LINK PLANNING

A basic communication system consists of two radios , each with it associated antenna,the two being seperated by the path to be covered.In order for the two to be communicating,the radios require a certain minimum signal to be collected and presented to their input socket.Link budget calculation is the process of determing the feasibility of the link.Weather or not signals can be passed betwween the radios depends on the quality of the equipment being used and on the diminishment of the signal due to distance ,called path loss.
Calculating the link budget.
The available power in an 802.11 system can be characterised by the following facters:

• Transmitt power:transmitt power ranges from 30mW to 200mW or more.This power is often dependent on the transmission rate and is either measured in mW or in dBm.Tx power of the given device should be specified in the literature provided by the manufacturer.
• Antenna Gain: Antennas are passive devices that create the effect of amplification by virtual of their physical shape.Thes devices have the same characteristics when transmitting ang when receiving.So a 12dBi antenna is simply a 12dBi antenna without specifying weathwe it is in transmission or reception mode.Parabolic antennas have a gain of 19-24dB,omnidirectional antennas have 5-12dBi while sectorial antennas have roughly a 12-15dBi gain.
• Minimum received signal level:This is simply the sensitivity of the receiver.The minimum RSL is always expressed as a negative dBm and is the lowest power of singal the radio can distingiush.The RSL specifications should be provided by the manufacturer of the equipment.
• Cable Losses:These are the signal energy losses that take place in cables ,connectors and other devices ,going from the radios to the antennas .These losses depend on the type of cables being used and also on their lengths.
• Path losses:Free space losses ,attenustion and scattering are effects that must be considered when dealing with path losses.Free space loss is the diminishing of signal power by geometric spreading of the wavefront.It depends only on the distance i.e the loss happens because the radiated signal energy expands as a function of the distance from the Tx.Attenuation takes place as some of the signal power is absorbed when the wave passes through solid objects such as trees,walls,windows and floors of buildings.Attenuation vary greatly depending on the structure of the object th signal is passing,and it is quite difficult to quantify.The processes that lead to attenuation include Absorption,Reflection,Diffraction and interferance. However, diffraction and interferance can be useful. Along the path , the RF energy leaves the TX and then it spreads out .Some of the RF energy reaches the antenna directly while some bounces off the ground.This is called scattering.The line of sight thet we need in order to have an optimal wireless connection from A to B is more than just a thin line.Its shape is more like that of a cigeror an an ellipse.Its width can be decribed by the concept of Fresnel zones.

To evaluate the link feasibility,one must knowthe characteristics of the equipmentbeing used and evaluate the path losses.For it to work the condition is that (Radio1 Tx power +Antenna gain-losses)>Radio2 sensitivity. This calculation is performed on both sides of the radios and the acceptable difference between the two sides should be atleast within(3-6dB).

Football-Soccor Fan Side of It.

People think that being a soccer fan is a matter of life and death,but i want to assure them that it is much more serious than that.I think that as a soccer fan,you even tend to have deeper feelings for the club that you support than the players themselves since these people -the players can easily switch clubs but we can not.They merely play for the big money they earn while we just feel part and parcel of the club.It is like one has fallen in love with that particular club.You just love how they play their football and it becomes the only club you best enjoy watching.
I remember in my third year of study at Unza during second semester's exams.I had not prepared myself adequately during the semester as a result ,i needed to to study about half of the course in a day and i was writing that exam at 09hrs the following day.But unfortunately there was a champions league game between Arsenal(the club i support) and PSV endhoven in the evening. Guess what i managed to to spare about two and a half hours for the game. I had to punish myself afterwards to try to recover the time i had lost as a result i only slept for two hours .However , i managed to clear the course.
Also early this year there was an English FA cup match between Chelsea and Tottenhan hot spurs.Chelsea won 2-1 and while the Chelsea players were celebrating,a spurs soccer fan dashed from the crowd to attack the Chelsea ace Frank Lampard .Lampard managed to to avoid the soccer fan's swinging punch and with the help of other teammates ,they managed to wrestle him down and had him handed over to the security.This person was just not happy with the loss of his team and that was the only way he could react.
These are some of the crazy things soccer fans are capable of doing which show how serious it is to be one of them.

Wireless Networking(Setting up an AP-Client configuration)

Wireless Fidelity (Wi-Fi) is becoming one of the most powerful tools of networking in the communication world.It uses waves which are in the microwave range of the elecctromagnetic spectrum.These are typical microwaves and as such,they get shielded by things like water,trees e.t.c or simply whatever material which gets hot in the microwave oven can interfere or disrupt the signals.There are basically four wireless modes of connecting these Wi-Fi devices.First,there is the Access Point mode ,then Client mode, the Ad-hoc mode and lastly the Passive mode.Looking at the AP-Client configuration in Macha,two wireless 'boxes' are used.Mostly these are Wireless-G Broadband access points WAP54G and the Wireless-G Broadband Routers WRT54G.These two boxes can be seen in the picture above.The front parts are coloured blue.These are the Linksys Broadband routers which can be looked at as three things in one box.That is there is the wireless access point , which lets you connect both streaming fast wireless-g(802-11g at 54mbps) and wireless-B(802-11b at 54mbps)devices to the network.There is also a built-in-4port-full-duplex 10/100 switch to connect your wired-Ethernet devices together.This means four PCs can be connected directly or one can attach more hubs and switches to create as big a network as may be required.Finally one can make the whole network share a high speed cable or DSL internet connection. To set up the AP-Client configuration,you need the two boxes and standard Cat-5 cables with Rj-45 connecters.The package come with the user guide on setup CD -ROM ON which all the instructions are properly documented.You first need to connect the broadband router ,confiure the PCs,and then configure the broadband router.You configure the PCs by giving them the appropriate IP addresses,subnets,gateway and the domain name server(DNS).To configure the routers,one has to be made the Access Point and connected to the WAN while the otherone is made the client.The AP is geteway between the WAN and the WLAN and thus it needs two ip addresses for each network.On the other side, the client is the gateway and also needs two ip addresses for each respective network.You can have one AP with several clients but it shouled be borne in mind that the more the clients the smaller the bandwidth.

CARS!

I have always had a weakness for cars ,beautiful cars,expensive cars ,luxurious cars,powerful fast moving cars.I have always dreamt of owning such a piece which bears swift mechanical engineering art and technology.However , i can assure you for me to actually think of buying one,i need to first all accomplish much more important goals i have set for myself.This is because i find these cars to have an extremely high and politicised price.For example ,think of the so many projects one can undertake using one billion kwacha.As a matter of fact you can actually come up with a garage of these other common cars or even small trucks using the same amount of money.Surprisingly enough, you will need a little more money than that to acquire a British made Aston Martin DB9 Volante which is valued at about 130 000 pounds.From the picture above,you can see that with this car (on the left) you can do very little apart from pleasure and showing off.You can't even cary with you a family of four to have pleasure together and yet it has a relatively high fuel consumption .This fuel consumption is for the purposes of fast acceleration and high top speed.The same goes for the car on the right.It is a British made Bentley GTC. Here in Zambia as well as most parts of Africa,the roads are not even good enough to accommodate such cars.With these reasons i think these cars are not yet meant for us here in Zambia because we need to do a lot to develop so that we can start showing off!

My Career-Electronics &Telecomunication Engineering

As a little boy , i always admired toys ,machines,big trucks etc and i found myself inclined more on natural sciences than on social sciences at school.I kind of get satisfaction whenever i learn something in these sciences.I also developed interest in accounting at my high school level but it was ruled out because it is not offered at UNZA and i couldn't sponsor myself to go somewhere were it is offered.Therefore,upon completing my grade 12,i knew i was getting into an engineering field but i didn't know exactly whichone. This was because i did have but not enough information about what is actually involved in these branches.In my mind i had electrical, mechanical and civil engineering. However, due to the fact that nearly everyone in our group wanted to do EEE,it was popular and i was able to acquire enough information about it as well as the others.I found out that i liked most of the things in Electrical and Electronics Engineering and also that it is marketable.In EEE, there are two sides-Electrical Machines & Power engineering and Electronics and Telecomunications engineering.I found myself belonging naturally to the ET part because of the unlimited adventure involved.TO BE UPDATED SINCE I AM A STUDENT ENGINEER!

Attachment to Linknet

Being a fourth year student at UNZA studying Electronics and Telecomunications engineering,it is a minimum requirement that i do fourteen weeks of industrial training.This actually involves bridging the gap between the theory learnt at school and what is applicable on the ground.Since The University uses a semester system,there is hardly any other time for such apart from the vacations.This means that as a student in the School of Engineering the last three years are dedicated to academic work. UNZA particuraly the School of Engineering does't look for places in companies were students can be placed for such experience.That is to say no student can blame the University for not having a minimum of fourteen weeks of industrial feel of their career.Thus, no 14 weeks of training no graduating. This becomes an issue for students because a mere application from a student does very little to persuade companies to concider you for attachment placement. However, a few companies and organisations who mean well to the students and society at large come forth through the school of engineering offering places for students to be trained . This time Linknet was one of them.It requested for six students and i was fortunetly part of them.Consequently,i wish to commend Linknet for the good gesture it has shown to UNZA. On our attachment, we were to work on a project which was to come from topics such as:the use of linksys+directional antennae for WAB,Research on wireless units and future radios,A simple solar panel project with supplies available only in Choma,To discover and document the network topology for Linknet in Macha. This was to be done within a period of one month with food and accomodation provided by Linknet.After carrying out a fisibility study i beleive, Linknet proposed that we do the last option of the listed topics.This was the minimum thing to be done because there were lots of things to learnt in and outside technical circles.

Having travelled all the way from Lusaka to Macha-an organised fast growing area off Choma district in the southern part of Zambia,i was so tired that i could hardly see much of the area. Worse still we arrived at about 8pm so the darkness wouldn't let me explore the area otherwise.On the way,our crew included Mr. Luka Ngoyi H.O.D Electrical& Electronic Engineering-UNZA,Mr. Gondwe senior technitian Electrical Engineering-UNZA, Mr.Mulenga- driver and i was among the six Electrical Engineering students from UNZA. We used a small minibus from the transport yard-UNZA which was surprisingly effective considering the 70km gravel stretch from Pemba to Macha. It took us a total of about six and a half hours to travel from Lusaka to Macha. However, the folowing morning Mr. Vanstam-Linknet Direcctor took us round and oriented us to the place.People around looked so busy their projects i.e some were erecting buidings ,carryingout researches on malaria, teaching e.t.c.Nearby there was a nurse training collage,a Hospital and The Ubuntu cumpus whose building was one of those being erected. Due to lack of a tarred road and also due the need of fast transport in such an area, there is an air strip to accomodate small planes.