Installing Antennas

Chances are that you won't have to install any antennas for your access points or NICs. Most come with antennas already attached and ready to go. However, if you purchased external antennas to increase the performance of your WLAN, you have to properly attach and position these.

Whenever you purchase an antenna for an AP or NIC, make sure that it has a compatible connector. Manufacturers use different connectors, so the best way to find a compatible antenna is to purchase it from the manufacturer that produced your device. Some of the common types of connectors are N, RP-SMA, RP-TNC, Lucent, BNC, and MMCX. The documentation for your AP or NIC tells you which kind of connector you need.

Insider insight: Professionals no longer refer to connectors as male and female, because some connectors have reversed versions available, also known as reversed gender, and more often, reversed polarity (RP). Normally a male connector would have a center pin like in coax cable for your cable TV box, and a female connector wouldn't. Reverse polarity connectors switch components between connectors, so a female connector might have the center pin from a male or vice-versa.

Plug and jack are the terms in use. The jack has no moving parts and the plug has active components such as a threaded rotating ring. Another way to distinguish the terms is to remember that the jack has the threaded rings on the outside of the barrel and the plug has the threaded rings on the inside of the barrel.

When you install an antenna, you also must check the maximum allowed cable length for the unit and antenna. A cable that's too long prevents the device from sending and receiving a radio signal. Different cables have different amounts of resistance to electrical current. Wi-Fi devices produce signals at varying strength, and some devices may not be able to operate with a longer cable because of the increased resistance. Do not exceed the maximum cable length listed in the documentation.

If you are installing an antenna outdoors, either to receive a signal from a fixed wireless service provider (WSP) or to extend the signal of your WLAN between buildings or to other parts of your property, you must take additional steps to protect your equipment.

Center pin:

The biggest threat comes from lightning strikes or damage from electrostatic discharge. You must properly ground an antenna, usually to the house's ground wire. You have to do this in accordance with building codes, so check with your local government. If this isn't done you risk damage from lightning strikes and from static (and you'll probably void the warranty on some of your equipment).

Caution: Grounding an antenna through a house's electrical system is a job for a trained electrician or professional installer. I don't care how much of a do-it-yourself sort of person you are, if you attempt to ground your antenna this way and you make a mistake, you will ruin your equipment and possibly kill yourself.

Simply grounding an antenna to a ground rod isn't sufficient to protect the system. The charge at the ground rod won't be equal to the charge at the equipment end (access point) and you will most likely damage your equipment

In an ungrounded system, a static electrical charge can build up from the atmosphere. This static charge can interfere with the WLAN signal and negatively affect the performance of your network. If you are experiencing static-related problems, you can manually ground the cable to discharge the static.

To discharge static on a cable, turn off power to the device and then disconnect the cable from it. Make sure that there is no power at either end of the cable, and then hold the cable in your hand and touch your thumb to the center pin. This discharges any static electrical charge through your body. You may then reattach the cable and restore power to the device.

Besides grounding your antenna, you should install a lightning surge protector between the antenna and the equipment indoors. This operates much like the surge protector for your PC; if the current suddenly spikes, a fuse blows in the unit and interrupts the circuit, stopping the current from reaching your equipment.