TT’s Jottings-Blog of VU2SWX

   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 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 http://igr.kerala.gov.in is.

sunil@debian:~$ nslookup
>
> igr.kerala.gov.in
Server: 202.88.238.3
Address: 202.88.238.3#53

Non-authoritative answer:
Name: igr.kerala.gov.in
Address: 210.212.239.30
>

Browsing to http://210.212.239.30 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 igr.kerala.gov.in

Starting Nmap 4.11) at 2008-05-29 20:07 IST
DNS resolution of 1 IPs took 0.00s.
Initiating SYN Stealth Scan against 210.212.239.30 [1680 ports] at 20:07
Discovered open port 80/tcp on 210.212.239.30
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 210.212.239.30 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 210.212.239.30 appears to be up … good.
Interesting ports on 210.212.239.30:
Not shown: 1679 filtered ports
PORT STATE SERVICE VERSION
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.

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

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

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 .