Software Defined Retail

Your radio no longer needs a dial.  Things have progressed to a point where you can build a radio on a chip the size of a pencil point and configure the software that controls it at will. The Idea is called SDR (Software Defined Radio) and I've written about before. [LINK] It's virtue is it's flexibility: Simply modifying programs can completely change its functionality. It's amazing that when I wrote about this in 2007 SDR was still somewhat  hypothetical.

An SDR is not some idealistic unobtanium. You can now buy SDRs at retail. In other words, this is already on eBay.  Below is a list of a few products I find notable. I'm going to count down as a Top 5 just so you are tempted to scroll. If you need to get canonical rtl-sdr.com keeps a hefty list here and RadioReference.com has one here. Prices range from $10 to over $4,000!

TOP 5!

5. BitsharkExpress RX - $4,300 [LINK]
This appears to be a good product but I've down-ranked it because the price is  astronomical. It supports a tuning range between 300 MHz and 4 GHz and acutlaly uses dual A-to-D converters in a elegant design. Also it is one of the few units which mounts directly on your PC bus as a PCIe card. Thsi eliminates the USB cable many units rely on.

4.  HPSDR Hermes Transceiver Card - $895 [LINK]
This open source project came pricey, but also capable of full duplex. It could receive from 10 kHz – 55 MHz but it's A-to-D converter was only 12 bit. Most other systems are already up to 14 or 16 bit.

3. AirSpy - $200.00  [LINK]
Airspy is an advanced open-source SDR that can receive from 24 MHz to 1.8 GHz. That's not everything but that's over 1700 MHz of fun.

2. HackRF Blue - $200.00  [LINK]
This is the low-cost version of the Hack RF. Great Scott were able to achieve a lower cost by better component sourcing. Supposedly the spec its the same but I doubt that a 30% reduction in cost has zero degradation on performance. But I'd love to have the opportunity to test that.  See below

1. HackRF One Kit - $330.00 [LINK]
I really want one of these. HackRF is capable of transmitting and receiving of radio signals from 1 MHz to 6 GHz. It's software is Opensource and runs on a on a Debian/Ubuntu distro. "sudo apt-get install"hackrf" anyone?  But seriously this wins best in class. Running in an OS I'm literate in is just gravy. More here.

DRT BOX

Here is something new to be concerned about. It wasn't that long ago that tapping phone conversations required a warrant. Starting in 2001 the George W. Bush administration used new powers courtesy of the Patriot act FISA court restrictions to permit the NSA to spy directly on pretty much everyone. It's all been downhill from there.

When you're feeling dystopian, you may imagine men in suits connecting to phone lines are they route through data centers across America. To some degree you would be correct. But apparently it's also the US Department of Justice conducting mass surveillance with DRT boxes to grab your cell phone signals out of the air. It seems hard to justify, but that is what they are doing. More here. They were purchased by Boeing in December of 2008.

DRT stands for Digital Receiver Technology. That very non-specific name adorns a a wholly owned subsidiary of  Boeing. The industry jargon for this type of device is "Stingray." Simply put, a DRT BOX is software defined radio (SDR) used for wireless surveillance systems. In 1980, DRT was founded in Frederick, MD focusing on the development of  devices for communications surveillance. If you go to their website here, you'll find a couple consumer grade wireless scanners. They also have make more specialized Stingray hardware for the feds. To my amusement I found they tacitly admit this on their site "Due to the sensitive nature of our work, we are unable to publicly advertise many of our products." More here.

The Justice Department installs these DRT Boxes on board fix-wing Cessnas so they can monitor a metropolitan area. The DRT BOX is then used to emulate a cellular base station. Because cellphones are designed to connect to the strongest cell tower available, they can just overpower the weak or distant terrestrial towers. The cell phone then transmits it's registration information to the DRT BOX. More here.

The program, used by the U.S. Marshals Service, has been in use since 2007 and deployed around at least five major metropolitan areas, with a flying range that can cover most of the US population. By flying a circuit over a city they can gather information on thousands of phones in just a couple hours of flight. This cannot be used to target individuals. Because the device must emulate a carrier it gathers information on all customers of that carrier in range. Similar Stingray-like devices have existed for decades, but flying them over American cities seems to be a new development.  More here.

Software Defined Radio (SDR)

What the hell is a Software Defined Radio (SDR)? Well first of all it was hypothetical in the beginning. The idea was to build a radio with software. Obviously there are some obstacles. Even the most cutting edge attempts at this today still involve some radio hardware. The idea is that it would be able to transmit and receive signal on any frequency as needed; no hardware means... no hardware constraints! ...Except that it's still hypothetical.

Ideally this would be just signal a simple A-to-D (Analog to Digital) conversion then at the antenna a D-to-A conversion. That's not tractable however. The limitations of digital hardware prevent the reception of radio signals between 10 kHz and 2.4 GHz. That's not a small piece of RF real estate. One of the first software radios was an American military project named SpeakEasy. Of course things being what they are, there is also a competing open source project as well.

Speakeasy had Two phases:

1. A radio for the U.S. Army to operate between 2Mhz and 2Ghz. It was to operate with both VHF, FM, QAM, SSB and Combat Voice and data channels. In 1997 an operable version was demonstrated at a big brass hoe-down called Force XXI.

2. Same as above but more quickly reconfigurable for different bands and standards. 15 months into the project they had a working demo which was sent into production with a reduced 4 MHz to 400 MHz range.

So that's the excitement, they were a dream 10 years ago and now are a reality ...sort of. It's an interesting progression and I've never seen a working model myself but the GNU makes for interesting reading even if the optimistic parts read like sci-fi.