Archive for May, 2008

Building Bitx part-1

May 30th, 2008 3 comments

   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

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

May 29th, 2008 1 comment

             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

May 26th, 2008 Comments off

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

Bus Route Numbers Introduced in Trivandrum

May 22nd, 2008 15 comments


For the benefit of tourists, the Kerala State Road Transport Corporation has introduced bus route numbers in Trivandrum. I spotted some buses proudly displaying their numbers today.
But I could not find the complete list of numbers anywhere on the Internet. The official website of KSRTC is nothing but trash. Look for Bangalore or Chennai bus route numbers on google . You will get plenty of information. You can even find applications which look up a route if you give the number like this . I don’t know how the route information in Trivandrum is going to propagate among people unless they publish the complete list.

The list of bus routes as appeared in a local news paper is provided below. I cant attest the authenticity. Happy Journey on City bus.:D

Bus Route Numbers in Trivandrum

Route no Destination Via route
111 Kovalam Beach , Thiruvallam, Pachallur
111A Kovalam Beach Bypass
111B Kovalam Beach Pallichal Venniyyoor,Panagode,Muttaykadu
115 Attukal temple Manakkadu Attukal
136 Venganoor Thiruvallam, Panangode
136A Venganoor Thiruvallam, Agricultural College,Peringamala
143 Peringamala Thiruvallam, Panangode,Venganoor
143A Peringamala Thiruvallam,Agricultural College
149 Vizhinjam Thiruvallam, Pachallor
149A Vizhinjam Thiruvallam,Venganoor
155 Veli Palayam ,Sanghumugham,Vettukadu
155A Veli Valiyathura,Sanghumugham,Vettukadu
155B Veli Palayam, Pettah, All Saints College ,Madhavapuram
151 Sanghumugham Palayam, Petta, All Saints College
151A Sanghumugham Valiyathura, airport
171 Puthenthope Palayam, Petta, All Saints ,Madhavapuram
171A Puthenthope Valiyathura,Sanghumugham,All Saints College
101 Airport Valiyathura
101B Airport Valiyathura, Sulaiman theruvu
161 Kochu Veli railway station Palayam Petta Chakka all saints college
175 Karikkakam Temple Palayam Chakka Byepass
175A Karikkakam Temple Palayam Petta Anayara Venpalavattom
105 Bheema palli Valiyathura
105A Bheema palli Mukkola
105B Bheema palli Kallumoodu
173 KIMS Palayam Petta Anayara Venpalavattom
555 Medical College Palayam Pattom
555A Medical College Palkulangara, Pallimukku Kannammola
555B Medical College Palayam ,Kannammola
511 Akkulam Palayam Pattom Ulloor Kesavadasapuram
511A Akkulam Palayam Pattom medical college
511B Akkulam Palayam Kannamoola Medical college
529 Engineering College Palayam Pattom Ulloor Kesavadasapuram Srikaryam Chavadimukku
529A Engineering College Palayam Pattom Ulloor Medical college
Srikaryam Chavadimukku
543 Chempazhanthi Palayam Pattom Ulloor Kesavadasapuram Srikaryam
543A Chempazhanthi Palayam Pattom Ulloor Kesavadasapuram Srikaryam Akkulam
543B Chempazhanthi Palayam Pattom Ullor medical College Srikaryam
551 Pothencode Palayam Pattom Ulloor Kesavadasapuram Srikaryam Paudikonam
552 Santhigiri Palayam Pattom Ullor Kesavadasapuram Srikaryam Pothencode
552A Santhigiri Palayam Pattom Ulloor Medical College Srikaryam Pothencode
581 kazhakkoottam Palayam Pattom Ulloor Kesavadasapuram Srikaryam Karyavattom
581A kazhakoottam Palayam Pattom Ulloor Kesavadasapuram Srikaryam Kulathoor
585 Kaniyapuram Palayam Pattom Ullor Kesavadasapuram Srikaryam Kazhakootam
585A Kaniyapuram Palayam Pattom Ulloor Kesavadasapuram Srikaryam Kazhakootam ChanthaVila
404 Peroorkada Palayam Vellayambalam Ambalamukku
404A Peroorkada Nanthancode
404B Peroorkada Sasthamangalam Paipinnoodu
421 Vellanadu Peroorkada karakkulam Erumba Aruvikkara
429 Aryanadu Palayam Vellayambalam Sasthamangalam Vattiyorrkavu nettayam
429B Aryanadu Jagathi Poojapura Peyadu Vilappilsala Uriyakode
434 Nedumangadu Palayam Vellayambalam Kavadiyar Peroorkada
477 Aruvikkara dam Palayam Vattiyoorkavu Nettyam
477A Aruvikkara dam Palayam Vellayambalam Kavadiyar Peroorkada Erumba
477B Aruvikkara dam Palayam Vellayambalam Kavadiyar Peroorkada karakulam Azhikode
493 Puliyarakonam Palayam Vellayambalam Sasthamangalam Vattiyorrkavu Vellaikadvu
493A Puliyarakonam Jagathi poojapura peyad
493B Puliyarakonam Palayalm Pangode thirumala Peyadu
197 Malayinkeezhu Karamana Pappanamkode Malayam
197M Malayinkeezhu Jagathi PeyaduKolachira
399 kattakada Palayam Bakery DPIThirumala Peyadu
399B kattakada Palayam Bakery Pangode Thirumala Peyadu
501 Vikas Bhavan Palayam
631 Vattapara Palayam Pattom Kesavadasapuram Mannathala
631A Vattapara Perrokada Kudappanakunnu Mukkola Kallayam
647 Venjaranmoodu Palayam Pattom Kesavadasapuram Mannathala Vattapara Vembayam
647A Venjaranmoodu Palayam Pattom Kesavadasapuram Mannathala Vettinadu Knochira Velavoor
647B Venjaranmoodu Palayam Pattom Kesavadasapuram Sreekaryam Paudikonam
191 Pappanamkode Karamana
299 Neyyattinkara Karamana Pappanamkode Pravachambalam Balaramapuram
299A Neyyattinkara Karamana Thirumala Peyad Malayinkeezhu Oorootambalam Vandannor perumpazhuthoor.
581B Kazhakuttom Palayam Pattom Medical College Ulloor Sreekaryam Kulathur
581C Kazhakuttom Palayam Kannamoola Medical College Sreekaryam Kulathur
581J Kazhakuttom Palayam Petta Anayara Bypass
585E Kaniyapuram Eenchakkal Bypass Technopark Kazhakuttom

The RGB LED project

May 19th, 2008 1 comment

Four sixth semester students from Model Engineering College has done a small project titled the RGB Led project. They have blogged the development and published the programs and schematics.  I have been going through the site today and I feel that this is the way students do their minor project.

There is nothing complicated in their circuit. They just use commonly available chips and wrote a small piece of software. They have also published the final report. Well done.

The RGB led is  a cute component  that any hobbyist will love to posses.  I have a couple of them lying in my junk box. After seeing this project , I think I will try out one of them .