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SDR - Software Defined Radio

TechEkspert 9834 17
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  • SDR - Software Defined Radio
    Structures with inductance in the diagram are often troublesome to commissioning for electronic beginners. Some people can easily go through the stages of building AM receivers to superheterodyne receivers, for others it is a difficult barrier. Ready-made radio modules are a significant facilitation, for example, allowing for easy activation of digital transmission in ISM bands.

    A step further is SDR - software defined radio. The SDR receiver is usually based on a ready module supplying digital samples of I and Q signals. These samples come from mixers, on which the input signal and orthogonal signals from the local PLL generator were fed. The rest happens in the software processing I and Q signals. Sounds complicated, but we use such a solution, for example, when watching DVB-T TV on a broadband USB receiver and software installed on a laptop.

    What do you think about SDR receivers, do you prefer a traditional receiver design for specific bands or broadband SDR?

    Due to the mass production, USB DVB-T and DAB + receivers are very cheap. The receivers are miniature, powered from USB and cover the band from several dozen MHz to 1.8 GHz. It turned out that RTL2832U-based receivers can provide I&Q samples for use in a program other than that provided by the manufacturer for television and radio reception. This enabled hobbyists to receive signals on the amateur bands, as well as, for example, NOAA satellite weather maps, signals from ADS-B transponders, meteorological radios and many others.

    Usage programs type SDR # , HDSDR , GNU radio and a USB receiver for several dozen zlotys, allows you to start the listening receiver. You can find quite good descriptions of the launch here: RTL-SDR . Such a receiver can be helpful in many cases, e.g. for starting radio modules for digital transmissions. Application examples: https://www.rtl-sdr.com/about-rtl-sdr/
    For more demanding customers, more expensive devices with the ability to work from single KHz to 2GHz have appeared https://www.sdrplay.com/rsp1a/, https://airspy.com/airspy-hf-plus/ as well as devices with the 1MHz to 6GHz range and the possibility of broadcasting, for example, https://greatscottgadgets.com/hackrf/, but in basic applications a "dongle" for PLN 40-60 is sufficient.

    The use of the USB DVB-T receiver requires the installation of the appropriate driver: https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/

    On this page: http://www.websdr.org/ you will find SDR receivers that enable online listening via a browser. Some receivers listed on the website are located in Poland.

    Do you have experience with SDR receivers, what do you use them for?

    Source:
    https://www.rtl-sdr.com/
    http://www.websdr.org/
    http://www.hdsdr.de/

    Cool? Ranking DIY
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    TechEkspert
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    TechEkspert wrote 4433 posts with rating 3633, helped 12 times. Been with us since 2014 year.
  • #2
    prosiak_wej
    Level 38  
    A few years ago I bought an SDR dzyndzel, played with it a bit, and finally got the ADS-B receiver on for Flightradar24. For almost a year I have a factory receiver from FR24 and the dzyndzel serves only as a holder for hanging the Uniden scanner. Maybe in spring or summer I will run it in some interesting band :)
  • #4
    ZimnySobi
    Level 9  
    I have a Tuner with RTL NotOnly TV - LV5DX and on an antenna made by myself at work, I could listen to radio almost 200-250 km away from my location. The same soft and drivers for this USB device, this device because it was not suitable for watching TV with DVB-T, the application hung until it died completely. One of my friends on the plane was listening to the cockpit on a laptop and an antenna from a paperclip. So a little but crazy ...
  • #5
    prosiak_wej
    Level 38  
    For listening to the cockpit, a small Uniden with programmed frequencies used on a given route and a handset in the ear is more convenient.

    In my attic I have a simple dipole tuned slightly higher than the airband, but I sometimes hear the T sector (Wrocław), J (Katowice) or even R (Radom). On the other hand, set to listen on frequencies 132.700, 134.925, 129.075, 130.875, 127.275, 119.650 and 118.100 sometimes he talks a lot, you can listen in the background when doing something :)
  • #6
    c2h5oh
    Moderator  
    Maybe it is worth promoting what is on the electrode instead of presenting old "news" from the world?
    The discussion on this topic has been going on since 2012:
    https://www.elektroda.pl/rtvforum/viewtopic.php?p=11180605#11180605
    The topic is quite long, but contains many solutions to the problems that you will have to deal with when starting this type of receiver. It also describes, for example, the issues of shielding, interference, preamplifiers, antennas and the latest curiosities in this field.
  • #7
    TechEkspert
    Editor  
    @ArturAVS I suspect that not only I missed the mentioned topic in radio engineering. I think that SDR will interest not only amateurs. Once, I had the opportunity to test a bit more advanced SDR and I believe that the practice and knowledge gained even from SDR for PLN 50 can be transferred and used in other more advanced SDRs.
  • #9
    arordrg
    Level 13  
    Last year I bought "DVB-TE4000 USB DVB-T + RTL-SDR Realtek RTL2832U + R820T DVB-T Tuner Receiver". I played a few days and is lying. Works well in the FM, air and police bands. Unfortunately, you can't hear anything on the CB band (although theoretically it can). Works with PC (win and Linux) and android phones (same, high frequencies work with CB not anymore). I also tested the DAB. It works, although I'm far beyond the range of the transmitter, but I live quite high up.
  • #10
    zworys
    Level 39  
    arordrg - below 30MHz you must have a converter. Not every module wants to work in this band despite formal data that it works properly.
  • #11
    nocot
    Level 7  
    I bought an RTL2832U fascinated by the ability to listen to virtually any band from 24 MHz to 1.7 GHz. Unfortunately, the joy ended after firing SDR # because it turned out that this radio does not receive anything but the strongest FM FM stations. No CB, air band, amateur radio, or anything else that should normally be heard on an ordinary receiver. Silence everywhere and sometimes rumble on different strands. For me, it's a waste and a waste of money.
  • #12
    arordrg
    Level 13  
    nocot wrote:
    Silence everywhere and sometimes rumble on different strands. For me, it's a waste and a waste of money.


    I assume that you have connected a better antenna than the one included in the set? Mine was so hopeless that it broke on the first day. Check the antenna adapter if necessary.
  • #13
    sq1gpr
    Level 12  
    Extending the topic with transmitting devices - I built and launched a transceiver for bands from 160 to 10m. The device is called Avala-01 in the network you can find descriptions and diagrams. Construction and commissioning did not cause great difficulties, and I am not a particularly experienced constructor. Certainly, building a multi-band trx in traditional technology would be a much more difficult task. The device works very well, the reception is better than on the factory equipment I have. But this is not due to the trx itself, but to the signal processing performed by the sound card.
    Here you can see what it looks like:

    Link
    Link
    Link
  • #14
    TechEkspert
    Editor  
    Advanced design, maybe worth presenting in DIY .

    Connecting a laptop gives great flexibility, but there are also compact designs:


  • #15
    sq1gpr
    Level 12  
    The Avala project is already a few years old, in the meantime devices that do not require a sound card and a computer were created. By observing and reading about news in radiocommunication, you can see that the future belongs to SDR. For example, radio stations for the army produced by Radmor are only SDRs.
  • #16
    rosomak19
    Level 22  
    nocot wrote:
    I bought an RTL2832U fascinated by the ability to listen to virtually any band from 24 MHz to 1.7 GHz. Unfortunately, the joy ended after firing SDR # because it turned out that this radio does not receive anything but the strongest FM FM stations. No CB, air band, amateur radio, or anything else that should normally be heard on an ordinary receiver. Silence everywhere and sometimes rumble on different strands. For me, it's a waste and a waste of money.
    Just don't tell me you wanted to receive something with that funny antenna? I have 2 RTL2832U ordered from China and I have been doing well for so many years. After adding a converter, I receive the entire HF band decoding all digital and analog broadcasts, meteo data (faxes and rtty), digital DRM radio (something similar to DAB), and also CB. On the VHF-VHF band I won't even write because it's too much. Maybe you bought a damaged one, or you naively thought that you would receive something on this pseudoantence. Okay, maybe some strong FM stations will be picked up by.
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