Tuesday 25 October 2011

Three Things to Know When Choosing Antenna


Three Things to Know When Choosing Antenna
As the most visible part of wireless equipment, it’s important to know a little bit about antennae when choosing a system. Just to get everyone on the same page, an antenna is designed to transmit and receive clear signals between multiple points. This can be from your wireless router to your laptop, from a laptop to a printer, or any other of a wide variety of applications. For any wireless network to work quickly and efficiently, an antenna is a requirement. And just as there are different types of wireless setups, there are different antennas for different purposes. As such, when choosing your model, it’s important to understand the three key specifications: frequency, beam width, and gain. 
Frequency is described as the data transmission between two points via electronic waves that carry kinetic energy. The associated energy of the wave is directly proportional to the wave’s frequency. Frequency is represented by the equation E=hv where v=frequency and h=Planck’s constant, which is 6.626 x 10-34 J s. Therefore, the higher the frequency, the more kinetic energy the wave carries, and the more powerful the wave.

Gain refers to the measure of the ability to amplify incoming signals. The value of the gain directly correlates to the antenna’s receiving strength. It is measured in dB, a function of the capture area and reception/transmission frequency. A larger antenna with a greater capture area has higher gain values, as do ones at higher frequencies. Wide area networks, such as those where data is sent over longer distances, need antennae with higher gain ratings (10+). In a smaller area or smaller room, lower gain works just fine.

The beam width is the area in which the signal is received and is usually measured to ½ power points. This refers to the number of degrees between the points where gain is 3dB less than the gain for the antenna’s strongest direction. The higher the gain, the lower the beam width. Increased gain with a decreased beam width receives signal over a smaller area but offers a strong signal. By contrast, less gain increases the beam width, which receives the signal over a larger area but at a weaker strength.  Beam width is measured in two planes, vertical and horizontal.

While these are three key factors to understand, a search for an antenna may also introduce you to “OMNI”. OMNI is especially powerful, versatile, and useful for 360 degree beam width in one plane or another. As a result, the antenna is capable of signal reception and transmission in all directions on that particular plane.

Beam width is an important factor in antenna placement. If the unit will be mounted on or against a wall, you don’t need the beam width to cover the wall part of the horizontal plane. The same is true when the device is mounted on the ceiling or the ground. When antennas are used to transfer signal from roof to roof, you must mount it so the beam widths of the two receivers intersect. And finally, if you plan on using it in the center of a wireless network, OMNI is the way to go.

With antenna, there are many types available along with myriad placement configurations. This gives you huge flexibility and creativity in building your own wireless network. Whether for home or professional use, choosing the correct antenna for your needs based on these three factors will help you achieve the results you’re looking for.

Tuesday 18 October 2011

All About Couplers and How to Choose Them

Whether you are setting up a new stereo or computer system, it can be frustrating to discover that the cords don’t connect correctly. Attempting to fix this problem will probably have you looking for a coupler. However, that can be even more confusing. And for good reason, too. With the vast amount of cable styles available, there needs to be at least as many couplers in order to connect them all. Couplers exist solely to connect a single pair of cables. Here are a few of the common questions surrounding couplers and a little bit of information on how to find the right one for your needs.
First, you’ll need to know the difference between straight and crossover connections. Straight connections are made directly from pin to pin. When you use a network hub and switch, these are the types of connectors you’ll need. Straight cables connect electronic devices right to the hub or switch you’re using. By contrast, crossover cables are used to connect devices to each other. If you try to connect them directly, without a hub or switch, the signals will be mismatched since both will transmit and receive simultaneously. Each device will attempt to send output to the other’s output, which will completely mix up the signals. A crossover cable connects the right pins together, even when they are organized differently. If you take a close look at the two cables, you’ll see that the colored wires are in a different order on each. The crossover connector untangles the signals so that the information is sent and received properly. Therefore, crossover couplers can connect two straight cables.
Next, you might be interested to know what a reverse coupler does. Reverse couplers work similarly to a crossover coupler. However, instead of crisscrossed wires, the two connections will have the same color wires only in a reverse order, not all mixed up. This type is used for telephone connections.
Another confusing detail is shielded and non-shielded couplers. Shielded ones decrease the interference from other outside devices. The more peripheral devices there are, the higher the chance that interference will be a problem. 
Finally, one last option you’ll see is both printed and non-printed circuit board couplers. This is another technique used to reduce interference; only this style looks at internal, not external, noise.  Both CAT-5 and CAT-6 couplers utilize printed circuit boards. Printed circuit boards use a crisscrossed technique of wiring the board to decrease the amount of internal interference.
So how does this affect you? First, it’s important to determine which type of cables you need to connect. There is a good chance you can find this information in the user’s manual of the devices you’re trying to connect. Short of that, you can physically look at the wires within the cables themselves. With Ethernet, the clear connector on the end allows you to clearly see the wire coloring. You’ll need a coupler that has an end matching each device. And don’t allow the vast selection to scare you off. With so many choices out there, you can guarantee that there’s a coupler that will work for you.