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This list of Frequently Asked Questions has been designed to be read from top to bottom with each question and answer increasing in complexity and assumes the previous answers have been read.
 
Q1 What does WiFi mean?
A1 WiFi is the popular term for a high-frequency wireless local area network (WLAN). It is also is a set of standards for wireless local area networks (WLAN) currently based on the IEEE 802.11 specifications to ensure interoperability of wireless networking products.
Q2 What is a WLAN?
A2 WLAN stands for Wireless Local Area Network. Wireless networks are made up of network adapters that transmit high frequency radio signals instead of using wires or cables to send information to other computers or devices on a network.
Q3 What equipment do I need to make a wireless network?
A3 In its most basic form a wireless network can be created by adding a wireless network adapter to 2 computers and setting them up in "Adhoc" mode.
More commonly used however, is a wireless router or access point which controls the flow or "routs" the information being sent around the network with wireless network adapters being added to each computer on the network, these computers connecting to the access point are called clients.
Q4 How far can a WLAN reach?
A4 Manufacturers of domestic grade products typically rate their equipment to reach approximately 40m indoors and around 100m outdoors. These ratings however are based upon "average" conditions and as such may not be a reliable indication for individual network coverage.
The best way to guess how far your wireless network will reach is by imagining the network in a similar perspective as your mobile and cordless telephones. The distance and quality of connection will vary according to both physical and electromagnetic interference.
Q5 What constitutes Physical and Electromagnetic interference?
A5 Physical interference is anything you can physically touch - walls, people, computers etc, even clear substances such as water and glass greatly affect the strength and quality of the signal used for wireless networks.
Electromagnetic interference is any electrical signal on or near the same frequency that wireless networks operate. Interference can also be caused by signals not on or near the same frequency but strong enough to drown out the signals from your wireless network.
Q6 What can I do about interference?
A6 There are 2 things you can do to overcome interference, eliminate and overpower-

i) Eliminate interference by moving your access point to a central location within your network thus reducing the amount of interference between each point.
ii) Overpower the interference by increasing each transmitters' signal transmit and power and receive sensitivity.

Imagine you are trying to have a conversation with another person 2 bedrooms away. You are the access point and they are another computer (client). You are having trouble hearing each other and there is a lot of "what did you say?" going on so your conversation is slowed down to communicating at about 1 complete sentence a minute. In network terms lets say 1mb/s. At this point your dog starts barking (cordless phone radio interference) and you cant achieve 1mb/s - windows at this point will probably inform your friend 2 rooms away that they are unable to connect to the network - your conversation has been terminated.
You can move into the next room adjacent to your friend and that may be enough to reconnect to the network.

Changing rooms may not be an option because you also need to communicate with someone else in the opposite direction and changing rooms may result in not being able to establish communication with them. In this case you need to talk louder and listen harder by increasing your signal strength (loudness) and listening harder.

Q7 Am I able to increase a transmitters signal strength and receive sensitivity?
A7 You cannot increase a transmitters signal strength or sensitivity unless it is an option the manufacturer offers in the equipments settings. This option however is extremely uncommon so the realistic option is to modify or focus the signal after it has left the unit, this is done through the use of antennas.

All wireless networking equipment uses an antenna to transmit and receive signals in one form or another. Some antennas are internal whilst others are external. When the antenna is internal there is nothing you can do to modify the signal short of physically pulling the unit apart.
For units with external antennas some are detachable, in these cases you are able to remove the original antenna and attach another antenna in its place. The replacement antenna used could be one that concentrates a signal or focuses the direction in which it transmits and receives, would effectively improve the units transmit and receive ability in those directions.

Q8 How do antennas increase signal strength?
A8 Antennas work in both directions, transmit (TX) and receive (RX). When a signal is pushed into the base of the antenna from the transmitting unit, the signal is converted into radio waves or (RF). An antenna in its simplest form can be as simple as a straight length of bare metal in which case the RF signal leaving it would be uncontrolled and unfocused. The radio waves emitted from the antenna if you could see them would form a shape like a sphere in all directions, this shape is called the radiation pattern. RF engineers design antennas to take the available signal being pushed into the antenna and focusing its energy into given directions thus providing gain measured in dB. As the antenna is used for both transmit and receive the gain works in both directions, signals already in the air coming from the directions the antenna has been designed to concentrate on be louder when going back into the receiver and signals coming from outside of the concentration areas will be quieter. The higher the gain in the antenna the more focused will be its transmit radiation pattern and also its receive sensitivity.
Q9 How do I pick an antenna that is right for me?
A9 When choosing an antenna it is vitally important to know the physical layout of the network and the potential interference that will cause connectivity issues. The location of the central access point, the clients and interference points will be the determining factor for the antenna requirements. You should always conduct a site survey of the proposed WLAN using test equipment that measures signal strengths and interference levels at all access point and client locations before purchasing products.
Q10 I have a wireless router with a removable antenna.
I canít seem to pick up the signal with my laptop when I go outside.
Will the WTR-2407 do the job. The D-link WDL-50AT is a 5db and it says it can do up to 500 meters?
A10 The reason for the laptop not connecting to the router is interference. The WTR-2407 will increase the signal power and receive sensitivity of the wireless router by 7db. Without conducting a site survey of the WLAN it is impossible for us to tell you the degree of improvement to the laptop's range to the router. For best results you should also attach a WTR-2407 antenna to the laptop and move the router away from other transmitting devices.