Brooke Yan asked:


A network allows a single broadband account to be shared throughout the home. Unfortunately, such networking is impractical with dial-up Internet service–one of several reasons you might want to consider broadband.

WHAT’S AVAILABLE

Home networking is getting a boost from improvements in the range, speed, and cost of wireless networks. If you own a laptop computer that has wireless capability, a wireless network now allows you to surf the Web at broadband speeds from most places in your house, yard, or apartment. Leading brands of wireless routers include D-Link, Netgear, and Linksys. Wired networking is far from obsolete, however, since it still provides the most secure and reliable connections. Indeed, for many households the best solution for sharing a broadband connection–or a printer, music files, or digital photos–among multiple computers might be a network that includes both wired and wireless.

Ethernet, or wired, networks. Wired networks are very secure by themselves, with no special security measures necessary. They are reliable, and usually immune to interference. They offer the fastest data transfer–up to 94 megabits per second for the common 10/100 type, enough for virtually any data application.

IMPORTANT FEATURES

One drawback is that you can’t easily move your computer around the home. Routing cables throughout the home can be a hassle or expensive. Price range: $50 to $100 for one router and a cable to connect two fairly new computers. Also, there might be additional costs for routing cable through the home. Wi-Fi, 802.11g (wireless). There are no cables to connect or rout with a wireless network, and there are minimal installation costs. Mobility is the key–the wireless network supplies signals virtually anywhere around the home. You will need to take additional steps in terms of security, without which your data are vulnerable to hackers. Thick walls can reduce signal strength, which might vary in different areas of the home or even within a room. Wi-Fi networks might interfere with cordless phones, baby monitors, and other wireless devices. These networks are only 25 percent as fast as Ethernet, but they’re still fine for typical networking uses, such as Web surfing and e-mail. Price range: $200 or less for a router and client cards to allow two computers to use the network wirelessly

HOW TO CHOOSE

Plan your network. You’ll probably want to locate the router near the source of your broadband service–usually a cable or DSL modem. The router and the modem will be connected by an Ethernet cable. But the connections between the router and the computers in the network might be either wired or wireless.

Choose a wireless router. That is the official term for the models that support both Ethernet and Wi-Fi. Even if you don’t need wireless capability now, acquiring it costs little extra (perhaps $10 or so) compared with a wired model, and might spare your having to replace the router if you want to add a wireless device to it in the future.

Stick with the 802.11g wireless standard. Wi-Fi is continually evolving, with new standards designed to increase broadcast range and speed, thus increasing the network’s ability to handle new types of information. The name of the standard is usually listed on the router’s package, as a letter suffix to the technical term for Wi-Fi, which is 802.11. Currently the most common standard is known as 802.11g. We think it’s the best choice for most people.

The 802.11g networks we tested all had sufficient range and speed to provide coverage throughout most homes. The data speeds we measured fell short of the standard speed for 802.11g. But all routers were much faster than the typical speed of a broadband Internet connection.

If you already have a wireless network that uses 802.11a or 802.11b, two older standards, consider upgrading only if you find the range, speed, or reliability of your network wanting.

At the other end of the spectrum are routers that use early variants of the latest Wi-Fi standard, 802.11n. Frequently referred to with terms such as “MIMO,” “Super G,” or “pre-n,” such models might not be compatible with the actual “n” standard, which is due in late 2006. They also require that you buy matching networking adapters, even for computers with built-in 802.11g capability.

Consider one of these new routers only if you have range problems that can’t be solved in other ways. In our tests, they were better at penetrating walls than 802.11g routers, and some offered data speeds that were twice as fast. But they were just as likely to interfere with (or receive interference from) cordless phones and other devices.

Consider whether and how you’ll share a printer. A network lets you avoid the cost of putting a printer in every room by sharing one. To do this, you can use a printer with built-in network capability.

It’s possible to share a non-networked printer by attaching it to the network via a print server, a device that costs $70 to $100 and is the size of a large paperback. There may be issues of interference with some printer-management software, however. Any PC connected to a printer can also serve as a print server for the other computers on the network, though you must leave that computer on when you’re printing.

Consider networking issues for other devices. An increasing number of devices that typically connect to a single computer–PDAs, printers, and video-game consoles–are now Wi-Fi compatible. If you plan to connect any of them to your network, make sure they’re compatible with the network security you set up.

Check whether you need to buy adapters. Every computer on your network will require an adapter to allow it to communicate with the network; the question is whether it already has one built in. If you’re using Ethernet to connect a computer bought within the past three years or so, the adapter will most likely be built into the unit. The same applies to recent-vintage laptops, which should have built-in 802.11g capability.

If you need to buy a network adapter for your desktop, you can choose either an internal PC-card version, which requires opening the computer case for installation, or a USB version, which plugs into a USB port. Laptops can use either a PCI-card or USB adapter. In all cases, the cost should be no more than $60.

Resist professional installation help. Computer retailers might try to sell you on professional installation for your new network, starting at a cost of $150 or so. But wiring aside, today’s networks are so easy to set up that you shouldn’t take them up on their offer if you’re comfortable with technology.

Network gear usually comes with instructions and access to free 24/7 technical support. And you can always come back to the retailer for help in troubleshooting the network if necessary.

Shop by return policy. For all your best efforts, the network equipment you’ve bought might not be compatible with your home. For example, your walls and floors might be especially resistant to wireless transmission (which might be the case if they have a lot of moisture, metal, or other highly conductive material in them). Before you buy, check the store’s return policies. Consider a retailer with a generous one.

Copyright © 2002-2006 Consumers Union of U.S., Inc.

For the latest information on this and many other products and services, visit www.ConsumerReports.org.

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Steve asked:


The services that you had always wanted to provide to your cherished customers are now available at no extra cost. There are firms that allow you to provide free or paid for internet services on wi-fi hotspot gateway to your customers. These companies also allow you to make the wi-fi zone available to the customers with your own branding. On top of that they also allow you to provide these services without paying any money to the service provider. In fact there is no need to sign up for any revenue sharing or monthly charging schemes with the service provider.

All this has made the job of providing the internet services to your customers on the wi-fi hotspot gateway all the more easier and interesting. It doesn’t matter whether you are a small time coffee shop owner or running an internet café. Various kinds of wireless hotspot gateway services are available that would suit the kind of internet service you wish to provide to your customers. There are hotspot gateway services that take the visitor to the landing page on which your brand name is displayed and the customer is then provided with the free internet access for a limited or an unlimited duration.

There are wi-fi hotspot gateways available in which software is made available to the service provider that can store thousands of unique five letter codes that can be sold to the customers as internet access tickets. These kind of wi-fi hotspot gateways are used by the people who run internet cafes. Another type of wi-fi hotspot gateway that is used by many small time coffee shop owners is the one in which a single code is used by many visitors.

steve asked:


Expensive RF analysis tools are available to measure a variety of parameters that only an RF engineer has a clue what they mean and the implications of their values. But when it comes to networks — wired or wireless — ultimately, what one should be most interested in is throughput performance. 802.11 (i.e. Wi-Fi) is a robust standard that includes a variety of protocols that help it communicate wirelessly with other devices. Unless one has intimate knowledge of the 802.11 standard and its inner workings, then it is not possible to predict how an 802.11 network will behave when you are armed solely with RF measurements. This is why it is important to focus on performance metrics — since these more accurately predict how a wireless network will actually behave in a real-world environment.

What follows is a brief introduction to 4 troubleshooting techniques (network discovery, RF spectrum analysis, WiFi channel analysis, and WiFi connection analysis). We begin with a summary of the pros and cons of the different troubleshooting techniques, which should give you a high-level view of the direction in which the field of WiFi diagnostics is currently headed:

Summary:

1. Network Discovery:

Advantages: Inexpensive

Disadvantages: Of limited use since it only detects beacon packets transmitted by 802.11 access points. It does not “see” or measure RF energy transmitted by non-802.11 devices (which dominate the RF environment) or, even, actively transmitting 802.11 stations.

2. RF Spectrum Analysis:

Advantages: Detects all RF transmissions within a frequency band. Based on the transmission pattern you might be able to identify the source of the interference.

Disadvantages: Expensive — since it requires proprietary hardware. When it detects RF interference in the 2.4x or 5.x GHz ISM bands, it can not predict how this will affect 802.11 devices or WiFi network performance — since it knows nothing about the 802.11 standard nor how its underlying protocols work to mitigate potential sources of interference.

3. WiFi Channel Analysis:

Advantages: Inexpensive — uses off-the-shelf 802.11 devices. Measures RF interference through the eyes of an 802.11 device — hence, can better predict how an 802.11 Wi-Fi network will actually perform in the current environment. Can quantify the expected performance for each Wi-Fi channel, thereby allowing you to choose the optimal channel.

Disadvantages: Of limited use when attempting to identify the source of interference.

4. Connection Analysis:

Advantages: Inexpensive — uses off-the-shelf 802.11 devices or your built-in 802.11 adapters. Measures throughput performance of your 802.11 devices when connected to a Wi-Fi network — which is the ultimate metric when it comes to troubleshooting a network.

Disadvantages: Of limited use when attempting to identify the source of interference.

——————————————————————————————-

Descriptions:

1. Network Discovery An 802.11 network discovery tool will report the Service Set Identifier (SSID) for each access point (AP) it detects, along with the channel used by the AP. Approximately every 100 mSec an AP transmits a small beacon packet and a discovery tool (running on your laptop and using its 802.11 wireless adapter) detects the beacon and adds the packet information (including the AP’s SSID) to its list of known access points. In addition, the discovery utility may report signal strength (in dBm units) of the beacon as detected by the client adapter. The beacon’s signal strength is a reflection of how close the AP is to your current location. Though this is useful information, it does not tell you anything about non-802.11 devices or even how busy the access points are. That is, your laptop could be sitting next to a microwave oven and the discovery tool would be clueless as to its existence. The discovery tool only knows about beacon packets transmitted by 802.11 devices and can not see non-802.11 transmissions.

Network discovery tools use the 802.11 adapter built into your laptop or an external USB 802.11 adapter. Since they do not require additional proprietary hardware, then they are relatively inexpensive (even free).

AP Beacon Strength Is Not A Measure Of Performance

The signal strength reported by a network discovery tool is the signal strength of a beacon as measured by the 802.11 wireless adapter installed on your laptop or desktop machine. Each access point (AP) sends out a short pulse or beacon of information approximately every 100 mSec. It’s equivalent to an ‘I’m over here!’ shout. It does not expect a response from the 802.11 client adapters that may hear it — it’s just a one-way shout. The signal strength that the network discovery tool reports is the signal strength of a beacon, and the signal strength of a beacon is a reflection of how close that AP is located to you. It is not a reflection of the performance or throughput you can expect by associating with that AP — rather, it is an indication of the AP’s physical location relative to you. If the AP with the strongest beacon has 24 client adapters associated with it that are actively transmitting and receiving information, and if you connect with that AP then you will be client number 25 and your network connection will seem slow. On the other hand, if you instead choose to associate with an AP whose beacon strength is weaker but which is not associated with other client adapters, then you will likely experience better performance. Furthermore, the AP with the strongest beacon signal may be using a channel that is subject to RF interference — again, degrading its performance. When it comes to networking (both wired and wireless) what we care most about is performance. And the key to performance is ‘throughput’ (i.e. bytes-per-second). Though a beacon’s signal strength can affect it’s performance, what’s more important is the number of client stations that are competing for the same AP and whether the channel currently used by the AP is subject to RF interference from other wireless devices in the vicinity.

2. RF Spectrum Analysis An RF spectrum analyzer is the instrument of choice for detecting and identifying sources of RF interference. Spectrum analyzers are a basic tool used for observing radio frequency (RF) signals. Since they detect all RF transmissions (both 802.11 and non-802.11) then they provide a much better picture of the RF environment, which then helps you identify and, perhaps, locate devices that could be interfering with your Wi-Fi network. Typically an RF spectrum analyzer will employ a 2-dimensional display where the vertical axis (Y-axis) represents the strength of a signal and the horizontal axis (X-axis) represents the frequency of a signal. If the spectral trace of the interfering RF transmissions have previously been documented, then it might be possible to determine which type of device is causing the disturbance. As for tracking-down and attempting to locate an interferer, in practice this is more difficult than it might seem on the surface. Not only does it require the use of a directional antenna, but in an indoor environment with waves bouncing all over the place (off of objects and walls) then how do you discern from which direction the wave originated. In other words, when your directional antenna measures a signal from a wave you don’t know whether that’s the original wave or the result of a wave that has bounced off of an object or wall in the room.

3. WiFi Channel Analysis Today, one of the hottest topics discussed by Wi-Fi infrastructure manufacturers is “using the infrastructure to troubleshoot the infrastructure”. That is — using 802.11 devices to troubleshoot an 802.11 network. Channel analysis is a new technique we have championed and pioneered. This type of tool uses 802.11 hardware to perform data acquisition — hence, the results truly reflect how RF interference in the local environment affects throughput performance of 802.11 channels. This is not possible using an RF spectrum analyzer. By virtue of the fact an 802.11 channel analyzer views the RF world through the eyes of an 802.11 device, then the diagnostic information it provides more closely mirrors the performance you can expect from your own 802.11 client adapters. This makes it easier to troubleshoot and fix problems and allows you to make better-informed decisions regarding how best to configure your wireless network for optimal throughput performance.

4. Connection Analysis Ultimately, the bottom line for any network (wired or wireless) comes down to throughput performance — that is, how many bytes-per-sec can be transferred from one node on the network to another. The dBm and RSSI values that are often referred to in the context of wireless networks don’t mean much if you can’t somehow relate them to a performance metric. Before we can really begin to troubleshoot a wireless network we need a way to benchmark its performance, so as modifications are made we can determine whether or not they really make a difference in the network’s performance. A connection analysis tool allows you to directly compare the performance and reliability of different combinations of 802.11 adapters and access points.

Mangesh A. Dahale asked:


The IEEE 802.11 working group published the 802.11 standard for wireless LANs in 1999. 802.11b is a supplement to 802.11 that specifies a higher data rate and is currently the industry-accepted standard for WLANs. 802.11b products that meet a base standard of interoperability are certified by the Wireless Ethernet Compatibility Alliance (WECA) with the Wi-Fi™ logo. Several IEEE 802.11 working groups are creating standards for improvements in data rates, quality of service, and security.

Wi-Fi is not a fully wireless LAN. It is an extension to the existing wired network. By using device called Access Point (AP) wireless nodes can be connected to the wired network. Otherwise wireless nodes has to be connected in AdHoc style. Its typical coverage area is 100 to 500 feet.

Wireless LANs give the enterprise more mobility and flexibility by allowing workers to stay connected to the Internet and to the network as they roam from one coverage area to another. This increases efficiency by allowing data to be entered and accessed on site.

In September of 1999, the Institute of Electrical and Electronic engineers (IEEE) ratified the specification for IEEE 802.11b, also known as Wi-Fi. IEEE 802.11b defines the physical layer and media access control (MAC) sublayer for communications across a shared, wireless local area network (WLAN).

At the physical layer, IEEE 802.11b operates at the radio frequency of 2.45-gigahertz (GHz) with a maximum bit rate of 11 Mbps. It uses the direct sequence spread spectrum (DSSS) transmission technique. At the MAC sublayer of the Data Link layer, 802.11b uses the carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol.

A wireless station with a frame to transmit first listens on the wireless medium to determine if another station is currently transmitting (this is the carrier sense portion of CSMA/CA). If the medium is being used, the wireless station calculates a random backoff delay. Only after the random backoff delay elapses can the wireless station again listen for a transmitting station. By instituting a random backoff delay, multiple stations that are waiting to transmit do not end up trying to transmit at the same time (this is the collision avoidance portion of CSMA/CA).

Collisions can occur and, unlike with Ethernet, they might not be detected by the transmitting nodes. Therefore, 802.11b uses a Request to Send (RTS)/Clear to Send (CTS) protocol with an Acknowledgment (ACK) signal to ensure that a frame is successfully transmitted and received.

Wi-Fi wireless networking consists of the following components:

1. Stations

2. Wireless Access Points

3. Ports

STATIONS (STA)

A station (STA) is a network node that is equipped with a wireless network device. A personal computer with a wireless network adapter is known as a wireless client. Wireless clients can communicate directly with each other or through a wireless access point (AP). Wireless clients are mobile.

Wireless Access points (AP)

A wireless AP is a wireless network node that acts as a bridge between stations and a wired network. A wireless AP contains:

1. At least one interface that connects the wireless AP to an existing wired network (such as an Ethernet backbone).

2. A wireless network device with which it creates wireless connections with stations.

3. IEEE 802.1D bridging software, so that it can act as a transparent bridge between the wireless and wired networks.

The wireless AP is similar to a cellular phone network’s base station. Wireless clients communicate with both the wired network and other wireless clients through the wireless AP. Wireless APs are not mobile and act as peripheral bridge devices that extend a wired network.

PORTS

A port is a channel of a device that can support a single point-to-point connection. For IEEE 802.11b, a port is an association, a logical entity over which a single wireless connection is made. A typical wireless client with a single wireless network adapter has one port and can support only one wireless connection. A typical wireless AP has multiple ports and can simultaneously support multiple wireless connections. The logical connection between a port on the wireless client and the port on a wireless AP is a point-to-point bridged LAN segment similar to an Ethernet-based network client that is connected to an Ethernet switch.

HOW IT WORKS?

When a wireless adapter is turned on, it begins to scan across the wireless frequencies for wireless APs and other wireless clients in AdHoc mode. Assuming that the wireless client is configured to operate in infrastructure mode, the wireless adapter chooses a wireless AP with which to connect. This selection is made automatically by using a SSID and signal strength and frame error rate information. Next, the wireless adapter switches to the assigned channel of the selected wireless AP and negotiates the use of a port. This is known as establishing an association.

If the signal strength of the wireless AP is too low, the error rate too high, or if instructed by the operating system (in the case of Windows XP), the wireless adapter scans for other wireless APs to determine whether a different wireless AP can provide a stronger signal or lower error rate. If such a wireless AP is located, the wireless adapter switches to the channel of that wireless AP and negotiates the use of a port. This is known as Reassociation.

Reassociation with a different wireless AP can occur for several reasons. The signal can weaken as either the wireless adapter moves away from the wireless AP or the wireless AP becomes congested with too much traffic or interference. By switching to another wireless AP, the wireless adapter can distribute the load to other wireless APs, increasing the performance for other wireless clients. You can achieve contiguous coverage over large areas by placing your wireless APs so that their signal areas overlap slightly. As a wireless client roams across different signal areas, it can associate and reassociate from one wireless AP to another, maintaining a continuous logical connection to the wired network. It communicates with the AP using Direct Sequence Spread Spectrum (DSSS) technique.

jackdrogba asked:


As you know, to achieve desktop and notebook computers “wireless”, as long as desktop and notebook computers have a wireless card on-line ,2-n wireless network adapter card can be composed of blocks of a multi-agency into the Ad-Hoc Wireless peer networks to achieve Networking playing games and sharing online.

Currently at the university campus, the hotel coffee shop, individual user groups, etc. that exist in wireless hot spots (wireless access points, generally 1-n wireless AP or wireless routers), which allows you to have the PC with wireless  adapter anytime, anywhere easy access to Internet. Therefore, in the new semester want their own computer “cable network + wireless network” taking into account student friend, use the wireless LAN network can be easy to achieve all-round access, wireless network card has a lot of students started to become standard equipment on laptops friends .

Wireless Network Adapter Card Categories:

Currently on the market based on usage and demand for wireless cards into PCMCIA wireless network adapter, PCI wireless network card, USB wireless network card, Mini PCI wireless card, CF card and other types . PCMCIA wireless card which only applies to laptop computers, hot-swappable; PCI wireless cards for ordinary desktop use; USB interface to the wireless network card applies to both notebooks and desktop machines, hot-swappable; Mini PCI wireless card only in notebook computers, Mini PCI special interface for notebook PCs; CF card wireless network card for Pocket PC (PDA).

The speed of the wireless network adapter card, you know, IEEE802.11b products maximum data transfer rate of 11Mb / s, when the radio conditions deteriorate, the data transfer rate can be reduced to 5.5Mb / s, 2Mb / s and 1Mb / s, Supported range is in the outdoor 300 meters, in the office environment for up to 100 meters. Although the transmission speed IEEE802.11b products in general, but has been able to meet the requirements of broadband Internet access, the most important is that these products are cheap, so price-conscious student friends can also be the first of such products into the wireless network to say. It can be seen as IEEE802.11b and IEEE802.11g high-speed version, in order to achieve 54Mb / s transmission speed, 802.11g and 11b of different uses OFDM (Orthogonal Frequency Division Multiplexing) modulation method, which supports 54Mbps transmission rate. Students in the pursuit of the mainstream friends can optimize 802.11g or informal 802.11g + (108Mbps) products.

Bluetooth WiFi Wireless PCI Card

PCI (peripheral component interconnect) interface is a desktop standard interface on the motherboard, based on a 32-bit data bus operating frequency is 33MHz, per second data transfer rate of up to 132MB (32 * 33MHz / 8), PCI interface, the transmission of Performance has been able to play 802.11g + 108Mbps wireless card performance. PCI interface, a bluetooth wifi wireless pci card is that most desktop computer users to upgrade to a wireless network a better choice. You can also get more details on :http://www.espow.com/wholesale-2-in-1-bluetooth-wifi-32-bit-pci-network-card.html.

Wireless Mini Network Card WiFi Bluetooth

MiniPCI and more miniaturized MiniPCI Express wireless card is similar to notebook computers SO-DIMM memory card, compact and flexible. MiniPCI interface is a desktop based on the PCI interface for expansion out of the interface standard notebook. The wireless mini card wifi bluetooth itself does not integrated antenna, relying on preset in notebook computers in the antenna body to obtain the signal, so long as there is on a laptop MiniPCI slots and preset antenna or preset positions of the antennas will be able to easily upgrade card for wireless network card. You can also get more details on:http://www.espow.com/wholesale-54m-wireless-mini-pci-e-lan-network-card-wifi-bluetooth.html

Wireless USB network Adapter

USB (Universal Serial Bus) interface is currently the mainstream of the computer interface, both in desktop and notebook computers it as standard. USB Wireless LAN hot-swappable, making the connection and data transmission is like a mobile device, you can pull between multiple computers to pulling out, is very convenient to use. For the same time, with more than one desktop or notebook computer users to purchase several pieces of USB interface, as long as the wireless usb network adapter can be based on usage required to meet the needs of more than this computer. You can also get more details on:http://www.espow.com/wholesale-wifi-and-bluetooth-usb-adapter-802-11g-wireless-internet.html

Wireless PCMCIA/PC Network Card

PC Card (PCMCIA) is a kind of notebook-use interface, PCMCIA with Type I, Type II, Type III are three different types of products, its length and width are 85.6 * 54mm, but differ in thickness, which generally compatible with the former, the contrary is not always the case.Not like early 16-bit PC card is, the current wireless PCMCIA LAN cards are used in 32-bit PCMCIA, also known as CardBus. CardBus capable of 32-bit data transmission and 33MHz operation, its backward-compatible 16-bit PC cards, PC cards can be bus-independent so that independent of the main CPU, and the direct exchange of data between the computer’s memory, so that CPU can handle other tasks . CardBus wireless card close to the maximum throughput of 90Mbps, has been able to basically meet the demand for 108Mbps wireless card. For there is no built-in network card or wireless network card for notebook computer users, PCMCIA interface, the wireless network card is that they easily upgrade to a wireless network a good choice.

At last?hope that what I’ve said could be of some help to you.

Sophie Milch asked:


Directional Antennas also acknowledged as beam antennas can assist in focusing the energy in a particular direction which in return can help in trouncing fading and multipath, but multipath on its own diminishes the focusing power of a directional antenna. Directional antennas which are used indoors normally have a subordinate gain; with the result they contain lower front-to-back and front-to-side lobe ratios. All this results in inferior capability to discard or reduce the meddling signals received from directions outside the primary lobe area.



Most of the Directional Antennas functions occur by concentrating the energy of the antenna signal into an exaggerated unidirectional beam. In a majority of line-of-sight applications the directional antenna permits the MPX HD multipoint extender receiver to be located up to 1000 feet from the transmitter. For extensive and standard wavelength frequencies, tower arrays are utilized in most cases as directional antennas. Some of the powerful directional antennas which use 15.8dB gain, like DB8 are meant for people who are at great distances from transmitters. The bow tie design of this directional antenna utilizes triangular elements instead of rods in an effort to increase its bandwidth allowing it to cover the complete UHF band.

Some of the different directional antenna models includes HGA51G-DIR30 Directional Antenna, R&S HE300 Active Directional Antenna, Avayon DB8 Multi-Directional Antenna, TR-24H-90-17, TR-24H-120-16, Astron 5.8 GHz 8 dBi Omni Directional Antenna model VG5808 etc. Some of the manufacturers of directional antennas include Antennas Direct, CP Technologies, Bountiful WiFi, Inc, D-Link Systems, Inc, Cisco Systems, Inc, Hawking Technologies, Inc etc.

There is no denying the fact that directional antennas play a vital role for certain indoor applications, but a mainstream of indoor installations is being utilized by omnidirectional antennas. In the end it can be said that the correct installation of a directional or omnidirectional antenna could be carried with a proper site survey.

This DB8 is the ideal antenna for employing in places that can draw extensive range signals from diverse directions and tender a striking substitute to exercising a Directional Antennas accumulated on a rotator.

jackdrogba asked:


The speed of the wireless network card, you know, IEEE802.11b products maximum data transfer rate of 11Mb / s, when the radio conditions deteriorate, the data transfer rate can be reduced to 5.5Mb / s, 2Mb / s and 1Mb / s, Supported range is in the outdoor 300 meters, in the office environment for up to 100 meters. Although the transmission speed IEEE802.11b products in general, but has been able to meet the requirements of broadband Internet access, the most important is that these products are cheap, so price-conscious student friends can also be the first of such products into the wireless network to say. It can be seen as IEEE802.11b and IEEE802.11g high-speed version, in order to achieve 54Mb / s transmission speed, 802.11g and 11b of different uses OFDM (Orthogonal Frequency Division Multiplexing) modulation method, which supports 54Mbps transmission rate. Students in the pursuit of the mainstream friends can optimize 802.11g or informal 802.11g + (108Mbps) products.

MiniPCI and more miniaturized MiniPCI Express wireless card is similar to notebook computers SO-DIMM memory card, compact and flexible. MiniPCI interface is a desktop based on the PCI interface for expansion out of the interface standard notebook. The wireless mini card with wifi+bluetooth itself does not integrated antenna, relying on preset in notebook computers in the antenna body to obtain the signal, so long as there is on a laptop MiniPCI slots and preset antenna or preset positions of the antennas will be able to easily upgrade card for wireless network card. Now  you can get it on :http://www.espow.com/wholesale-54m-wireless-mini-pci-e-lan-network-card-wifi-bluetooth.html.

Description:

RF module sensitivity : -85dbm at 0.1% Bit Error Rate (BER) Security : encrypted link, authentication Bluetooth profiles support includes: Suppor VOIP WIFI Function 2.4GHz ISM band, unlicensed operation IEEE 802.11B/G standard compliant Support of 64/128-bit WEP encryption and WPA2 Operating Frequency / Channel: 2.4-2.47GHz Emission type : Direct Sequence Spread Spectrum (DSSS) Technology RF Output Power: 802.11g 54M OFDM@25`C, 14dBm Data Rate?°802.11b: 1, 2, 5.5, 11Mbps802.11g: 6, 9, 12, 18, 24, 36, 48, 54Mbp Range: Indoors: Up to 328 feet (100 meters)