When deciding to deploy a Wireless LAN (WLAN) solution within a building or facility, there are many factors to consider. The first most obvious consideration is the radio or RF coverage required within the facility, the size and design of the facility will determine the number of wireless access points required to provide that coverage. Another consideration will be selection of the appropriate wireless antennas to provide the desired coverage.

The wireless antenna is one of the most important components of any wireless access point or wireless client device, because it is the antenna that determines how the radio signals are propagated, what type of radiation pattern they produce and how much gain they produce. The radiation pattern may be isotropic, meaning that the antenna radiates the signal equally in all directions, and we often refer to these antennas as omni-directional. Depending on the siting of the antenna, we may need a radiation pattern than is not isotropic, but radiates in a pattern that maximises the radio signal in a certain direction.

Before we get into a description of different types of WiFi antenna, how much gain they produce and what type of radiation pattern they typically provide, I must stress that when deploying a wireless LAN for the first time, it is very important to have a wireless site survey conducted to determine the siting of the access points and also highlight any problem areas where specialist wireless antennas may be required.

A Wireless Antenna will normally be designed to work efficiently over a narrow band of frequencies, the wider the range of frequencies the antenna will operate over, the more “Broadband” the antenna is said to be. WiFi Antennas will operate either in the 2.4Ghz ISM band or the 5Ghz band, so the antenna must be designed to operate within those specific frequency ranges.

In most countries there will be a restriction on the amount of power a wireless antenna can transmit, and this is usually in the region of 1 Watt, with a 6dBi gain for omni-directional antennas and somewhere in the region of 23dBi for directional antennas. The reasons for the restrictions being mainly to reduce interference with other users within a particular frequency band.

Antenna gain is the measure of how much effective signal power is increased by an antenna for a given input power, and is measured in decibels (dB). Decibels are calculated on a logarithmic scale, and an example would be a 3dB increase represents a doubling of power ie. 25 milliwatt input would produce a 50 milliwatt output. EIRP or Effective Isotropic Radiated Power is determined by the Transmit Power and Antenna Gain ie 15 dBm transmit power with 6 dB gain would produce an EIRP of 21 dBm

Lets take a look at some of the antenna types available and how they typically perform:

Omni-Directional Antennas

This type of Antenna, as previously stated normally produces an isotropic radiation pattern that is often referred to as a “Doughnut” shape. It is worth bearing in mind that true isotropic antennas tend to be purely theoretical and other types of omni-directional antennas are compared to that of an isotropic design.

Vertical Omni

A vertical omi-directional antenna is usually based on a dipole design where the radiation pattern of a dipole antenna is 360 degrees in the horizontal plane, with the vertical plane varying depending on whether the dipole is vertical or not. A vertically orientated dipole antenna normally has a 75 degree radiation pattern. Dipole antennas are normally said to have a gain, on average of a little over 2Db.

Ceiling domes

These antennas are designed to be mounted on the ceiling, above false ceilings or even on walls. Because of their less obstructed view, they tend to have a higher gain of around 3Db.

Rubber Ducks

Rubber duck wireless antennas were first used with early walkie talkies as a cut down whip aerial designed at one quarter wavelength. Because of this they are termed electrically short antennas, usually having a wire type element covered with a rubber sheathing, making them flexible and robust. They are vertically mounted and have a 360 degree radiation pattern similar to that of a half-wave dipole. These are the antennas that you see on most mass produced wireless routers for the home market.

Directional Antennas

Reflecting and radiating elements are added to the standard di-pole design to concentrate the signal energy in a specific direction. Directional antennas can give a gain over the standard isotropic antenna of between around 3dB as much as 20Db.

Yagi

Yagi antennas are referred to as high gain antennas and have multiple reflector and radiating elements to give a typical gain of between 12 and 20dB. They are often used as outdoor antennas and will have a typical horizontal beamwidth of around 30 degrees and 15-25 degrees vertical beamwidth.

Dish

The most common type of dish Wireless Antenna is the parabolic dish, which uses a curved parabola shaped dish to direct the wireless radio waves to a narrow beamwidth. These type of antennas are extremely highly directive and can also have extremely high gain, as much as 40 or 50dB. One of the design factors is that the dish will be larger than the wavelength of the design radio frequency. Most often used for point to point wireless communications links. Outdoor wireless bridges will often use a Parabolic Dish Antenna.

Patch Antenna

You will often find Patch Antennas deployed in office type environments, normally attached high up on a wall, or sometimes ceiling mounted. Typical horizontal beamwidth is around 70-80 degrees, but this can extend to around 100 degrees. Construction is normally a pair of metal plates that are actually the antenna elements, which together make up the transmission line. They are normally of half-wavelength design, with typical gain being around 2dB, similar to a traditional dipole antenna.

Of course, there are many other variations of wireless antenna which have not had a mention here, but this article was designed to give the layman a simple explanation of basic Wireless Antenna types.

Following a successful Wireless Site Survey, the majority of access points in anything but the smallest office environment will normally employ dome antennas or vertical dipoles. Problem areas may be better served by Patch or Sector wireless antennas to maximise the coverage area.

David Christie is MD at NSTUK Ltd, a Technical Training and Consultancy company based in the Northeast of England. David delivers technical training in the area of Data Communications and Telecoms and also provides consultancy and Training Needs Analysis. The company runs an ecommerce website specialising in the sale of Networking hardware and consumer electronics. Website: http://www.ipexpress.co.uk

Article Source: http://EzineArticles.com/?expert=David_W_Christie
Article Source: http://EzineArticles.com/6852507

DIY wireless antenna from pot. I think this is just another coincidence that the diameter of the pot and the position match the right condition to get great signal.

diy wireless antenna

A year ago I have been actively involved in rc drifting. Since then I had learn and improved a lot on how to setting up good rc drift car. One of the setup that involving so much try and error is counter steer setup or know as CS drift. The idea of CS is to make it more realistic same as the 1:1 drift. I have my Tamiya TRF 415 MRE for this purpose, it not difficult to setup since it is a belt driven rc car, so i just need to modify the pulley setup to match the ratio that I want, The perfect ratio that i currently use is 1.7 with special damper setting (Video below).

Its been a while now, I dint really have much time to play rc anymore since i have another focuses. For those who want to start counter steer drifting you can download the setup sheet in excel format here cs-ratio. For the beginner i would advise you guys to start with 1.5 ratio and continue with 1.7 if you feel comfortable. Exceeding 1.7 would be a bad idea since you will feel frustrated controlling the car.

Training session with TRF 415MRE and Levin Bodyshell

Setup
TRF 415 MRE
CS Ratio 64%
LRP ULTIMO Brushless Type 1
Damper Piston Mod

Wireless technology has become an integral part of our daily life, ranging from wireless phones, internet connection to the way upto electricity. Though the last one is still mostly in the developmental stage. However, we are today going to have a look over into the wireless internet part which is mostly done through wireless routers.
Wireless routers are the devices which are used for converting your wired internet connection in your home or office to a wire free one. Most of you reading this article would probably have one installed in home or your office. Today we will discuss about the things that can help you to protect your routers from hackers.

Stop Broadcasting Your Routers SSID: When you connect your computer to the internet, it forms a two way connection with a pc and the internet. Now, each router has a SSID or Service Set Identifier or simply a name. When your broadcast the name over the air, and it reaches to all people, everyone becomes alert that there is an existing connection. And hence it makes the work of the hacker easy. So the first thing that you need to do is to go and disable the option inside your router admin panel.

Encrypt Your Signal: If you are not encrypting your signal, you should be cautious about it now itself. As all your communication with the web server is available over the air in your vicinity. And can be viewed by anyone passing with a minimal effort.

In general there would be normally two versions of encryptions available in your router admin panel. The old WEP connection or the newer WPA connection. Always make sure to use the later as it is much harder to crack and should be enough to fend off most of the trouble makers

Enable Router Firewall: Firewall acts as a castle to protect your computer form external attacks and acts as a bouncer for rouge programs to stop smuggling of data in and out of your computer to the network. Every modern router has an inbuilt firewall system which protects the network. It should be kept enabled all the time to deter threats.
Limit The No Of IP: If you are using you are using your router in home or office, there should be a definite no of computers that would be regularly connecting to your router. But the routers are designed to give an IP to which ever devices asks for it. So there’s no point in keeping the security hole available for other person to use. It can be easily closed from inside the router control panel.

Intrusion Detection system: The modern wireless routers now a days have an intrution detection using which you can see the devices that are connected in your network and keep track of them using the alarming system. If you do have the system, make sure to enable it, so in case someone slips in he/she can be shown the way out quickly.
Restrict Devices Based On Mac ID: Every device that connects to the internet has a Mac id associated with it. Hence this Id can be effectively used to filter the devices which are permitted to connect to your wireless router, and to leave out the rest. The Mac filtration system remains inbuilt in the router control panel and can be easily be configured by you after you have located your device, Mac ID. Even though, cloning and spoofing of Mac Id is possible, still it can keep you safe from small hackers.

Deactivate Wan Ping: Wan Ping or Wide Area network (Internet) ping, is used for diagnose purpose to find your router over the internet. When this is enabled, if someone pings your router IP address from the internet, it will respond to that ping to let that, it is alive or online. This is one of the tricks used by hackers to find its victims. This option can be disabled and hence can save your router or network from undesired attention.

Update Your Router Password: Every router has a default password to login to its admin panel. Most of us forget to change the password and hence falls victim to hacking. If the password of the router is not changed all the above setting can be nullified by the hacker and hence can be made useless. As soon as you install a new router make sure to change the default password, to a good password that can’t be easily guessed.

The iPhone 3g is the type of phone that is effective of every function of other mobile phones. It has various features that make it capable of some business and home functions of the computer. However, there are some features that you cannot access unless the phone is unlocked. Unlocked iPhone 3g uses both 2G and 3G network internet connection of GSM 850/900/1800/1900 and HSPDA 850/1900/2100 in that order as mentioned. The phone was first introduced in 2008 in the moth of June and the same year in July, it was released.

Unlock iPhone 3g Video

It is very light weighing about 133 grams. It has a sleek and slim design which is very unique with a dimension of 115.5x 62.1x 12.3 mm. it has 3.5 inches TFT capacitative touch screen that measures 320x 480 pixels. But of course unlocked iPhone 3G is multi touch and has a corning gorilla glass which protects the important parts of the phone. Its sound feature is also great. It has a vibration and propriety ringtones for types of alert. It is fitted with 3.5mm jack as well as a loudspeaker.

The phone does not come with a memory card slot due to its large storage space. It has an internal memory of 8GB with its random access memory having 128 Mega bytes. You are always guaranteed of fast transfer of data since the phone is EDGE and GPRS enabled. In addition to that, it uses HSDPA speed. It also has a Wi-Fi of 802.11b/g which has the capability of delivering a speed of up to 54mbps which is very impressive. Other data transfer features include 2.1 version of Bluetooth and 2.0 version of USB. All these when combined ensures fast transfer of data
The phone comes with an inbuilt 2.0 mega pixel camera of 1600x 1200 pixels. Unlocked iPhone 3g uses an iPhone operating system which is upgradable to iOs 4.2.1 version. It has a central processing unit which is also known as the processor of 600MHz cortex-A8. This enables you to execute programs with your phone.

The phone does not have a radio but comes with a global positioning (GPS). The GPS enables you to determine the location where you are, the time as well as velocity. The phone also comes with a lithium-ion battery which is standard and various installed applications such as twitter, Facebook, Picasa and Google maps among others

This is a guest post by:
Learn how to unlock iPhone 3g by checking details on unlocked-iphone.org.

The macbook pro has always been apples famous laptop model that packs power and speed in a portable mac. As usual ever year apple tends to upgrade its model and the macbook pro 2012 is looking all the much more impressive. The current macbook provides portability and power with great hard drive storage, upgradeable ram, decent graphics and CPU. Though it lacks in new technologies being adopted and in the graphics card upgrade department. While being a laptop and desktop replacement we hope to see apple focus on the form factor and cramming more hardware into this machine.

Macbook Pro 2012 : The Slim Factor

Reports show that we’ll see slimmer 13 and 15 inch models in production for the latest release. Along with that we’ll most likely see CPU upgrades with Intels new Ivy bridge CPU. Either adopting the macbook air form factor and or keeping its classic design with improved hardware like Ram, hard drive capacity. Display wise the screen size will most likely be the same size at 13 and 15 but possibility of a improved resolution and possible “Retina” display. This tech we’ve seen implemented into the 3.5 inch iPhone 4 and 9 inch iPad. Going up to around 13 and 15 in size wouldn’t be to difficult this means we could see resolutions up to 2880×1800. Lastly graphics wise to power it all its possible we’ll see apple move back to the NVIDIA graphic chips to power all the latest tech. Seeing as this is usually the biggest gripe with current macbook pro owners we hope to see a big upgrade in this area.

Latest OS X : Mountain Lion

Topped off with latest OS X software “Mountain Lion” the mbps will look to provide more power, more speed and efficiency in a machine thats lighter and more portable than the last. While implementing new technologies and hopefully improving or maintaing the classic battery life. Other than form factor change the design can’t deviate much from its simplistic look that the macbook line has held. Probably integrating new tech like improved thunderbolt ports, USB 3.0 possible and even look into blu-ray drives. This would make the macbook pro support all the latest technologies out there in an all powerful mac machine.

The Price Tag

Price point is yet to be determined but surely with the upgrades it’ll be around the same if apple can pull it off or slightly higher but with tons of upgrade options from SSDs, etc. The new Macbook Pro 2012 will surely be a thing to look forward to. Redefining the standards of a laptop that can also serve as powerful desktop replacement. With jobs gone who’s to say what decisions will be made on apples or tim cooks part on what will be implemented. As with the iPad 3 we saw new technology integrated that we may have not seen otherwise. Surely apple will look to hold its place in the notebook market appealing to colleges students, graphic designers , and all around power users with this latest macbook pro 2012.

Have you ever been super frustrated when your Android device downloaded a whole lot of data (videos, music or something else) not via WiFi, but via your mobile plan? If you have, welcome to the family! This stupid thing just happened to me today. But the good news is that you can actually use a pretty neat piece of software that allows you to avoid such situations. This app can be downloaded at Google Play. (duh!)    So, the app is called SPB Wireless Monitor and it’s a real lifesaver, because it offers you all the stats you might ever need in terms of your Internet data consumption. Let’s break it down more in-depth.

Application report

This portion of the interface shows you which exactly app used the internet and to what extent. So, you can always go to the section and see who’s to blame . For example, in my case the biggest internet data consumer would be DoggCatcher (a podcast app). Well, that’s because I’m an absolute podcast junkie, so I tend to watch and listen to all sorts of podcasts out there.

Traffic Report

It’s another useful feature of the app. It basically shows you when and how much data was downloaded via mobile, WiFi, and in total. So, you can easily check when you use the internet most of the time and if you need to change your behaviour in any way. For instance, you may want to set your podcast updates for the time (like in the evening) when you’re most likely at home. It’ll help you to optimize your expenses on mobile internet plans.

Alarms

You can set an alarm (just click the plus sign in the upper-right corner)  that will let you know when you’ve used your daily limit of mobile Internet. It’s really useful if you’re not on an unlimited mobile plan. It allows you to specify the traffic (or cost) that should be considered critical. You can also specify the time span you need for that (today or this month). And sure thing you can set the amount of data (in Kb, Mb, Gb or %).

Tariffs

This feature allows you to set your tariff so that the app can count your data use properly. The options of the feature include: country, operator name, tariff name, monthly pay, off-peak, data round, etc).

Export

You can export your stats info as an csv file. You can set the report’s period (today, this month, this year), type (mobile, WiFi, Apps), and kind (Traffic, Cost).

Settings

In this area, you can specify the following:

• Which day (Sunday or Monday) should be considered the first day of the week;
• Traffic measurement unit (binary or decimal);
• Screen orientation (auto, portrait, landscape);
• Main screen (this week, this month, this year);
• Statusbar notification (today, this week, this month, this year);
• Refresh frequency (from every 30 seconds up to every 1 hour).

Plus, you can also reset all your stats data in case you wanna start afresh for some reason or other.    Apart from being feature-rich, it also has a really professional design, which makes the app a genuine eye-candy. Highly recommended. Keep in mind that I got no money for saying that at all

About Author : I’m a dude from WebDesign Bureau. I can explain how to make a website or just create it for you. Plus, I’m crazy about all the things web and mobile.

The iMac has been apples all in one desktop since the 90s and continues to be upgraded in terms of speed and form factor. The 2012 iMac is a work in progress and is only updated so often , being last updated with the i3,i5, and i7 processor mid 2011. We hope to see an all new iMac come late 2012. Serving as one of apples only remaining desktop models aside from the mini and pro the iMac services users who are either new the mac family and need a desktop replacement or power users who want the flexibility of the iMacs all one interface and the power it holds.

IMac 2012 Our Hope

The new 2012 iMac hopefully will bring some key things. First a whole new design possibly even a new 30 inch model from its 27 inch counterpart. Default size possibly being upgraded to the 25-7 inch range from its 21 inch current size. Upgrades hopefully in the display to make an even better looking screen as we’ve seen apple implementing retina displays in much of their new tech. Additionally we will see the new intel Ivy bridge processor providing power for mid range users and hardcore users alike. All while maintaing its key compact all in one design. Appearance wise we hop to see some new tweaks from curves to possible border to border display. Along with more flexibility in its ports upgrading to support more thunderbolt ports and usb 3.0 and or even blu ray.

iMac 2012 will focus on providing more power and upgrading the standard of technology while slimming down the overall build and improving performance not just hardware wise but eco-wise and cooling wise as well. Possible new vent system to improve air flow and of course implementation of eco-green parts as apple is highly focused on their environmental goals.

Cutting Edge Hardware and Software

Packed with OSX Mountain Lion and new hardware coming in the 2012 year the iMac will have surely new graphics card, CPU , improved screen and even ram. Possibly a push even for SSD standards in the iMac to increase overall performance as new SSDs have been released with more capacity then before to replace your standard HDDs. This will keep apples desktop line running strong and fresh for the year to come as the iMac all in one design is a favorite for customers getting to save on physical space while maintaing power and a reliable overall macintosh. The 2012 iMac will strengthened its dominance and redefine the existing iMac design we know and love and improve on it ten fold. Fitting more in a smaller space while improving everything else that makes a mac that much better.

IMac 2012

Online collaboration is a reality and companies all over the world are starting to realize its potential to increase productivity and speed up many tasks that used to be time consuming. Without leaving their offices, employees can now communicate and work together in real time on the same projects even if they are many miles apart.
Looking for the best Web Conferencing solutions available in the market? Here are some suggestions:

1.Adobe Connect

Adobe Connect is powerful and very easy to use web conferencing solution. Participant invitation is very easy to manage and the meetings are easy to deploy with seamless integration with Outlook. One of the great functionalities of the Connect is that it allows the meeting host to have full control over the functionalities and rights that every participant has during the meeting. Like GoMeetNow, Adobe Connect can be used to deliver webinars and employee training over the internet. Adobe Connect 8 has several subscription fees but the standard is $55 per month for unlimited meetings up to 25 participants.

2.GoToMeeting

GoToMeeting is one of the most popular web conferencing tool available in the market. Deceptively easy to use, GoToMeeting has very intuitive user interface and lots of features that make this solution worthwhile. It allows for desktop and document sharing with VoIP capabilities and webcam video supporting up to six participants. It has the cost of $49 per month or $468 per year for unlimited web conferencing and online collaboration of up to 15 participants.

3.GoMeetNow

GoMeetNow is one of the best web conferencing solutions available in the market right now. It allows its users to work together on a virtual environment while talking, via VoIP, and seeing each other through the use of their webcams. The user interface is very intuitive and clean while at the same time it offers many functionalities, including full desktop and document sharing. GoMeetNow also allows the deployment of webinars, where a presenter can share his desktop making it an ideal tool for employee training. Another good thing about this solution is the price. GoMeetNow can be used by 2 participants for $12.95 per month and up to 5 participants for $15.95 per month, both with unlimited meetings. The solution is very easy to install and requires no maintenance.

4.ClickMeeting

ClickMeeting is another good solution for those looking for a web conferencing tool with online collaboration capabilities. It is very easy to use and it has several nice features which enhance online collaboration, among them a whiteboard where all participants can work together and even deploy their webcams while they do so. ClickMeeting also allows attendees to share their desktops and documents in several formats. Like other solutions, ClickMeeting is great to give webinars. The company is offering a 30 day trial and several packages at different prices for those who wish to buy it after that.

5.MegaMeeting

MegaMeeting is a nice application web and video conferencing. Although it is not always intuitive, MegaMeeting has a important feature — integrated VoIP. It is easy to install and it integrates very well with Outlook though inviting attendees and changing their rights might, at times, be tricky. It can also meet your need for hosting webinar.