SDR – What is it and Why?
The three letters = Software Defined Radio.
What can you do with it? The sky is pretty much the limit. Think of SDR as hardware capable of being programmed as a radio utilizing software instead of electronics although the SDR hardware has electronics that give you the capabilities to use instructions to build a radio using software. You cannot accomplish one without the other. You need hardware to receive the RF signals but the software takes those RF signals from the hardware and interprets them into data that is fed into the software that can (for lack of a better term) manipulate into what you want to listen to or visualize. In my mind I think of it as the hardware sends a raw datastream or signal to the software which then interprets that data into a working radio based on what is defined in whichever software package you use. It is ultra portable for radio enthusiasts on the go and want a quick setup without hauling around big radios and power supplies etc. You still need a good antenna as you would with any radio, but at least the overall foot print is smaller. Think about using your phone or even old Android phone as a wideband radio…. Yes, you can do it… More on that below….
http://sdr.osmocom.org – SDR PCB
Background – I know the concept and usage of SDR has been around for a little while now but costs were too expensive to get my hands on the hardware and software development is not my strong suit by any means. I am more of your hardware and software applications person. Recently, I read an article in the January 2013 issue of QST magazine (Page 30) discussing a cheap way to experiement and learn about SDR using USB DVB-T television dongles designed for use in Europe. The average cost for these peices of hardware are around $25.00 on EBay. The key to finding the best one lies within the chipsets in these dongles. You should find one with the Realtek 2832U (RTL2832U) and Elonics 4000 (E4000). There are varying techinical reasons as to why the E4000 but overall you get the best performance and compatibility using this chipset. There are others out there but from all my research, the E4000 is the way to go at this point. Just go to EBay and search for RTL2832U E4000. For $25.00 versus several hundred doallars on company built advertised ones, my thought was, why not? It would give me good insight to what the buzz is all about. If it didn’t interest me, then not a huge loss.
Installation – Depending on what you are installing, this can be either very simple or extremely painful. I would start with SDR# first. It is Windows based software with windows based drivers to get your DVB-T dongle operating as an SDR quickly. After you get the concepts down, I would move on to Linux and Raspberry Pi builds. Whatever your comfort level is. I started with Windows just to get it up and running and see what it could do.
More Information here: http://sdrsharp.com/
I am currently working on an installation document of my own for several SDR packages that are server based. I will post those as time permits…..
My Current SDR Projects:
Raspberry Pi Integration – ADS-B Receiver and Plotter with Web Server for Online tracking of Aircraft in real-time. SDR Public server for Internet clients to use and control my SDR. Several other possibilities but these are my focus right now.
Trunk Tracking – using two DVB-T sticks with UniTruker to scan and listen to Public Safety Frequency hopping radio systems.
Ubuntu Public Server using QTRadio – Server / Client with Android App
Android Phone – SDR Touch is available for those wanting to turn your Android based phone or mini-PC into a full featured / functioning radio using a powered USB Hub and OTG cable. I have tested this on the HTC Inspire (rooted), Motorola Droid Bionic (unrooted), and MK802III (rooted with standard build). Works great although processor interference and “birdies present on the phone based setups but not bad enough to not make it worthwhile.
And the list goes on…. These are the main ones….
Stay tuned…. More to come…..