Software Defined Radio (SDR) category

Software-defined radio (SDR) is a radio communication system where components that have been traditionally implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented by means of software on a personal computer or embedded system.

Experimenting with software defined radio used to be expensive, but now it is cheap. Nowadays it is very cheap to start experimenting with SDR. Most receivers use a variable-frequency oscillator, mixer, and filter to tune the desired signal to a common intermediate frequency or baseband, where it is then sampled by the analog-to-digital converter. Cheapest wide receiving range well working device is to use suitable DVB-T receiver stick (10-20 Euros/Dollars) and suitable software (very many alternatives, for example SDRsharp and Gnu Radio).

My article Software defined radio with USB DVB-T stick started the long list of SDR related postings. The newest postings now are Filter measurements with RF noise source and Antenna measurements with RF noise source.

2 Comments

  1. Tomi Engdahl says:

    Shmoocon: Delightful Doppler Direction Finding With Software Defined Radio
    https://hackaday.com/2018/01/23/shmoocon-delightful-doppler-direction-finding-with-software-defined-radio/

    When it comes to finding what direction a radio signal is coming from, the best and cheapest way to accomplish the task is usually a Yagi and getting dizzy. There are other methods, and at Shmoocon this last weekend, [Michael Ossmann] and [Schuyler St. Leger] demonstrated pseudo-doppler direction finding using cheap, off-the-shelf software defined radio hardware.

    The hardware for this build is, of course, the HackRF, but this pseudo-doppler requires antenna switching. That means length-matched antennas, and switching antennas without interrupts or other CPU delays. This required an add-on board for the HackRF dubbed the Opera Cake. This board is effectively an eight-input antenna switcher using the state configurable timer found in the LPC43xx found on the HackRF.

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  2. Tomi Engdahl says:

    SDR’s Hard Side Shown in DARPA Hackfest
    https://www.eetimes.com/author.asp?section_id=36&doc_id=1333114

    A DARPA program manager shares experiences from a hackfest he hosted on software-defined radio (SDR) and drones in Silicon Valley last fall.

    When I was running the GNU Radio Project before my current gig at Defense Advanced Research Projects Agency (DARPA) began in 2016, I found it useful to bring the core developers from around the world together for a few days for what we referred to as our “hackfests.” These gatherings gave us an opportunity to break away from our offices and day-to-day responsibilities to work out some of the larger technical problems we were facing in the Project.

    During these few-times-a-year hackfests, we worked crazy-long hours, lived on fast food, and de-prioritized sleep– an energizing combination that fostered collaboration and focused our attentions in uniquely fruitful ways. As a result of some of our hackfests, core and prominent features were created that still reside inside GNU Radio today.

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