RTL SDR is generally completed by two chips, one is called a tuner, and the other is a demodulator. The function of tuner is to amplify, downconvert, filter, etc. the signal of the specified frequency and bandwidth, and send it to the demodulator chip. The demodulator chip first digitizes the signal by A / D sampling, and then performs corresponding arithmetic processing according to the TV system to be received, and outputs information such as video stream, sound, and data broadcasted by the TV station. Because the working frequencies of various systems are different, in order to make the chip manufacturer able to put it into production many times and use it for a long time, they will design the tuner chip to cover a wide frequency band and set different receiving bandwidths. Then, according to user needs and government radio regulations, certain frequency bands are turned on in different products, and certain frequency bands are disabled.
If the tuner is cracked, then there is a way to enable the receiving capability of all its frequency bands, including receiving aircraft signals at 1090MHz. The demodulator in the TV stick cannot of course demodulate the signal transmitted by the aircraft, but the demodulator performs A / D sampling on the signal sent by the tuner. This sampling function is necessary to demodulate any signal, and of course it can also be used to Demodulate the signals emitted by the aircraft. By cracking the RTL SDR driver, the signal of the tuner is digitized by the stripper for A / D sampling and then sent directly to the computer through the USB interface, so that we can process the original tuner signal sampling on the computer, that is, use the computer software to demodulate Tasks. The above method of demodulating communication signals using computer software is the so-called “Software Defined Radio” (SDR). In fact, the research and development of software radio technology has a history of several decades, originally originated from the multi-standard radio project of the US military. At present, software radio technology is widely used in the mobile communication systems that we use daily. For example, the signal processing in base stations is largely completed by programmable FPGA and DSP. Tuning method (except for a few modules with a large amount of computation and high real-time requirements, such as turbo decoders, spread-spectrum correlators, etc., these modules often embed some highly customized “hard” cores in the baseband processor to implement) Later, these foreigners developed a lot of USB peripherals based on this chip, which are specially used to play SDR, collectively called: RTL-SDR DONGLES.
- Supports Digital terrestrial video and radio program recording (records digital terrestrial TV on PC or Laptop).
- Included Input Terrestrial Antenna will offer stable TV signal.
- Supports Real Time digital video recording and broadcasting.
- Supports Watching DVB-T digital TV and listen to DAB and FM radio.
- Full DVB-T bandwidth reception (at 6 / 7 / 8MHz)
- Supports Still image snapshots and PIP (Picture in picture) function.
- Can Schedule recording using the built-in Scheduler and Time-shifting function
- Digital TV recording and playback as DVD quality
- Support both MPEG-2, MPEG-4(H.264) encoding
- Support multi-picture display
- Support EPG (Electronic Program Guide);
- Support Teletext
- Support Microsoft BDA drivers
- Supports Remote control
- Support Systems: Windows 2000/XP/Vista/WIN7/WIN8
- System Requirements: CPU: Pentium IV 1.8 GHz or above
- Operation System: Windows2000 SP4, Windows XP SP2/W7/W8 (Desktop, Notebook, etc)
- DirectX9.0c or above
- Memory: 128MB
- 500M of available hard disk space or above
- CD-ROM Drive
- USB2.0 Interface.
What is the difference between the RTL dongles
- RTL2832U FC0013B 22 – 1100 MHz (Frequency and antenna connector)
- RTL2832U R820T 24 – 1766 MHz (frequency and antenna connector)
- This RTL2832U R820T2 25 – 1766 MHz (frequency antenna connector better noise floor about 6dB lower, slightly better sensitivity, Sample Rate up to 10MHz (But USB will limit you throwput to about 3.2Mhz)
The T2 has different intermediate frequency filters allowing for wider IF bandwidths and apparently slightly better sensitivity (a few dB lower noise floor?). For rtl-sdr dongles this difference in IF filter bandwidth usually doesn’t matter much since all of them are larger than the RTL2832U’s debug/SDR mode bandwidth of ~3 MHz But there are certain situations where a larger tuner bandwidth is advantageous: such as when using Jowett’s HF tuning mod.
The DVB-T dongles is based on the Realtek RTL2832U and can be used as a cheap SDR, since the chip allows transferring the raw I/Q samples to the host, which is officially used for DAB/DAB+/FM demodulation. The possibility of this has been discovered by Eric Fry (History and Discovery of RTLSDR). (With the necessary software and antenna you could listen to the following frequencies 48.25-863.25 Mhz.
Officially the RTL dongle documentation only specify the frequency range “48.25-863.25 MHz” but the one’s I have tested do work from about 24MHz to 1766MHz with a dead spot just above 1.2Ghz
To see this RTL dongle in action go to this webSDR at http://zr6aic.giga.co.za:8901 the 2m band is using RTL dongle.
It has an MCX antenna connector, which is not really popular so you will need adapter if you want to connect to external antenna.
Windows SDR# software is available here
This image show the difference in sensitivity and filter.
Linux Quisk software.
Quisk is available here
Click on Youtube video below to see the RTL dongle in action
Installation instructions here.
DVB-T + DAB + FM RTL2832U + R820T2 Support SDR Tuner Receiver Mini Portable Digital
|Shipment Weight||0.055 kg|
|Shipment Dimensions||18 × 18 × 6 cm|
- Windows SDR# Software
- Linux Quisk software.
- Installation Instructions
- Creating a 2m Fm Repeater with a Raspberry Pi (B) and a RTL dongle.
- How to install Gqrx SDR software on Linux using your RTL dongle or Softrock receivers.
- SDR# connecting to Raspberry Pi
1 x Software Radio RTL2832U + R820T2 RTL-SDR ADS-B DVB-T DAB SDR Receiver