RTL-SDR is an affordable dongle that can be used as a computer based radio scanner for receiving live radio signals in your area. This particular dongle includes a R820T2 tuner, a 1 PPM temperature compensated oscillator (TCXO), SMA F connector. It features an aluminium case with passive cooling via a thermal pad. Moreover, there is a software switchable bias tee circuit, supplementary ESD protection, lower overall noise and built-in direct sampling for HF reception. This device can receive frequencies from 500 kHz to 1.7 GHz and has up to 3.2 MHz of instantaneous bandwidth (2.4 MHz stable).
Generally, the processing part of a signal is done in the hardware components themselves. Because of this, if an error happens at the hardware level, troubleshooting is very limited, and in most cases, futile to correct the problem. With software-defined radio (SDR), the RF communication is done using software, which solves the problem of signal processing limitations in the hardware. Instead of having to use mixers, filters, amplifiers, modulators, demodulators, and so on, SDR only uses an ADC and DAC along with antennas, without needing many hardware components.
The software for SDR can be used on a personal computer or an embedded system, and it offers a more flexible solution and makes it easy to fix issues. SDR is used in broadcast and amateur radio, radio astronomy, tracking airplanes and building a GSM network, and many more applications. It is a great choice for many cool projects.
Over on YouTube TechMinds has recently uploaded a video where he unboxes, constructs, and tests the kit using the free G8JCFSDR SDR software. TechMinds also notes that this SDR Shield can also transmit with 10mW of power, and that there is a tutorial included in the book that shows how to use the shield as a simple WSPR transmitter.
Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.
KrakenSDR is a five-channel, RX-only, software-defined radio (SDR) based on the RTL-SDR and designed for phase-coherent applications and experiments. Phase-coherent SDR opens the door to some very interesting applications, including radio direction finding, passive radar, and beam forming. You can also use KrakenSDR as five separate radios.
KrakenSDR is an upgraded version of the previous product, KerberosSDR. It provides a fifth receive channel, automatic phase-coherence synchronization capabilities, bias tees, a new RF design with cleaner spectrum, USB Type-C connectors, a heavy-duty enclosure, upgraded open source DAQ and DSP software, and an upgraded Android app for direction finding.
KrakenSDR makes use of five custom RTL-SDR circuits consisting of R820T2 and RTL2832U chips. The RTL-SDR is a well-known, low-cost software-defined radio (SDR), but throw five units together and using them on the same PC will not make them "phase coherent;" each one will receive signals at a slightly different phase offset from the others. This makes it difficult or impossible to achieve a high degree of precision when measuring relationships between signals that arrive at different antennas.
Next a very first version of a DAB decoder was built.SDRplay donated kindly an SDRplay device, an excellent devicewith a range from a few KHz to 2 GHz and 12 bits samples,and all software was redesigned to allow easy interfacing toother devices.
Later on, some more SDR devices already had entered the house,the Raspberry RPI 2 arrived. There is an obvious difference incomputing power between an x64 PC and an RPI 2, so restructuringof the software was required to allow the DAB decoder to run smoothly on the RPI 2 with the load reasonablybalanced over the 4 cores of the CPU.
In the section Qt-DAB and friends, DAB and DAB software is discussed.Qt-DAB is a pretty complete DAB decoder for use with some of the popular SDRdevices is discussed, and some of the other DAB related software ismentioned.
Feel free to contact me, the section Contact contains a form for that.In the endIn most of my software existing dynamic libraries(Linux) and dll's (windows) are used, e.g. libraries for audio output, fft,handling "wav" files, Reed-Solomon correction, decoding AAC and xHE-AAC,converting samplerates, etc etc, all available under a GPL-V2 or V3.All rights are gratefully acknowledged, andmy software is itself also made available under a GPL-V2 licence.
It is - obviously - nice if (some of) the software is useful, there are no guarantees, however.If the software does not fit your purpose,it might just not be the software you are looking for, read the license, that states (a.o): the SDR-J software is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.
If, however, the software seems useful and you have suggestions forimproving and/or extending it,feel free to contact me, suggestions are always welcome(although no garantees are given that they will be applied.)
The development of this - and other - SDR-J software is a hobby(see the " " repositories),a "spare time" project (being retired makes that there is some spare time).As with all hobby projects, support(such as suggestions for improvements, and additions,suggestions for modifications etc) andcontributions (such as code improvements or extensions,providing me with a yet unsupported device, etc) are welcome. 2b1af7f3a8