The amazing world of SDR on a budget...

If you’re the obsessive type – like me – some aspects of hobby radio are frustrating, especially when computers are involved. On the other hand, with patience and effort, frustration can lead to reward. Sometimes.

I found this to be true of my latest obsession, software defined radio (SDR), where the controls of a radio receiver (or transceiver) appear as beautifully rendered graphics on a computer, while the hardware resides on a thumb drive plugged into the USB slot.

After marveling at these devices for years, I finally broke down and ordered one of the cheapest I could find on Amazon.com - the NooElec NESDR Mini USB RTL-SDR, complete with a tiny mag-mount antenna - for under $20 (plus shipping). I also ordered a plug adapter to be able to use a conventional coaxial connector and an outside antenna.

NooElec SDR dongle and mini antenna.

Sound easy? Not so much. SDR dongles are NOT plug and play and the computer won't find the drivers for you, as it would for common hardware like printers.

The NooElec dongle works with lots of different software, and the company provides links to freeware and also the RTL driver that you need to make it play correctly.

With a Google search, I found an even bigger list of RTL-SDR software, appropriately titled "The Big List of  RTL-SDR Supported Software." 

Amazed by all the choices, I decided to try my hand at “SDR Sharp,” which has a professional look and lots of different modes, filters and display options.

Sitting at my 64-bit Windows 10 computer, I followed the instructions to the letter, downloaded and unzipped the files and dragged in the RTL driver. After opening the .exe file, the radio installed before my eyes and a beautiful interface opened on my screen.

Screen capture of the SDR Sharp radio software.

With trembling hand (alright, my hand was steady but I have a flair for the dramatic), I plugged in the dongle (for a second time – you also need to plug it in briefly before software installation), made sure the mini antenna was connected, and pressed “play.” A live radio waterfall appeared and static hissed from the speakers. Success!

Since that moment, I have been getting used to the many settings of SDR Sharp. There is variable RF gain, band spread and wide-narrow bandwidths – NFM for communications, WFM for broadcasting and AM for VHF aviation, There is also sideband and digital modulation modes that I haven’t tried yet.

NooElec claims the dongle receives in the range of about 25–1700 MHz, but I mostly listen to the VHF high, aviation and UHF bands (with an external antenna) and find the radio to be sensitive and robust at those frequencies. Listening to FM broadcast radio is a treat because stations are picked up in stereo AND the with RDS information. 

The Big List of RTL-SDR Supported Software also includes plug-ins, that can enhance the radio in areas like aviation tracking and trunk system monitoring. To use the dongle on shortwave, you can buy another piece of hardware called an "up-converter" for around $40. Sounds like a sensible investment to me.

73, Pete Miller