Mid-Priced Hardware Gets Serious About Software Defined Radio

Regular Hackaday readers are used to seeing the hacks that use a cheap USB TV dongle as a software defined radio (SDR). There’s plenty of software that will work with them including the excellent GNU Radio software. However, the hardware is pretty bare-bones. Without modifications, the USB dongle won’t get lower frequencies.

There’s been plenty of other SDR radios available but they’ve had a much heftier price tag. But we recently noticed the SDRPlay RSP, and they now have US distribution. The manufacturer says it will receive signals with 12-bits of resolution over the range of 100 kHz to 2 GHz with an 8MHz bandwidth. The USB cable supplies power and a connection to the PC. The best part? An open API that supports Windows, Linux, Mac, Android, and will even work on a Raspberry Pi (and has GNU Radio support, too).

If you are like us, your brain is already spinning thinking of the hacks you can do with a fairly inexpensive (about $150) receiver that has that kind of range. Of course, you could use it as just a receiver, but it could do a lot more. For example, the second video below shows a ham that uses the device as a panadapter (a ham tool that amounts to a spectrum analyzer that visually monitors the entire ham radio band for activity).

The device has eight different front end filters that it selects depending on your chosen frequency. We haven’t had a chance to try one yet (stay tuned for that), but the specs look impressive–especially for the price. When you think that we’ve seen cheap SDRs make test equipment and even passive radar, you can only imagine what the community will dream up using these boxes.


50 thoughts on “Mid-Priced Hardware Gets Serious About Software Defined Radio

      1. I actually did it because I had no transceiver. I built an entire transmitting and receiving setup in gnu comp, after following the excellent course from michael, on the hackrf site. I only tested minimally, as even with a crummy antenna the one demo I did of transmitting , actually made the repeater surprising. I stopped there because I didnt have the cash to work on filters and proper tools / attenuators etc and live in an apartment so no antenna either.

        1. Thanks for your reply Addidis
          The video shows two different radio gears (the fact that one of these is a transmitter is not important) receiving the very same frequency, with a synchronisation between the RX freq. of the SDR and the VFO of the TS590. That means that HDSDR (the software used in this demo) is able to drive both rigs… easy with the SDR, but definitely not obvious for the Kenwood.
          hope someone will explain this :- ))

    1. “They put out a temporary release with extio support and are actively going to develop a plugin to support the SDRPlay going forward on the new architecture.

      The new software should mean a Linux build as an option, which would be nice. “

      1. 4G (LTE) tends to be available on 800MHz first when deploying for the first time, then the higher frequencies follow up later as the bands become available. GSM goes up to 2100MHz IIRC, perhaps higher if the local geography allows.

        Not sure about CDMA though.

  1. The cheaper RTL-SDR dongles sounds great but you have to use something besides the stock antenna they come with and probably have to get a choke around the usb cable. Mine picks up fm radio stations and noise from my laptop even with usb extension cables. Beyond that not much of anything. So sounds like I’ll have to do some isolation. I was wondering if anyone has tried this SDR Play and if it has some of the same gotchas? Just like to know what I’m in for before I spend the extra money and end up in the same situation.

    1. Some devices just spew out RF. Not much you can do about it in most cases. You can mitigate it with chokes and grounding schemes. I found that I eliminated a great deal of noise by not going through a USB hub or case-front USB slots.

      If you really want to try and filter out noise, make a band-pass filter front-end. There’s not a whole lot to them(minimally). Also, I have noticed with the dongles that there is a LOT of internal noise that is present regardless of the antenna, transmission line, or USB configuration. One thing to do is install a preamp to get the antenna signals above the internal stuff. The noise will still be there, but your signals will be far above it.

    1. Different design, with a LNA to compensate for the lack of sensitivity. In the other hand the LNA cannot be switched off so it overloads easily in presence of strong signals.
      Nice toy, but not so serious about SDR.

      1. Indeed, and the airspy also has lots of breakouts so you can hack your own things on top of it, which this one doesn’t seem to have.
        There are many variation on the theme of SDR and each one seems to have its own peculiarities and strengths and features.

    1. Well at the risk of starting a Mac vs PC or emacs vs VI style set of comments, I’ll interject one quick note on that: When we covered HackRF earlier (http://hackaday.com/2013/08/01/hackrf-or-playing-from-30-mhz-to-6-ghz/) the specs said it bottomed out at 30MHz. They later amended that to 10MHz and then 1MHz (https://greatscottgadgets.com/2015/05-15-hackrf-one-1MHz/). By their own admission, though, you get better performance at higher frequencies. For the SDRPlay, they are quoting down to well below 1MHz. I don’t know if that’s because they have better performance, or if the performance degrades and they just aren’t as obvious about it. However, good performance on the HF bands is very important to many of us. I’m not saying the SDRPlay has better or even sufficient performance there (nor am I saying the HackRF doesn’t have sufficient)–I don’t know the answer to either of those questions.

      I’m just saying that like everything in life, there’s going to be choices and design trades. I haven’t had the SDRPlay long enough to draw any conclusions about it versus the HackRF yet.

      Also, do you know what’s the difference in the “Blue” versions and the $330 version — is it just the case?

      1. [Al Williams] Nah, Most are mature enough to be able appreciate emacs and/or VI. Things would probably get ugly quick if we started arguing about best material for punch cards (hanging chads and all that.). Heh.

        Just a quote from the Blue site (I haven’t verified) from existing owners “200kHz to 7.2GHz (without up/down converters), though the official range is ~5MHz to 6GHz.”

        > is it just the case?
        Yeah, it seems to be it. I’m haven’t held either one but by appearance the RF One looks it’s two pieces. The RF Blue as viewed at the store appears to have the laser cut particle wood sheets.

        I WILL admit it’s nice to have another project or tool to use the SDRPlay certainly is better then a $20 dongle.

      1. [W]

        Valid up to a point. I don’t have a Amateur Radio Operator License either. That said I wouldn’t mind looking at how far along the certification path to earn one. As I understand the first two levels just require interest. The third (and final) classification is passing a Morse code speed and accuracy test (I vaguely recall) and getting your own call sign.

        >TX is of no use to me.

        I won’t sell you on the idea that it is. Just pointing out that $50 isn’t a huge leap to have both RX and TX.

        Maybe you are security minded and wanted to test if your car or home is vulnerable to De_Bruijn_sequence. Maybe find out why your phone keeps dropping to G2 and TX ping triangulate who or what is running a fake tower.


        I mean you COULD skip on the SDRPlay all together and use a $20 dongle and build a TX component.
        The discoveryboard @$12-$25 plus building your own little addon, module (@$ 0.25 – $5). So you’d have saved $125 with just a Simple dongle and Discovery board. (yes, yes, assuming you just wanted to test at the 433Mhz range.)

        I’d be more inclined to compare the SDRPlay and HackRF (either One or Blue, yes the accessories are compatible for both.) like comparing the difference between getting a Raspberry PI or Banana/Orange PI. Sure the Banana/Orange might have X versus Y, power, functions, ect. but you’d have more people to talk to.

        Sure, it WOULD be cheaper but you’d miss out more the the community help.
        (257 users on the SDRPlay community) vs (HackRF wiki & Mailing list)

        Not to mention it’s Open

        But hey, that’s cool if you don’t need it. I’m not saying go with a Toyota Prius when you really want is Tesla or Ferrari.

        1. That is a splendid amount of information. Kudos. :)

          I’m sure that this will help many people make up their own minds about which SDR is best for them, the background info about the relative sizes of the supporting communities is very useful actually, especially if one is starting out in radio or electronics in general.

          I was amused though that you wrote “Not to mention it’s Open” closely followed by “Toyota Prius”, “Tesla” and “Ferrari”, I had to chuckle. :)

          Have a good one.

        2. Licensing depends on what country you are from, but in the U.S. there are three levels, Technition (allows access to VHF and UHF HAM radio bands, 35 question test costs about $15 takes about 10-30 mins depending on how fast you take tests and not very difficult, espicially if you have an electronics background, gets you your call sign, no morse code), general (Another $15 dollar test, this one is a bit harder, 35 questions, this lets you access some HF HAM bands, again no morse code), and Amatuer Extra (Another $15 dollar test, lets you access all HAM radio bands, again no morse code.) Morse code is not a requirement in the U.S. at any level anymore.

        3. Amateur radio licenses haven’t required mastering Morse code for years- since 2006, I think. There are three classes of license: Technician, General, and Extra, in order of the difficulty of the tests.

          Since all the questions and all of the answers to the questions are freely downloadable, anyone that can study can pass the tests.

          There’s 426 questions in the Technician class pool, and your see 35 of them on the test. There’s groups of questions in each pool– several on RF safety (you’ll get asked a few of those) some on FCC rules (you’ll get asked a selection of those) some on Ohm’s law (you get the picture.)

          It’s the same for the higher license classes. There’s a pool of 462 questions for the General exam, out of which 35 appear on any given test. The Extra pool has over 700 questions, and you’ll get 50 of them on your exam.

          More: http://www.arrl.org/question-pools

  2. Just got mine in the mail today!

    Up and running in less than 5 minutes from complete cold start (including installing HDSDR and the API etc).
    The tuning range of this thing is great, even with my crappy homebrew antenna (a 126MHz coax colinear held together with tape). Can get crystal clear national broadband radio (no surprise really), local AM broadcast at 945KHz, and can see most of the GSM bands up beyond 800,MHz then my crappy antenna becomes a wet noodle and I need to build a better one.

    I’ll do a tear down with pics tomorrow, once I’ve had a chance to play with it a bit, unless someone else beats me to it :)

    Build quality is not bad, and it seems to just work with minimal hassle (3 easy software installs, one needs you to provide your personal details and the serial number of your SDRPlay device, not crazy about that really, but meh).

    I’m off to listen to some ragchews…

  3. This product could really benefit from some mounting holes in the ABS shell enclosure. I’m going to have to buy some holes and add them myself. I can see these things being attached to car dashboards, quadcopters, the inside of large metal boxes, house walls, loft rafters, imperial cruisers…..

  4. I have built Heathkits in the 60s, 2-way system for my business from surplus equipment sold at public sale from police, fire, etc. Finally took a 10 (1 hour class per week) put on by my ham club. Mastered the Tech. questions (QRZ.com) @ 8 weeks and worked on the General the final week. Missed 2 questions (passing) so decided to try the General (covered by the same fee) & missed one question. I was 74.
    BTW, even the Extra class has no code. Gives you extra frequencies in the HF bands.

    Why did I wait 60 years? Wouldn’t if I had it to do over. Also Ham Radio Outlet (hamradio.com) is the national distributor for SdrPlay. All 12 stores sell them out as soon as they receive stock. Most of these customers are hams. Tells me it is a hot item for those who know the difference.

    73 de KF7SLM, Jim

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