An SDR For The Rest Of Them

If you are a radio enthusiast it is very likely that you will own at least one software defined radio. With the entry point into the world of SDRs starting with the ultra-cheap RTL2382 based USB receiver sticks originally designed for digital TV, it’s a technology that passed long ago into the impulse purchase bracket.

If you are not a radio enthusiast, or not even a Hackaday reader, you may not have heard of SDR technology. Even the humblest up-to-date radio or TV may well contain it somewhere within its silicon, but at the user interface it will still resemble the device you would have had in the 1950s: analogue tuning, or a channel-flipper.

It is interesting to see an attempt to market a consumer device that is unashamedly an SDR, indeed that is its unique selling point. The Titus II SDR bills itself as the “World’s First Consumer Ready SDR Package”, and is based around an Android tablet mated with a 100 kHz to 2 GHz SDR tuner and a pair of speakers in a portable radio styled case. It will support all modes including digital broadcasting through software plugins, and there will be an open plugin API for developers. They are taking pre-orders, and claim that the launch price will be under $100.

It sounds like an exciting product, after all who wouldn’t want a radio with those capabilities at that price! However it leaves us wondering whether the price point is just a little too ambitious for the hardware in question, and we’ll reluctantly say we’ll believe it when we see real devices on the market. A $100 consumer price doesn’t get you much in the tablet world, and that is from high-volume Chinese manufacturing without the extra cost of the SDR hardware and the overhead of smaller volume from a niche product. There are pictures online of real prototypes at trade shows, but we’d like to see a website with fewer renders and more hard plastic.

There is another angle to this device that might interest Hackaday readers though. It should remind anyone that building one yourself is hardly a difficult task. Take an RTL2382 stick with or without the HF modification, plug it into a tablet with an OTG cable, install an app like SDR Touch, and away you go. 3D print your own case and speaker surrounds as you see fit, and post the result on

Via the SWLing Post.

42 thoughts on “An SDR For The Rest Of Them

    1. The idea is neat though, it denerdifies a lot of the popular SDR applications. Take “Outernet”, the startup broadcasting free slow simplex pseudo internet from Inmarsat. They sell specialized hardware but a radio like this would just need a software plugin and a suitable antenna and you’d have a file server. Other uses would be an out of the box ADS-B receiver for recreational pilots.

    2. What I’d really like to see is a tablet with say a dozen gpio on an exposed header, a couple full size usb ports and a common enough chip set that loading multiple flavors of Linux and android wont be a hassle. Make the case a little over-sized and I’ll add the sdr of my choice. kinda surprised we haven’t seen this from orange or banana pi yet.

        1. Only a couple more weeks till I get my CHIPs & pocketchip hopefully.. kinda but more power, I’m thinking something like the wiiU tablet for form factor, but open the back and swap a sd card for different operating systems and periphials, start with an emulator for the kids to game, swap cards and connect a omega2 to run a fantasy league at the bar with friends, throw in an sdr and an extra wifi dongle with Kali for war driving, android with an external antenna to run a drone around. sadly I just dont have the time or energy to do a kick start or startup properly.

    3. The real question is regulation. I very much doubt that their “radio” has been met with FCC approval for transmission, so at best it’s a multi-function receiver.

      That always seems to be the issue with SDR, being as we live in the age of the FCC making it mandatory to lock down even wifi router radio firmware.

  1. Nice idea but far from complete. A tablet with an RTL-SDR stick just won’t do the trick. Tuning from 0,1 to 2.200 MHz without filtering or amplification won’t give you satisfying results.
    However, this will be the future of radio communication. Superhets, Direct Conversion or whatever technique we used to apply, will now be taken over by microprocessors. Might take away the fun of building but yeah, it opens a whole new world!

    1. Especially true outside of the prime rx frequencies. Down in the air band (AM 108-137mhz) I tried an RTL-SDR w/antenna cut for 121.5 plugged into my Nokia N900 and the reception was crap even sitting waiting for my plane in the FBO and I could see the aircraft transmitting; forget hearing aircraft on approach even 3-5km away.

      1. Turn up your gain or build a better antenna, I hear aircraft from miles away using a simple discone in airband and adsb from at least 15km with my antenna in the bottom floor of my house … It’s quite sensitive, not as good as others but still good

    1. Earls problem was that he (Jon) promised a lot that would never pass FCC and at a price that wouldn’t be possible with the components he started with then dropped half the features while trying to move to cheaper parts before he apparently ran out of money to finish development and disappeared leaving a forum full of angry backers.

        1. You can watch DVB-T because the RTL chip has a dvb-t decoder built in. Data goes from the tuner directly to the decoder and only the output of the decoder goes out through the USB bus.

          When you use the RTL-SDR driver the stick goes into a ‘test mode’ where it bipasses the decoder and just dumps raw data straight from the tuner into the USB bus. That unfortunately is a bottleneck. You can’t get enough bandwidth through it to fit a whole television signal. Even if your computer has the right software and enough power to decode DVB-T or ATSC it isn’t going to happen because that much data doesn’t fit through the USB bus.

  2. Meh. First thing I noticed that it lacks the RF spectrum view. I know that one might run other apps, but showing basic radio UI just gave me a bad first impression. SDR without a spectrum view is like going blind again… Just my two cents.

    1. One of the interviews with one of their people (my memory fails me in terms of specifics, but it was easy enough to find initially) indicated that they’re doing an API for it, and that turning it into a “decent” spec an wouldn’t be difficult for someone who wished to do so. Granted, some technical skill would be required initially, but the design specifically allows for the importation of new tuning schemes, and once a chunk of good code for a Spec An is written for the Titus II, I expect distribution of such bits of code will follow quickly.

      Frankly, I think the physical design is ugly as sin, but then most modern “radios” (wifi, HD, small portable AM/FM, etc…) seem to be living in that mode right now… we’re stuck in some kind of early 80’s design timewarp (it is what many of today’s affordable designers grew up with, so there’s that…) for publicly available communications receivers. I can only hope that there will be sufficient adoption to prompt the various manufacturers to hire competent designers with better taste in the future.

      I’m also concerned (as always) about the LiON battery… there’s no claim to it being user replaceable, and while we’ve got plenty of experience with throwing away otherwise functional multi-hundred dollar devices after their battery life ceases to be acceptable, I hate to see yet another product group moving into that ecologically-disastrous space.

      It will be interesting to watch this product (and others that will shortly follow) develop. The SDR approach to radio reception puts the finer points of DSP signal processing that much more within reach of the wider hobby/hacker/enthusiast/inventor/etc… community, and that’s a very good thing.

      1. Unfortunately in the end this radio suffers from the same general problem with all general-purpose SDR implementations – unless you have a specific application in mind, most of the signals one finds will be deeply encrypted, or if not, the content is available by simpler, and higher fidelity means. I doubt if any serious ham or SWL would be all that interested in this device because better are available, more closely aligned with their needs.

      1. Yeah i use the nooelec upconverter, it works well, has some nice features and a half decent noise generator
        but getting the metal case is a must and to power it from anything but a laptop you have to add filtering to the USB power

  3. >A $100 consumer price doesn’t get you much in the tablet world, and that is from high-volume Chinese manufacturing

    reality check, it gets you 3-4 quad core 7″ tablets. You can get custom shell and branding with >1K MOQ. Order >5K and they will be happy to integrate rtlsdr in the case for you. The rest is software.

    Obviously there are challenges, you need boots on the ground to make sure you arent being screwed over and quality is at least acceptable.

    1. The key word is *consumer* price. Sure you can buy them for a lot less if you are prepared to order a quantity direct from China, but the quoted price from the SDR manufacturer is a consumer price so the article goes with a consumer price. And at the consumer level if you’re not a Hackaday reader prepared to scour AliBaba, $100 really doesn’t get you much.

      It’s also worth pointing out that a $50 and below tablet may be cheap, but it will also be awful, and probably not what you’d be happy running your SDR software on. If this product comes with that level of performance then it won’t do well at all.

      1. Quite frankly I dont follow. Whoever is running this campaign will be ordering in bulk.
        ~$25 gets you ~Pee 2 guts with 7″ screen. 4x 1GHz A7 is perfectly fine for SDR on a tablet.

    1. The problem is that you can get very low cost bulk produced android hardware, but due to patents on the codecs (MPEG LA) used on the GPU side there will be many slowly rotting blobs. Could a really smart person get most of the blobs to function with a non-android linux OS, maybe, but it would take a lot of time.

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