Author: VU2SWX

FOSS in Engineering Colleges

Shayam has written a nice letter to his HOD on usage of free software in laboratory experiments. As a teacher, I am trying to use free software in my own college. The problems mentioned in his letter is existing in all most all colleges in Kerala.
The root cause for this is in the syllabus itself , rather the way in which syllabus is set. Let us look at CUSAT syllabus for Electronics and communication. ( Sorry, I can’t find it on the Cusat website. I have placed the 2006 Btech Scheme and syllabus for Electronics and communication here.).

See the 5th semester microprocessor laboratory.

PART II – 7 Lab sessions
1. Introduction to IBM/PC and its DEBUG program commands
– Examining and modifying the contents of the memory
– Assembling 8086 instructions with the ASSEMBLER commands
– Executing 8086 instructions and programs with the Trace and GO Command.
– Debugging a program
2. Assembly language program development using IBM/PC Macro assembler
– Creating an Assembler source file
– Assembling source program with MASM
– The link program – creating a RUN module
– Typical programming examples.

The DOS debug and masm are embedded in the syllabus itself.

Similarly look at Signal Processing Laboratory. 7th Semester

1. Familiarization of Signal processing tool box-MATLAB
2. Familiarization of DSP trainer kit (Sampling & reconstruction of signals)

List of experiments to be implemented

Generation of basic input signals ( both discrete & continuous)
DFT and spectral analysis computation of DFT, properties of DFT
Digital filter design- FIR & IIR Filters
Spectral estimation
Matlab is specifically mentioned even though all the above can be done in Octave or Scilab. I don’t know why it was not mentioned.
When we had a university inspection some time back , the inspection committee specifically asked for the Matlab license.

The syllabus revision committee generally consist of senior faculty mem4bers. Most of them are included in the committee on political lines on on merit. Kerala may be the only place in the world where you will find things like Turbo C , debug etc are taught to engineering graduates.

New Antenna mast at VU2SWX

A new antenna mast was installed at VU2SWX  ham radio station. The Mast is approximately at a height of 18 meters from ground level. The following photographs show the installation.

Antanna base

The base of the mast.  It consists of 1.5m  2 inch GI pipe  fixed on  parapet. It is also  bolted to the side wall. The  bottom side is fixed on a concrete block.

Antanna base at vu2swx

Another view of the base.

top of the mast at vu2swx

The top  end of the mast. It has a pulley attached to a piece of pipe as shown.  Another piece of pipe was welded above the triangular piece to fix a VHF vertical dipole.

hooks on the mast for guy wire

The  hooks on the mast for guy wire. The actual mast is fabricated from 4 pieces of GI pipes. Each piece can be detached if needed.

Antenna  mast installation

Starting the installation. The installation was some what tricky. There is a power line near my house. So the  guy wire were attached to hooks so as to avoid  the possibility of any  electric shock.

Antenna mast

The mast  going up along with guy wires. The  guy wires were loosened as it went up.

Antenna mast fixing

Fixing the mast to the base.

Antenna mast  guy wires

It is going up.

Antenna mast installation

Fixing the base.

Antenna mast

It is almost there.

Antenna mast at vu2swx

A view of the mast.

Antenna mast at vu2swx

After the installation.

There are 4 guy wires. The guy wires are isolated  from ground via a piece  of PVC pipe  The guy wires were tied to  hooks on the terrace. There is a nylon rope on the pulley so that I can easily  mount an inverted V for HF bands.  I am yet to fix the antenna. Hopefully, I will be QRV by the  end of my vacation.

Update. 28th April 2009

My friend  OM VU3RDD wanted to look at  VU2SWX  mast for ideas  and a game plan for  a mast he is planning. So I have set up a picasa webalbum here.

Building Bitx part-1

   Bitx 20 is a cute QRP transceiver for 20m. The original Bitx 20 was developed by Indian engineer Ashar Frahan. The details of the circuit and other details  are available at his website. There is an active yahoo group for bitx builders and  there are several mods and add-ons  developed by bitx enthusiast all over the world.

  I am already having a Bitx20 and I have made contacts  with several European and Russian  amateurs on 20m.  I have been  thinking about  building a  modified version  of  bitx for 40m  for quite some time now.  Now that I am on vacation, I have started working on this project last night.   I am following the version 3  layout as  prepared by VU2WJM OM Rahul for this.   The diagram is here.

I will describe my progress  along as i build here.

   For converting the Bitx 20 to 40m two modifications are to be done. The band pass filter must be redesigned for 40m and the VFO must oscillate around 17MHz.  I am planning to get the transceiver working for 20m and then replace the VFO and band pass filter.

I am following ugly construction method for this project.  In ugly construction a plain copper clad sheet is used as a ground plane. All components having connection to ground are soldered on to the copper clad sheet. All other connection are between component leads and not supported on the board.

The  following  photographs show my  progress so far


  The  microphone amplifier.

This stage was  built first and tested  by injecting a 50mv 1Khz signal from a signal generator. The stage was giving a gain of nearly 10.


Bitx beat frequency oscillator

I built the above stage next  and  powered up. The waveform was observed on a CRO and frequency measured with a frequency counter. I was able to vary the oscillator frequency about 20khz by turning the trimmer.

The next step was to wind the trifilar transformer for the mixer.  The details are shown below.



Take approximately 105cm of 29 SWG enameled copper wire. Fold them into three as shown above.


Twist  the wires together.


Wind 13 turns into a toroid. You can use a TV balun . In that case choose  smaller wire  diameter( something like 32SWG).  Cut the ends of the  wires and isolate the three windings. Identify the ends of the windings with a multimeter and mark the windings with marker pen. (You need at least 2 colors). Now the transformer can be installed. Be careful about the polarity of the windings.


The bitx mixer installed on the board.

  I will describe further progress later

The online method of finding fair value of land in Kerala :D

             The registration department of Kerala has launched a web site which lists fair value of land in various parts of Kerala. Here is a report about the inauguration of the site . Being a land owner( and,of course a member of the so called land mafia), I was eager to find out the fair value of some of my property.

At 2.30 pm on 29th May 2008, I got the following screen.



I had a different screen in the morning, but could not go beyond the starting screen.

This is a classic case of Kerala Government web sites getting failed on the very first day of operation. The fair price of land being a sensitive issue, the the server might have got fairly good amount of hits this morning. The sys admins of most of the government websites are unaware of issues like slashdot effect.

Ok. Let us find out what this is.

sunil@debian:~$ nslookup

Non-authoritative answer:

Browsing to also gave the above page. Hence, it is assumed that the domain is hosted on a dedicated IP.

Let us run nmap and find out what OS is being run.

debian:/home/sunil# nmap -P0 -sV -O -v

Starting Nmap 4.11) at 2008-05-29 20:07 IST
DNS resolution of 1 IPs took 0.00s.
Initiating SYN Stealth Scan against [1680 ports] at 20:07
Discovered open port 80/tcp on
SYN Stealth Scan Timing: About 39.46% done; ETC: 20:09 (0:00:46 remaining)
The SYN Stealth Scan took 84.78s to scan 1680 total ports.
Initiating service scan against 1 service on at 20:09
The service scan took 6.29s to scan 1 service on 1 host.
Warning: OS detection will be MUCH less reliable because we did not find at least 1 open and 1 closed TCP port
For OSScan assuming port 80 is open, 35912 is closed, and neither are firewalled
Host appears to be up … good.
Interesting ports on
Not shown: 1679 filtered ports
80/tcp open http Microsoft IIS webserver 6.0
Device type: general purpose
Running: Microsoft Windows 2003/.NET
OS details: Microsoft Windows 2003 Server SP1
TCP Sequence Prediction: Class=truly random
Difficulty=9999999 (Good luck!)
IPID Sequence Generation: Busy server or unknown class
Service Info: OS: Windows

Nmap finished: 1 IP address (1 host up) scanned in 94.289 seconds
Raw packets sent: 5074 (224.128KB) | Rcvd: 27 (1875B)

The server is running widows 2003 server. I was under the impression that all the Kerala government sites are on free software.

I did some more research on some prominent Kerala government sites and I feel most of them are vulnerable. Some of them running unwanted services, open relays,outdated software etc. Try running nmap on a couple of them. No wonder they get hacked so often.

Let us wait and see how the registration department web site will come up.

Update 8pm 29 may 2007:

The site is back online.

Here is a screen shot. Even though  it is showing server busy, I could access records from the site.


            There is a detailed  page here on how to access your lands fair value.  Now look at the front page there is a user login box  on the right side. Click on the user drop down box. All user names are listed. This seems to be for  data updation  from various district offices. 

          Now, select any user from the  list, click on the  forgot password link.. :d  Tomorrow  each of the users will see  thousands of mails announcing change of password.

Software defined radio with web interface

The folks at University of Twente has installed a software defined radio receiver and connected the same to internet. I have been listening to this radio for quite some time now. You don’t need an amateur license to listen 😀 to it.( so give it a try) The receiver can be accessed from here . This SDR can be tuned to 80m 40m and 20m. It has got excellent signal quality and runs on minimal hardware. Look at this picture to see how simple an SDR can be. Detailed information of the set up is available here