Software Defined Radio

Hams: Click here for my notes on connecting FlexSDR to FLDIGI


 The virtual front panel of a Software Defined Radio (SDR)

The new frontier in radio communications is Software Defined Radio. Instead of having a piece of hardware that looks like a radio, with dials, buttons and a display readout, there’s just a plain box. Mine is blue and about the size of a 100-sheet pack of printer paper. It came from a company called FlexRadio and it cost about $1800. This box has connectors for a computer, an antenna, power source, microphone, Morse code key and headphones or speakers. That’s it. No adjustments. No tuning display.

Hook up all the wires, push the power button and the indicator light turns on. Nothing else happens. In SDR, everything happens in the computer software.

So you download the free software from the company site, follow the straightforward directions, and a radio front panel appears on the monitor. It’s impressive, with a beautiful frequency readout down to 1 Hz, a panadaptor waveform window and more buttons than any normal mortal could figure out unaided in a month.

Click on the power switch icon and the blue box comes to life. Sounds pour out of the speakers. Scroll the mouse wheel up and down and you’re tuning across the band. Click on a button to go to the ham band you want to use and you’re there. Click to change from single sideband voice to CW (Morse code) and it’s ready to go. Click on the automatic antenna tuner and it’s ready to transmit. It even tells you what license is required for each band segment and identifies shortwave broadcast bands.

And that’s just the start. It’s an incredible receiver, with adjustable filters that slice away everything you do not want to hear. You can configure the transmitter to fit your voice exactly until it sounds like you at the other ham’s station. It can receive and decode any type of transmission you might receive. It links to a computerized logbook to automatically record the frequency and time of the stations you contact. It links to digital radio software like FLDIGI or Ham Radio Deluxe to adapt to any mode of communications: PSK31, CW, RTTY…

The best part is that it cannot become outdated. If hams decide to experiment with a new technology, all it takes to try it yourself is a software update.

I’m hooked. This is the most fun I’ve had with ham radio in many years.

1 Comment on “Software Defined Radio

  1. That is really awesome, I have been thinking about taking up the hobby someday so next time I’m down in Maryland I’ll have to check out the old and new hams. I remember listening to you on the one in your car when I was a kid and I always thought it was so cool. Talk to you soon!

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