opfjs.blogg.se - Tetrapol radio

It is used in many parts of the world, but not in the USA.There are several options for radio network owners and operators to introduce broadband services. TETRA is a type of digital voice and trunked radio communications system that stands for “Terrestrial Trunked Radio”. Software is written in C++ and licensed under GPLv3 and use few external softwares with compatible licensing. The ETSI codec is also provided so unencrypted speech can be played. A recorder, which read Json stack output and reorder speech frames into separate files.A decoder, which is the actual TETRA stack reading bits and transforming it to Json text.A physical layer transforming PI/4 DQPSK rf signal to bits (RF frontend is NESDR at 2MBPS).

The decoder implements a soft synchronizer allowing missing frames (50 bursts) before loosing synchronization.

Reassociate speech frames with a simple method based on associated caller id and usage marker (save messages transmitted simultaneously in separated files).

Transmit downlink informations (including speech frames) in Json plain text format to be recorded or analyzed by an external program.

Stays as close as possible to TETRA specification layers defined in ETSI EN 300 392-2 v3.4.1 (2010-08).

is inspired by a lot of existing stuff (see 'Previous work' in the project page) but started from scratch with those following ideas: TETRA-Kit is an extensible open source TETRA downlink decoder for Linux that makes use of GNU Radio as the first stage, so it should be compatible with any SDR supported by GNU Radio, including the RTL-SDR. Thank you to Larry for submitting information about his latest project called TETRA-Kit. JTETRA-Kit: A New Open Source TETRA Decoder

ExtIO with Decimation & Tuner Bandwidth Controls.

Manual gain controls and decimation driver.

Measuring Traffic Volumes with Passive Radar.

SignalsEverywhere Direction Finding Tutorial.

Measuring Filter Characteristics & VSWR.

Performing Replay Attacks with RTL-SDR and RpiTX.

QRP (FT8, JT9, WSPR etc) Monitoring Station.

Decoding 433 MHz ISM Band Weather Stations.

GOES 16/17 and GK-2A Weather Satellite Tutorial.