Sound Card Interface

I have always wanted to try using my computers’ sound card along with my HF transceiver to work some of the digital modes as so many others have been doing. Once again a friend of mine had been perking my interest in this mode of communications. I came to realize that all of his many contacts were using digital modes such as CW, RTTY, PSK31 etc. During a recent Ducie Island DXpedition that had been activated as VP6DX, I saw where they were making CW and RTTY contacts as well as phone so now was my chance. I perused through several magazines and books that I had on hand but didn’t come across anything that I cared to build. Searching the Internet I came across an article entitled “Sound Card Packet Interface” by KD5ZUG. This looked very promising plus there was an added benefit, there was a full size printed board circuit layout along with the article.

I made the circuit board using the same procedures posted in another article found on the Holiday City website entitled "Easy Printed Circuit Board Fabrication" . The board turned out well on my first attempt so I went on a scrounge mission to get the other parts I needed for the project. I located just about all of them on several old scrapped circuit boards and I placed an order to Mouser electronics for the rest. During final construction I realized that the CW mode would be in keying the transmitter and sending all the dit’s and dah’s as audio and not actually keying the transmitter as you would with a set of paddles or a straight key. I made a modification to the project to allow for this. I utilized a computer A/B switchbox to house the project. You can find the original article on the Internet at the following location. http://www.jbgizmo.com/page28.htm I hope you try this project and you are as happy with it as I am. During the VP6DX DXpedition I used this project to log all of my digital contacts.

73 for now,

Steve, N2WLH