Ashhar Farhan VU2ESE

BITX - the bidirectional transceiver

You are probably here because you heard of the BITX transceiver. Read the entire article here.

BITX is very actively discussed by builders and kitters on http://groups.yahoo.com/groups/BITX20. Join it to get help, meet and discuss with other BITX builders.

JBOT - An easy QRP liner amplfier

This is a 5 watts linear power amplfier made from a bunch of 2N2218s.
It is an easy, inexpensive project that provides linear and stable performance.
Read the article here »

A Homebrew Signal Generator

Trying to design and align RF filters I needed a stable, clean and 50 ohm impedance signal generator.
This is a simple generator built inside a PC power supply box. If you are serious about homebrewing, you will need an RF signal generator.
Try this one »

A 40M Direct Conversion receiver

I helped my cousin with her school project to make a direct conversion receiver.

I wrote this article to document how we went about constructing it. Newbies might find it an interesting project.

Read the write-up here.

A 40/20 SSB transciever

I made a dual band transceiver as an evolution of the simple S7C receiver in EMRFD. It remains my favourite with it's really clean receiver output. It has far too many relays to do bandswitching though.

Many people have asked me for the SSB transceiver details. Check it out.

What's New?

I recently made a signal generator for experimenting with RF filters, antennas, measuring impedances, Qu of coils etc.
It is a simple weekend project that can make your homebrewing more educating and entertaining. Read about it ».

A year ago I tried writing a blog, I discovered that it wasn't optimal for what I was trying to do. Instead, I have reformatted those texts as articles. Hopefully, I shall add more of them with time.

The Homebrewer's Lab
If you were just starting out with homebrewing, what would you need to test and build? What should your junk box hold? Which iron? Oscilloscope?
Here is my take.
Measuring Inductance with a frequency counter
By constructing a simple two transistor oscillator, you can measure any RF inductance. Now, you can wind your inductors on anything from film roll boxes to tap washers.
Here is how »
How to design an SSB crystal fitler
I have an oversimplified method that's 'cut' only for 10MHz crystals. It's a part of a larger article about a dual-band transceiver.
Read it here.
A DSP Shell
I needed a DSP shell to experiment with SDR algorithms. Instead of purchasing the ADSP board, I decides to write something that will work on a PC instead. You need to be a programmer to make sense out of this.
Download the sources.

Copyright on this site

All the content of http://phonestack.com/farhan is freely reproducable in any form without requiring any further permission as long as the content is reproduced without any change and the copyright notice states it is freely copyable.

I am thankful to my company Phonestack to allow me to host these pages. The grant of the above copyright does not extend to the rest of the Phonestack site ofcourse, but is limited to only the content of www.phonestack.com/farhan (my personal site).

This is the current view of my work bench as on April 24th, 2008.

Except for the Tektronix 465, everything is homebrewed. Next to the scope, the three boxes are the bench power supply (a car charger with a fat 78H12 added), a homebrew signal generator and a PIC based frequency counter. On the right are two boxes with standard resistors and capacitors. On top of them is a clay Buddha made by daughter and the DC40 receiver mentioned on this page.

I use a small halogen table map to light up my work area and a number of candy boxes to keep my components. I prefer keeping them open, making it easy for me to spot them.

On the bench is a small circuit that I am using to measure the Qs of some coils.

Write to me at 123farhan123@phonestack.com. Remove the digits in the email, they are meant to confuse the programs that automatically gather email addresses from the Net.