What use is an F-call?

If you've ever sat at home wanting to listen to HF but you're radio is out of commission, worse still, you haven't yet got a radio, or your antenna is a project in progress, I stumbled on a way to have your cake and eat it too.

I was hunting for examples of a pile-up and I'd found in the past radios that had been hooked up to the Internet that you could tune and listen to. Today I stumbled across something of a different magnitude altogether. Something called Software Defined Radio on the Web, or websdr.

A group of amateurs at the Technical University of Twente put up the worlds first websdr in 2007. It was conceived in an attempt to connect the 25m radio telescope in Dwingeloo to the world, for radio amateurs doing Earth Moon Earth or EME contacts, it snowballed from there.

So, now you can go to websdr.org, pick from a list of 40 receivers around the planet and listen to what ever frequency is within the station's range. The Twente receiver does 0 to 29MHz, there are UHF, VHF and GHz receivers to be found. The software runs a Java Applet that sits in your web browser displaying either a waterfall or spectrum scope and you can see the whole band at the same time.

On your normal radio, you tune to 7.093 and have a listen. If you hear nothing, you move the dial and try again, rinse and repeat until you hear a station calling CQ. With SDR, you can see all frequencies at the same time. The software allows you to switch between modes, so you can decode the signal as AM, LSB, USB, FM, CW, what ever you want. You can set the bandwidth and play with the tuning, all while others are doing the exact same thing on their computer with what ever frequency they're using.

Your own radio does one frequency at the time, SDR does them all at the same time and you can zoom in and out, scan around and find the elusive 10m contacts. With one look at the display you can see if 10m is active right now, or if it's a dead duck.

The web site again is websdr.org, check it out, use it to tune your pile-up skills for the next contact, or use it to find a station you like, turn on your own radio and have a QSO. Nothing stopping you from turning on several, all tuned to the same frequency and see what the propagation around the world is like either.

I'm Onno VK6FLAB