Software Defined Radio Online Course
CommTech, Eastronics and Rohde & Schwarz collaboration in delivering RF Microwave and Wireless Training Courses. A Software-Defined-Radio (SDR). Software Defined Radio attempts to place much or most of the complex signal handling involved in communications receivers and transmitters into the digital (DSP) style. In its purest form, and SDR. Introduction to DSP The BORES Signal Processing DSP course - Introduction to DSP - is free of charge on line.
REDHAWK COURSE OBJECTIVES The next course offerings by Software Defined Radio Solutions, LLC will be in REDHAWK. The course is structured to be 3 two-hour courses offered on Thursdays, July 16, 24, and 30th from 3 p.m. Due to the complexity of the REDHAWK premise, Software Defined Radio Solutions is offering two sets of tutorials. The first tutorial that is offered in July is RH1, RH2 will be offered in the near future once dates have been finalized with WinnForum.
WATCHING RADIO: this screenshot from Gqrx shows two FM stations. The central spikes are the analog stereo broadcast, while the squared-off signals on either side are digital radio transmissions. You can tune in and listen to a station by clicking on its center frequency.
The gray stripe indicates the bandwidth of the user-selected software demodulator. Because the receiver can see so much spectrum at once, you can use it to monitor activity on many channels simultaneously. For example, in Boston, where I live, there are 17 narrowband-FM police channels between 460.025 and 460.500 MHz, covering various districts, et cetera. A spike on the display shows when any of those channels is in use, and a click of the mouse has its audio playing over my speakers. Which brings us to regulatory issues.
In some countries, it’s illegal to receive any frequency you don’t have a license for, apart from public broadcast frequencies. John Deere 310 Backhoe Parts Diagram on this page. In the United States, you’re free to pick up nearly all the signals you can receive.
There are, however, important exceptions to this general rule, such as a ban on listening to cellphone frequencies, or operating equipment capable of picking up police signals while you’re in a vehicle (the latter is permitted with a ham license). Complete Taekwondo Poomsae Pdf To Jpg on this page. I soon discovered that having the dongle and TV antenna attached to my laptop is cumbersome, and besides, my home office doesn’t always get great reception.
So I spent another $35 and purchased a Model B Raspberry Pi microcontroller [see “,” Spectrum, December 2012]. The Raspberry Pi is an ARM-based, Ethernet-capable microcontroller with USB connectors that can run a number of variants of Linux. Following instructions on the, I was able to download and compile some support software to use the Pi with the dongle (connected via a powered USB hub) in about 30 minutes. In turn, I connected the Pi to the home network hub in my front room via an Ethernet cable. Using the Pi lets me place the receiver farther away from local radio sources (such as my hub’s Wi-Fi transmitter) and also allows multiple machines to access the receiver easily; the Pi acts as a centralized SDR server, thanks to a command-line utility called rtl_tcp. With the Pi running, I was able to call up Gqrx on my Wi-Fi-connected MacBook, feed it the Pi’s network address, and then control and decode signals as if the tuner were plugged directly into the laptop. (Admittedly, this represents a degree of engineering overkill when it comes to listening to a local FM station.) Now that I’ve got the basic system up and running, I’d like to extend the bottom of my receiver’s range to longer wavelength bands, such as the popular amateur 20-meter band between 14.00 and 14.35 MHz.
This will require either modifying the dongle or buying or building a frequency converter. But either approach will be pointless unless I swap my rabbit ears for a long-wavelength antenna, which is a whole other kettle of home-brew fish. For more about the author, see the Back Story, “.” This story was corrected on 27 June 2013.