Circuit Fun

What was that line from the movie.. “I love the smell of solder in the morning….

My trusty Ol`Weller - since 1970...

My trusty Ol`Weller - since 1970...

Call me old-school if you like, but soldering circuits is great fun. I’ve had this same soldering gun since sometime in high school, maybe 1970.?. I knock wood, but this ol`Weller has never failed to make a good joint. The proto socket is for sure to be the best way to work out details before committing to soldering components to the board – that’s the easy part. The fun is working out which leg to put into which hole to take up the least space on the final piece of circuit board ‘before the soldering’.
prototype circuit layout

prototype circuit layout

This particular circuit is to interface a computer’s sound card audio output to a transmitter’s PTT input, otherwise known as a Voice-Operated Switch or VOX. In this case the audio will be AFSK or other digitally encoded bit stream, instead of a voice. The circuit details were provided by Skip Teller – KH6TY in the June`2009 issue of QST magazine, on page 30. Of course, I have to add a status LED, and make adjustments for any custom components from my junk box.. Using such a switch removes the need to use a COM port for Tx keying. In my case I intend to use this on my APRS station, with an older model Kenwood 2m rig that can provide the needed +VDC via the mic connector. Skip has contributed greatly to the development of numerous software tools now available to ham operators for digital messaging. Some may remember ‘digipan’ as an early PSK31 package introduced by Skip. A more current package is NBEMS which can be used on HF or VHF, and is being accepted and deployed by many ARES groups. From the web site :

A collaborative effort of W1HKJ and KH6TY. NBEMS is a suite of programs that provide error free transmission of text, images and email files. Fldigi and Flarq are designed to run in Linux, Free-BSD, XP, W2K and VISTA. NBEMS is the packaged Windows version of flarq, and fldigi.

Build some of your own stuff, have some circuit fun for yourself. Try some NBEMS today ! Thanks to Dave, Skip, and a bunch of beta-testers; we have a great software package (that works when all else fails) – anyone can do this.


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