In Chapter 1, we recommended purchasing pre-configured pigtails for wireless client adapters, because of the hassle of soldering the tiny connectors needed to fit PC card connections. Buying pigtails is the easy way to go for access points as well. There aren’t any tiny PC card connectors to deal with. But you would probably have to special-order the RP connector for the pigtail anyway, so why not just go ahead and special-order the pigtail itself?