Saturday, April 7, 2012

The Improved Neophyte Receiver: Part 2

I searched my archives for a suitable S-Meter circuit and it turns out that I had one in my Project Box. I have a Project Box that I keep kits in for future needs. One of the kits that I had was the Kanga Products "Audio 'S' Meter." The box was down in my basement and I had completely forgotten about it.

According to Kanga Products,
"Most homebrew receivers and transceivers lack any form of 'S' meter. They are not difficult to build but finding a suitable circuit that works is often a problem. This circuit is based loosely upon one from Doug DeMaw W1FB. The circuit samples the audio of the receiver after the detector, but before the audio volume control. The signal is amplified and rectified to give a DC voltage that varies according to the level of audio."

The enclosure style I have chosen for my receiver is to allow me to easily modify my circuitry until I have locked down my choices for performance and usability. I simply used a block of wood and a piece of artist board that has clay in it to build the reciever chassis. As you can see from the front of my receiver the design is constantly evolving. Do you see the 4 holes in a rectangle shape? I was going to mount the S-Meter circuit there but the spacing was a little too tight and it was interfering with the main tuning capacitor. So I decided to mount the main receiver board vertically and then attach the S-Meter board to one corner of the receiver board.

The next modification I want to make to my 40 Meter receiver is to add a digital frequency dial.