The following article is excerpted from various sources and simplified to make it more easy to understand for new players or those interested in the Wireless Radio.

In terms of mathematics, units used a lot is a logarithmic unit. Logarithmic unit is very easy calculation. Well, his way of calculation you can see in the illustrations or brief examples below.

dB (Decibel)

Is a unit of difference (or ratio) between the strength of the signal transmit power. Penamaannya also to the memory of Alexander Graham Bell (hence the letter "B" is uppercase). The unit is used to show the effects of a device to the power or the transmit power of a signal.

For example:


A cable has a loss (attenuation or damping) 6dB (yes its a big loss: <) or an amplifier has a gain (reinforcement) 15 dB. Use of this unit is very useful because Strengthening (Gain) or weakening (Loss) can be calculated simply by the addition or subtraction.

dBm (dB milliWatt)

Is a unit of signal strength or transmit power (or strengths Signal Power Level). 0 dbm is defined as 1 mW (milliWatt) loads the transmit power, for example, could be from an antenna or radio. Small emittance is a negative number (eg -90 dBm).

For example: Typically the radio with WLAN 802.11b standard has a strength of 15 dbm transmit power (32 mW). This radio also has other specifications such as the RX sensitivity of -90 dbm (which is the minimum transmit power to obtain throughput of 54 Mbps)

Calculation formula from mW to dBm is as follows:

mW = 10dBm/10

milliwatt (mW) is one per thousand watt (W), or 1000 milliWatts = 1 watt. Standard International Units are watts of power (power). 1 watt = 1 joule of energy per second.

MW = 10 dBm 10:00
MW = 35 dBm 15:44
MW = 65 dBm 18:13
20:00 dBm = 100 mW
150 mW = 21.76 dBm
23:01 dBm = 200 mW
300 mW = 24.77 dBm
350 mW = 25.44 dBm
400 mW = 26.2 dBm
500 mW = 26.99 dBm
600 mW = 27.78 dBm


dBi (dB isotropic)

Strengthening of an antenna to a standard antenna imaginari (isotropic antenna). Because it is a imaginari, hence the standard antenna is only there in theory and used for measurement. Strengthening (Gain) from the antennas (above 1 GHz) dBi typically use unit. A 24 dBi Grid Antenna has a strengthening of (gain) equal to 24 dBi of antenna standards imaginari 0 dBi (isotropic antenna)

Before you buy antennas from the vendor, ask first how much amplified in units of dBi. This unit is a unit of international standards. 24 dBi Grid Antenna means though different brands have the same reinforcement is 24 dBi. Brand has no effect when the second antenna has a reinforcement (Gain) and with the same radiation pattern (radiation pattern) the same.

About Pattern Radiation (Radiation Pattern) we will discuss in another article. Radiation Pattern of an Antenna also helps transmit power or the range and can also help reduce interference in the practice in the field. (Tokowifi.com)

READ MORE - The term general term Radio Wireless (dB, dBm, dBi, ...)

What is TCP / IP?

TCP / IP protocol type is one who allows the collection of computers to communicate and exchange data within a network (the network). Who represents the set of rules allows computers to connect to each other, usually a form / time / line / error checking for data transmission.

What makes TCP / IP to be important?

Because TCP / IP is the protocol who have applied to almost all the hardware and operating systems. There is not another piece of a series of protocols available padasemua following systems:
a. Novel Netware.
b. IBM mainframe.
c. Digital VMS system.
d. Microsoft Windows NT Server
e. UNIX workstations, Linux, FreeBSD
f. DOS personal computer.

How early presence of TCP / IP?

The concept of TCP / IP originated from the needs of DoD (Department of Defense), the U.S. will be a communication between a variety of computers who have been there. DoD computers are often connected between one organization should researchers dg organizations other researchers, and must stay in touch so that the country's defense continues to run during the disaster, like a nuclear explosion. Therefore in 1969 began the study of a series of TCP / IP. Among the objectives of this study are as follows:

1. The creation of common protocols, DoD who need a protocol be established for all networks.
2. Improving the efficiency of data communications.
3. Technology can be combined with WAN (Wide Area Network) that has been there.
4. Easily configured.

DoD 1968 ARPAnet (Advanced Reseach Project Agency) to start the study who later became the forerunner to packet switching. Packet switching is who enables communication between network layer (discussed later) where the data are executed and distributed through the network in the form of small units I would call a packet * . Each packet is carrying the address information of each who handled exclusively by the network and does not depend on other packages. Who developed this network, who use the ARPAnet as the backbone, became famous as the Internet.

Protocols TCP / IP was developed further in early 1980 and became the standard protocols for the ARPAnet in 1983. These protocols have increased in popularity in the user community when the TCP / IP are incorporated into version 2.4 of the BSD (Berkeley Standard Distribution) UNIX. This version is widely used in research and educational institution and used as the basis of some commercial application of UNIX, including Sun's SunOS and Ultrix from Digital. Because BSD UNIX to establish the relationship between the TCP / IP and the UNIX operating system, many UNIX implementations today combine TCP / IP. unit where much of the information network to communicate. Each packet contains the identity (header) sending and receiving stations, error-control information, request a service in the network layer, information on how to handle the request and any important data that must be transferred.

What services are given by the TCP / IP

Here is a service "Traditional" vicarious TCP / IP:

* Shipping files (file transfer). File Transfer Protocol (FTP) allows computer users to the other one can send or receive files to a computer network. Because the data security problem, it often requires FTP username (username) and password, although many are also accessible via FTP anonymous who, Lias not berpassword. (See RFC 959 for FTP specification)
* Remote login. Network Terminal Protocol (Telnet) allows computer users can do to log in to a computer within a network. So this means that users use the computer as an extension of the computer network. (See RFC 854 and 855 for further telnet specification)
* Computer mail. Used to implement an electronic mail system.
* Network File System (NFS). Service access remote files who allow clients to access files on remote network computers even though the files are stored locally. (See RFC 1001 and 1002 for more information)
* Remote execution. Enables computer users to run a program in a different computer. Typically useful if users who use computers is limited, whereas it requires a lot of sources who in a computer system. There are several types of remote execution, some form of basic commands, that is who can run in the same computer system and some that use "remote procedure call system", who allows the program to call the subroutine that will be run on a different computer system . (As there are examples in the Berkeley UNIX command "rsh" and "rexec")
* Name servers. Who addresses the database name used on the Internet (see RFC 822 and 823 regarding the use of illuminative purposeful name server protocol to determine the host name on the internet.)


RFC (Request For Comments) is the standard who used the internet, although there is also content for discussion or who is bollocks. Published by the IAB (Internet Activities Board) who is an independent committee of researchers and professionals who understand the technical, condition and evolution of the Internet system. A letter RFC who follow the numbers indicate the status of RFCs:

S: standard, the official standard for the internet
DS: The draft standard, the protocol final stages before it is approved as a standard
PS: Proposed Standard, a standard protocol for future consideration
I: Informational, contains discussion materials allied information
E: Experimental, experimental protocols in the stage but not on standards track.
H: Historic, protocols who have replaced or are no longer considered for standardization.

Source: ipoelnet.blogspot.com

READ MORE - Definition and History of TCP / IP

As we saw in this moment, the Internet has grown and grown to reach several million units of computers that are connected in various parts of the world. From day to day information is also contained in the Internet network is more complete, accurate, and important. . Information has become such a valuable asset that needs to get a more specific treatment. Beside that, the progress made in developing a computer operating system itself and utulitasnya had so far where the level of performance, reliability and flexibility of software is becoming the main criteria in the process of software development. With more and more important and valuable information and supported by the progress of software development, certainly attract the breaker (hackers) and intruder (intruder) to continue experimenting to find and use any existing weaknesses of the system configuration information that has been established

Departing from the above facts, there is a concept which is more often referred to as Network Security. Initially, this concept explains more about security (security) of a computer network system that connects to the Internet against threats and harassment directed toward the system. Coverage of these concepts is becoming increasingly widespread, so at this time not only talking about computer network security problems alone, but rather lead to security problems in the global information network system. Several countries in Europe and America have made even one of Network Security becomes a central point of attention of the military parties respectively.

Actually, this network security problem arises from the local computer network connectivity we have with the wide-area network (like internet). So, during our local network computer is not connected to the wide-area network, network security problem is not so important. But this does not mean giving the sense that joining the wide-area network is a matter of 'scary' and full of danger. Network Security is only describe the possibilities that will arise from our local computer network connectivity with a wide-area network.

In general, there are 3 (three) of keywords in the concept of Network Security, namely:

* The risk / hazard rate,
* Threat, and
* System fragility (vulnerability)

READ MORE - Network security: what and how

The different types of wireless antenna connector that often we use in the manufacture or pengiplementasian an antenna.
Here's a picture and a little explanation of some types of connectors that we often use:

1. N Connector.

N-Female usually found on an antenna, spliter, booster, etc.. While N-Male Pigtail usually find in a (jumper cables) to connect to a wireless radio device.

N Connector

2. RP-SMA Connector.
RP-SMA Female usually find in a wireless radio devices in general and the agencies attached to the back row with a radio LAN or WAN port that serves as a liaison between the antenna with a wireless radio device. While the RP-SMA Male usually found on the rubber duck omni antenna (antenna wireless radio congenital) and on a Pigtail cables (jumper cables).

RP-SMA Connector

3. RP-TNC Connector.

RP-TNC to function basically the same as the N-Connector. RP-TNC Female usually found on the wireless radio devices, such as brands and specific types senao, linksys, etc..

RP-TNC Connector

4. MC Connector.

This connector is usually used / found on a laptop PCMCIA WLAN devices (in the form of a paste board beside the body of the laptop). Now for those who have this wireless adapter and want to add an external antenna, please replace konektro at Pigtail RP-SMA connector MC Male antenna with this. Only MC Connector is rather difficult in the encounter in the market.

MC Connector

Actually there are many more connectors that are often used on 2.4 GHz wireless radio devices
Contribute a better translation

READ MORE - Wireless Antenna Connector

We will discuss about the market share of wireless LAN, a description of past, present and future of wireless LAN, wireless LAN and the introduction of government standards. Then we will discuss some applications for wireless LANs. According to the experience of the story and evolution of wireless LAN technology is an important part of the basic principles of wireless LAN. An understanding of where wireless LAN and its application and the organization come to help the development of technology that allows you to apply a better wireless LAN into your organization or client needs.
Wireless LAN Market Share
Wireless LAN market share seems to grow as well as fashion in most network industries, starting with the early adoption of any technology that has been available. Marketing has moved into rapid growth, where the popular standard provides a catalyst. Large difference between the overall network marketing and marketing of wireless LAN can be increased. wireless LAN, providing flexibility in implementation and no wonder they moved quickly into other market sectors.

History of Wireless LAN
The spread of wireless networks, like many technologies, such as hereditary under the auspices of the military. The military needs a convenience, easy to implement, and data exchange security method in an environment of war.
As costs decline and quality of wireless technologies increases, it becomes cost savings for companies that can incorporate the wireless into their networks. Wireless technology offers a cheap way to campus to connect buildings to each other without fiber or copper cabling.

The standardization of wireless LAN
Since wireless LAN uses radio frequencies to send, the wireless LAN is governed by the same type of law and used to regulate things like AM / FM radio. Federal Communications Commission (FCC) regulates the use of wireless LAN equipment. In the wireless LAN market today, receive some operational standards and requirements in the United States are created and maintained by the Institute of Electrical Electronic Engineers (IEEE).
Some wireless LAN Standard:

IEEE 802.11 - the original wireless LAN standard set of data transfer rate of the slowest in the transmission of light-based technologies and RF.
IEEE 802.11b - describe about some of the faster data transfer and more limited in scope transmission technology.
IEEE 802.11a - image of sending data faster than (but less in accordance with), IEEE 802.11b, and use the 5 GHz UNII frequency bands.
IEEE 802.11g - the most recent terms, based on the 802.11 standard that describes the same with the faster data transfer such as IEEE 802.11a, 802.11b and in accordance with which allows for cheaper.
IEEE 802.11n-2009 is an Amendment to the IEEE 802.11-2007 wireless networking standard to improve network throughput over the previous two standards - 802.11a and 802.11g - with a significant Increase in the maximum raw data rate from 54 Mbit / s to 600 Mbit / s with the use of four spatial streams at a channel width of 40 MHz.

Since 2007, the Wi-Fi Alliance has been certifying interoperability of "draft-N" products based on what was of the IEEE 802.11n draft 2.0 specification. [3] The Alliance has upgraded its suite of compatibility tests for Some enhancements finalized after the draft 2.0 . Furthermore, it has affirmed That's all certified draft-n products remain compatible with the products conforming to the final standards.

Source: ipoelnet.blogspot.com

READ MORE - Introduction to Wireless LANs

Many people assume wrong in seeing kilobits with kilobytes per second. So often, people assume that the speed they are not getting maximum results.

When you play music or video clips via the internet, players generally displays the data rate in kilobits per second (Kbps). But in the internet browser and other software transfer file (see picture below) is always displayed in units of kilobytes per second (KB / Sec or KBps), which is it different from kilobits per second (Kbps).

This causes much confusion that often occurs in layman internet customers. Customers often assume that their speed can not match those promised by the service provider.
In the world of computers one byte equals 8 bits, please refer to the list. This means that one megabyte equals 8 megabits. Then, if your browser displays the transfer rate of 194 KB / Sec (see picture above), it means the same as you to donwload on the speed of 194 x 8 kilobits per second (Kbps), or a total of 1552 Kbps.

In other words, if your customer International Dedicated 64 Kbps transfer rate will be displayed approximately 8 KB / Sec or KBps. This value is still dependent on some factors which affect speed.

READ MORE - What is the kilobits per second?

The reason why every email you send is always up to their destination because due to "tag", which contains information about the destination. Like a bag at the airport. However, "tags" (often known as "headers" in the computer world) there are values that must be charged on the bandwidth for any data sent over TCP (Transmission Control Protocol) over the Internet simultaneously. "Tag" it will burden your bandwidth by 13% (thirteen percent).


A speed measuring site on the internet does not show the actual numbers. Because many factors influence the speed test at each site. This can be caused by:

1. Differences path (routing) is different between the backbone of one another.
2. Ability of the site provider's server receives the data.
3. Owned provider of large bandwidth speed test site itself.
4. Specification of computers used when doing the speed test.
5. In other words these sites is just an illustration that can be estimated only temporary.

SPEED Enemies

Enemy 1: Badly configured PCs
The single most common cause of poor performance is a Computer That Is in poor shape for broadband. The usual problems are:

* Insufficient memory (128MB is really the lower limit now for any computer);
* Underpowered processor (vintage computers from the early 90s with a central processing unit slower than 400MHz);
* An aging and unstable operating system, accumulation of shareware, particularly spyware etc;
* Over-clocked motherboards cause unusual problems.

Enemy 2: Packet losses
The Internet is a resilient network originally built to withstand a nuclear war. One reason for this strength is TCP, the network protocol That makes sure your data gets from one point of the Net to another.

TCP is Designed around the Assumption That Some parts of an e-mail message, for example May not get through the Net.

Thus, an e-mail message to be transferred gets broken down into "packets". For example, five packets will of attempt to take the fastest route to reach the destination, and Pls do they want, the five packets will of "combine" to form the original e-mail message.

For the sake of an example, let's imagine you are downloading data from www.microsoft.com, and one of Those many packets streaming down to you disappears en-route.

Maybe a random failure or outage knocks a network router for a microsecond, and the packet is dropped. At your end, your computer notices the missing packet in the stream of sequence numbers, and so does not acknowledge its reception.

The sender notices the lack of acknowledgment, and must re-transmit the lost data. The retransmission procedure adds to the amount of data flowing over the connection, slowing down the entire transfer.

There are many TCP copes with Airways That That networks are down. But in the end, consistent packet loss along a long internet link means the Internet traffic is often slower than it Should be, even though it May be one packet in ten or twenty That is being dropped.

If the there is continuous packet loss Between you, and your favorite sites, then Web pages or files Transfers, Which follow the TCP protocol, are going to slow down to a crawl.

If you see extremely slow performance from a particular website, then you can do a ping test, Which shows how many packets are lost along the way.The instructions are as follow:

* Go to a MS-DOS prompt, and type ping-t www.download.com (or any website you want to test with)
* Watch the sequence numbers printed. Leave it running for a short time, say 30 seconds, then press control-c.
* If you see 5% or more packet loss, then TCP performance is going to be poor over this link.
* If no packets get through at all, May you have found a server That does not respond to ping packets (Some servers do this as a security measure).
* In That Case, use the command tracert (traceroute), to identity the server That is one hop from the target server, and try pinging That instead.

To do a traceroute, the instructions are as follow: -

* Open a MS-DOS window (command prompt) and use tracert, to work out at what point the congestion May be.
* For example, tracert www.download.com. Trace route shows May Nowhere in the chain Between you and your destination the problem starts, and its nature.

Enemy 3: Many servers Can not currently offer high speeds to you
Mnet though strives to offer the fastest connectivity to the rest of the world, Sometimes the weakest, or slowest, the link is the one That your website uses to connect to the Net.

Here Are Some results of a speed test connected to Trust websites reasonably well, at 12am in the morning (off peak):

In this example, Microsoft and myisp.com would not Provide the "broadband experience" to any user they want WHO thought Had speeds of 768kbps or more.

Many servers offer speeds far slower than even this, Because They are busy, and you are sharing on their bandwidth with dozens of other people.
Servers

File

Speed
1.6mb ftp.netscape.com 310k/sec
2.0mb ftp.aol.com 280k/sec
5.0mb ftp.microsoft.com 67k/sec
5.0mb ftp.myisp.com 66k/sec

All websites have pipes connecting to the Internet on their web servers. To Ensure That all users access to WHO on their sites do not get Rejected, the bandwidth of the Internet on their pipes are sliced and divided equally Among all users trying to access on their site at any one time.

So if the number of users is low, your will of some higher speeds, but if the number of users is high, much slower speeds Can be Expected.

For Indonesia's Internet users, 12am Indonesia time Is peak hour for Internet traffic in the United States. May this mean to people surfing slowdowns to U.S. websites, Because they want have to Compete for bandwidth with the rest of the American users.

Source: ipoelnet.blogspot.com

READ MORE - How fast a pace?

1. What is the speed provided by the source or sources of the Internet in this regard is the Internet Provider, or ISP.
Internet speed is usually called the bandwidth and is measured in bytes per second (bps), or bits per second (bps). The difference is 1Byte = 8bit. REMEMBER usually written B bytes while bits written b.

2. Media liaison between the user and the ISP.
media capacity should be greater than the capacity provided by the ISP source. Type of media used also affects the quality of the Internet that is accessed primarily to the level of stability.
For media cable quality and stability are the best, while for non-cable media such as wireless or anything shaped like a wi-fi or 3G and 3.5G networks is still dependent on the quality of the signal received by the modem or the Radio Frequency (RF) used .
3. Significant factor is the behavior of users in accessing the internet. When you access a website (browsing) is in fact what happens is you are doing activities such thing as download only difference with the download of a file is that you do not know how big a file that you downloaded. Not all websites have the same file, depending on the content or the content of the website. Usually a website with a lot of picture content, streaming video or online game has a fairly large file size so that was much slower compared to if we are accessing websites that contain only text files only. The greater the content of the website slower to access our website. Based on the following formula: Access time is the amount of files to be downloaded or accessed SHARED speed internet (Bandwidth).
In addition is the use of applications (software) to speed up downloading files can cause activity such as browsing becomes slow.

4. The fourth factor is the location where access to websites that we wish to save the file or the server that served him. Examples of international websites such as yahoo american server must exist in America.
It is not a problem if the ISP you use to have the same bandwidth capacity available between the local websites and to the international website but if not, surely there must be differences in access time between local websites and international websites.

5. The number of Internet users within a local area network or LAN.
Number of users also influence the speed of Internet access.
This makes sense because the more users the more files are downloaded (see factor 3) while not increasing the capacity of the internet alias fixed. And also the behavior of each user also varies.

Source: ipoelnet.blogspot.com

READ MORE - Factors that affect speed internet access