Balance vs Unbalance

For my final year undergraduate project i am designing an Antenna for Radar applications and following is a great article to understand the concept of the Balance transmission line and the Unbalanced transmission line.

http://www.comportco.com/~w5alt/antennas/notes/ant-notes.php?pg=6

Summary:

Balanced transmission line has parallel conductors which carries current which are equal in magnitude but opposite in direction. Which makes the overall electromagnetic fields the conductors induce
approximately cancel out. So the transmission lines which are balanced does not radiate any waves which makes them not a part of the antenna but a medium which assist in transferring the power back and forth of the antenna.

In contrast to the Balanced transmission line the unbalanced transmission line has parallel conductors which contains current which are not equal in magnitude. It makes the net induced electromagnetic flux non-zero making the transmission line a part of the antenna and it will radiate a portion of the power which is transmitted by the transmitter. Therefore the efficiency of the antenna will be less.

A coaxial cable's outer shield is typically connected to the ground, and if it is a solid ground connection then the voltage at the outer conductor will always be zero. That makes the center conductor carrying the net differential voltages which makes it an unbalanced transmission line.

To connect an unbalanced transmission line to a balanced system we need a component which is known as the balun. What balun does is that it converts an unbalanced circuit into a balanced circuit. Sometimes the balun is designed such a way that it acts as an impedance transformer.

Thank you.

HP-DV6-3122tx vga issues

These days I am facing a new issue in my laptop. That is obviously an issue related with my VGA cards. The issue is as follows,

When i switch on the laptop it boots up up until the place where the windows windows logo appear. After that, in a while, the screen goes blank. The most messed up part is that still i can hear the windows log on sounds and all. When i swipe my finger on the fingertip reader i can here the windows playing the sound which comes when we log into the user account. That means even without the VGA the laptop is working.

So by default i logged into windows using the safe mode. It worked perfectly. After i logged in i uninstalled both the VGA cards and restarted the machine to see what will happen. Then of course everything worked perfectly and windows was able to detect and install the VGA plug and play drivers.

Nevertheless, when i switch off the pc and restart it sometimes the same problem occurs. I suspect that it is something about the VGA drivers. May be my drivers are not compatible with the Windows 7 SP 1. 

Who knows? 

If i found any fix i will post it here. 

Thank you.

Messing with K300i

This is something I recently did with my Sony Ericsson K300i phone. Actually it was not working so i really wanted to dissemble it and see what is wrong in it. Basically i did not have any idea on how to like repair phones. Same as any ordinary person what i did was google about it. The problem with my phone was that it cannot be charged. That is even with the charger connected it cannot be used. Apparently the problem was pretty general and there were posts on soldering few jumper wires to by pass some circuitry in the phone. Which i found a bit challenging given that my soldering iron is a cheap one and it is obviously not meant to stand up to SMD soldering. :D

Nevertheless i dissembled the phone using my newly purchased tool kit which is very cheap but has around 38 different tools <GOD BLESS CHINA!!!>. :D Dissembling the phone was pretty easy, i just removed few screws and pulled the cover away. There was a good post on K300i dissembly,

http://www.formymobile.co.uk/k300lcd.htm

After dissembling the phone i connected the charger and moved the female charger adapter connected to the phone a little bit away from the phone and it started working :D. So i used a small piece of rubber to fix the adapter in that position and assembled the phone. Now it's working again.

The problem with my phone was that since it is old and the charger adapters have been used so many times, the contacts which connects the charger to the phone were slightly disoriented. By placing the piece of rubber i could perfectly make the contacts and give life back to circuitry.

This might be useful to you if you have a similar problem.

Thank you.

OpenCV 2.4.3 with Visual Studio 2012

OpenCV is a well known library that allows programmers to easily do Image Processing. Following configurations works for 32-bit Visual Studio Version. It may work for 64-bit too. But I don't have a 64-bit version of Visual Studio. :)

I don't know much about what each process does. I have gone through several web sites and summarized the correct version,

1. Download OpenCV 2.4.3
2. Then extract it to any path you want. 
• Let the path be C:\OpenCV
3. Add following two environment variables under 'PATH'.
• User variables: ;C:\OpenCV\opencv\build\x86\vc10\bin
• System variables: ;C:\OpenCV\opencv\build\x86\vc10\bin
4. Open Microsoft Visual Studio 2012.
5. Start a new win32 console program.
6. View >> Other Windows >> Property Manager.
   
   
7. Double click on the 'Debug | win32'.
8. Common Properties >> C/C++ >> General
   
   
9. Add the following under the additional include directories,
• C:\OpenCV\opencv\build\include;
10. Common Properties >> Linker >> General
    
    
11. Add the following under Additional Library Directories,
• C:\OpenCV\opencv\build\x86\vc10\lib;
12. Common Properties >> Linker  >> Input
    
    
13. Add the following under Additional Dependencies,
• opencv_core243d.lib;
• opencv_imgproc243d.lib;
• opencv_highgui243d.lib;
• opencv_ml243d.lib;
• opencv_video243d.lib;
• opencv_features2d243d.lib;
• opencv_calib3d243d.lib;
• opencv_objdetect243d.lib;
• opencv_contrib243d.lib;
• opencv_legacy243d.lib;
• opencv_flann243d.lib;
14. Now click ok.
15. Next I have downloaded two '.dll's which were missing,
    http://www.mediafire.com/?115pz9e0xpa0059
    Then I extracted them into,
    C:\OpenCV\opencv\build\x86\vc10\bin
16. Finally run the following sample program to make sure that your configuration is successful.

#include "stdafx.h"
#include "opencv2/highgui/highgui.hpp"
/**
* @function main
*/
int main( int argc, const char** argv )
{
CvCapture* capture;
IplImage* frame = 0;
while (true)
{
//Read the video stream
capture = cvCaptureFromCAM(1);
frame = cvQueryFrame( capture );
// create a window to display detected faces
cvNamedWindow("Sample Program", CV_WINDOW_AUTOSIZE);
// display face detections
cvShowImage("Sample Program", frame);
int c = cvWaitKey(10);
if( (char)c == 27 ) { exit(0); }
}
// clean up and release resources
cvReleaseImage(&frame);
return 0;
}

Enjoy!!!

Reference:

1. http://docs.opencv.org/opencv_tutorials.pdf
2. http://karanjthakkar.wordpress.com/2012/11/21/usin-opencv-2-4-2-with-visual-studio-2012-on-windows-7-64-bit/

Changing the BOOTMGR location

BOOTMGR is the fie which boots windows. Normally it is installed to your first hard-drive. So there can be instances where you install your new Windows into newly bought hard-disk, but without your old hard disk you can’t boot your computer. To check whether this is your case, just go to BIOS and disable the hard you think you don’t have windows installed on and try to boot. If it gets booted then no problem, else you can do this easy fix.

Actually this is very easy fix since a software will take care of all the trouble. You just need to download EasyBCD which is luckily a freeware but a very valuable software. After installing it you can do the following,

1. Click on BCD Backup Repair         
2. Select Change Location
3. Select the new partition.
4. Click ok.

After this simple process, you are good to go!!!

Thank you.

Ansoft HFSS quick guide to dipole simulation.

If you know HFSS, then this will be understandable. If not i recon that you should go through a detailed tutorial. This is just a side note so that one will be able to follow the steps easily. 

1. Open HFSS.
2. Start a New Project
3. Insert HFSS
4. Set solution type
5. Set units
6. Set design properties (variables)
7. Draw one pole of the dipole.
8. Set the material.
9. Duplicate it along the x-axis
10. Draw a rectangle in YZ-plane
11. Make it the lumped port
12. Draw the E-field vector.
13. Insert the radiation boundary. (Select faces and apply the boundary)
14. Make the material to vacuum.
15. Add solution setup.
16. Define frequencies to feed
17. Define the frequency sweep.
18. Validate & Analyse.
19. For far field make sure to insert Infinite Sphere for Radiation.

Thank you.

HP-Pavilion dv6 3122tx errors

Ok this all started with a simple update. I usually use ATI-hotfixes for my driver updates since hp hardly release compatible driver updates to switchable graphics enabled laptops. But this time surprisingly my catalyst controller itself asked me whether I would like to install the new catalyst controller 12.10 or something. I thought what the hell, if it is the new driver and if my catalyst controller is suggesting it I should not worry. So I went straight ahead and updated the driver. Everything has gone smoothly, until I switch on the laptop next day.

I switched on the laptop and I couldn't click on any of my task bar buttons and my laptop charger is also not detected. And there were random flickering in my display. I got worried and then I restored windows. The restore also crashed for I don’t know what reason. It gave me lots of software issues but the hardware was ok. So I spent around 3~4 hours and repaired the software.But now the messed up part is that sometimes my display driver (Ati 5650) does not get detected in the device manager. But sometimes it does.

So currently I am only using the Intel drivers and using the Intel hd driver in the laptop, but the laptop is expensive only because of its video driver and without it it’s not worth the amount. So these days I’m trying to fix that error.

Today I removed Catalyst Controller and the ATI drivers from my laptop. Now hoping to download them directly from the hp website and see how it goes. HP-pavilion dv6 is a good laptop but with switchable graphics it sucks. :D

Thank you.