Radio Transmissions

Introduction | Different modulations | Image transmission | License Free Communication | The radio network "Mountain Rescue" | Listen to a radio scanner
Tetra, Acropol and Antares systems | The GSM-R (SNCF) system
Decoding Software | The radio and Internet
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Listen to radio with a radio scanner :

A scanner is a radio receiver that can automatically tune, or scan, two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing scanning when that frequency goes silent. Generally, scanners cover the non-broadcast radio bands between 30 and 950 MHz using FM and AM, although there are models that cover more of the radio spectrum and use other modulation types.
These devices offer high performance for many functions (choice of modulation, choice of the band to scan).
Scanners first became popular and widely available during CB Radio's heyday in the 1970s. The first scanners often had between four and ten channels and required a separate crystal for each frequency received. Modern programmable scanners allow hundreds or thousands of frequencies to be entered via a keypad and stored in various 'memory banks' and can scan at a rapid rate due to modern microprocessors.
There are many models, which typically sell in the United States because the use of this type of device is prohibited in France.

A wide band communication receiver like an UBC-785-XLT enables you to listen to the aircraft, to the fire brigade battling against time to save lives, listen to the police, to ham radio operators… You can get tomorrow’s news today from short wave foreign broadcast and receive classical FM band if you want to listen to music!

Active frequencies can be found by searching the internet on forums or can be discovered through the radio's search function.

 

 

 

 

 

 

 

 

If you want to monitor digital modes that use FSK or PSK (e.g. POCSAG, ERMES or MPT), you can add a jack “discriminator” output connected to the hearth of the signal demodulator.
Once added, you just have to enter the right frequency and connect your receiver to the PC soundcard to perform decoding signals from digital signals with software’s.
However, it is no longer possible to hear some conversation because these are digital and encrypted (national police, gendarmerie, GSM…)

Some geeks are developing some techniques to decode digital signals which will be operational in a few years! (I hope!)

 

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