Making Software Defined Radio Portable

While most smartphones can receive at least some radio, transmitting radio signals is an entirely different matter. But, if you have an Android phone and a few antennas (and a ham radio license) it turns out that it is possible to get a respectable software-defined radio on your handset.

[Adrian] set this up to be fully portable as well, so he is running both the transceiver and the Android phone from a rechargeable battery bank. The transceiver is also an interesting miniaturized version of the LimeSDR, the Lime SDR Mini, a crowdfunded Open Source radio platform intended for applications where space is at a premium. It operates on the 10 MHz to 3.5 GHz bands, has two channels, and has a decent price tag too at under $100.

For someone looking for an SDR project or who needs something very portable and self-contained, this could be a great option. The code, firmware, and board layout files are all also open source, which is always a great feature. If you’re new to SDR though, there’s a classic project that will get you off the ground for even less effort.

20 thoughts on “Making Software Defined Radio Portable

        1. You are not going to see that happen until the price of the LMS7001M (1@$109 on digikey) drops by at least 80%. Also the 8 layer PCB (ref: https://github.com/myriadrf/LimeSDR-Mini/blob/master/hardware/1v0/Project%20Outputs%20for%20LimeSDR_Mini_1v0/Gerber/LimeSDR_Mini_1v0_Rounded_panel.EXTREP ) is not going to be as cheap to manufacture. For comparison the LimeSDR (original) uses a 12 layer PCB, the HackRF uses a 4 layer PCB, and most RTL-SDR’s with a R820T tuner use a 2 layer PCB.

          Maybe a cheaper board (300MHz to 3.8GHz) could be made with the LMS6002M chip (250@~$25 on digikey) but you would still have a difficult time unless you cutout all re-sellers, who typically would require at least a 30% profit margin. And you would need to include something to cover below 300MHz, but that solution would need to be extremely cheap to be competitive with the limesdr mini.

      1. What cheaper SDR? Are there any?
        This is a TRANSCEIVER, not a receiver. I think you’re thinking of the cheap USB receiver dongles which have worked fine with several available SDR apps for some time now.
        If there are cheaper SDR tranceivers, I don’t think they are portable ones. I think this is as cheap as portable SDR gets.

        1. Right, that was noted on this older HaD article… like $300 to $1000+ range was cheap?
          https://hackaday.com/2013/08/23/a-comparison-of-hacker-friendly-sdrs/

          Off the top of my head, thinking the HackRf the closest???

          Ham shield comes to mind though doesn’t cover the spectrum range.

          I was wondering if Picoscope or Discovery 2 has been hacked out or coupled with other kit to have more transceiver functions like Red Pitaya? Yep, back up to $300 going price for starters. The scope, generator, modulator idea design may be an interesting future project to show how to make a transceiver from say desk or rack mount equipment.

  1. NM on my previous comment HaD, I’m a bit out of it at the moment it seems.
    Confusing the old link with the present article, sigh, I feel like some sort of president or congressperson.

  2. I’d like to see this in a case with the batteries and a spot for the limesdr mini integrated s.t you can just plug in a usb cord to a phone or a tablet and go. At least, that’s what I’d like to do once I get mine.

  3. Is there something with the OTG cables for android devices regarding powering the device and charging the phone? Seems I read somewhere the phone doesn’t charge and only the device is powered with certain OTG cables with the additional USB battery/adapter.

    1. It’s not possible through standard OTG. Phones with custom connectors may be able to manage it; the micro-B connector on Samsung phones is actually a custom job with extra hidden pins that lets you do it with the right dongle.

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