About two years ago I became infected by SDR, Software defined Radio. SDR is definitely the greatest improvement in ham radio I have seen so far. The good thing is, that we are just at the beginning. SDR started just a couple of years ago with the famous QEX articles by Gerald Youngblood, K5SDR where he described an SDR radio for the masses.
In this article series, which consisted of 4 parts, he described the theory behind the quadrature samling detector, QSD. He showed how to build up a QSD and how to write a basic software using the PC’s soundcard for decoding.
Meanwhile K5SDR created a serious company, called FlexRadio where he sells a variety of SDRs. However, the low cost version of an SDR has been formed as a project called Softrock which is lead by Tony KB9YIH.
Apart from the QSD principle, other receivers have been developed lately as well. Just to name a view: Q1SR, Perseus, etc. They use more Analogue Digital Converters (ADCs) and have the advantage to cover directly a wide frequency span, without the necessity of further soundcards.
I think the time of new SDR applications, has just started. With CW-Skimmer, a software written by VE3NEA you can decode for example a whole band with up to a few hundred CW signals at the same time. This is just the peak of the iceberg. In my opinion, SDR will make our hobby again much more interesting.
I’m currently writing on my blog almost weekly about ongoing SDR projects or interesting SDR articles I find on the web. You should definitely have a look on my blog. check it out at: http://www.dh1tw.de. If you like the articles, I would be glad to get some feedback. Just leave me a comment with your thoughts!