Monday, February 17, 2014

Troubleshooting: Wireless Network Antennas

In a previous article I talked about a software tool for troubleshooting problems with a wireless network signal.  This article focuses on the antenna and related technologies.  I will do my best to keep the subject matter of this article so that its understandable.  Although, the terminologies and concepts can quickly become confusing.

When troubleshooting a wireless network problem, it’s important to have a good understanding of the basic technology in order to solve problems with it.  One of the primary components of any wireless network is the antenna.

The primary antenna issue with most wireless networks is the range of the signal.  To help extend the range of the WiFi device, there are a few things that can be done.

  • Try moving the WAP to a new location.  Ideally it should be centrally located in a structure, unless you're broadcasting the signal between two points.
  • Try to create one of the many DIY wireless signal enhancers that are available on the Internet (see the reference area below).
  • Buy a better antenna for the WAP or wireless network card (if the device supports this option).
    • Note: there are a few different types of common antenna connectors
  • Buy a WiFi signal booster/extender/repeater to extend the range of the signal.  There are a few different types of these devices, research will be needed to find the one that will best meet the requirements of the network.
    • Note: If considering a high-power antenna or some type of signal booster, the FCC limits the maximum transmission power to 1 watt, or about 36 dB.

There are some important terms to know about WiFi networking to have a greater understanding of the technology:

  • 802.11: The international wireless networking protocol standard.  There are currently six versions of this protocol (801.11/b/a/g/n/ac).  Each version of the protocol is faster then the previous.
  • Attenuation: The loss or weakening of a signal through its transmission.
  • Direction: There are generally two types of antennas: unidirectional (one direction) and omni-directional (all directions).  Unidirectional antennas are for point-to-point communication.  Omni-directional antennas are for point-to-multipoint communication.
  • Frequency: The two main frequencies that are used in 802.11 wireless networking are: 2.4GHz and 5GHz.  The 2.4GHz frequency is the most popular, and often the noisiest.
  • Gain: A measurement of the antenna's signal and typically measured in dB (decibels).
Additional Resources:
  • DIY WiFi Antenna booster: Ez-12 Parabolic Reflector Template
  • When buying a new antenna for a wireless device, there are few basic types of 802.11 antennas.  Depending on the wireless network setup, some of these may be able to help boost the signal or range.
    • Parabolic: supports a unidirectional signal, can look like a satellite dish.  Generally used for sending a signal between two specific points.
    • Yagi: supports a unidirectional signal, the core antenna can be covered with a plastic tubular housing (it can also look like an older style TV antenna).  Like a Parabolic antenna its used for sending a signal between two specific points.
    • Dipole: omni-directional signal (signal goes in all directions).  This is the most common WiFi antenna, it can cover a wide area (generally a few hundred feet), but wastes a lot of energy because the signal radiates in all directions.

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