A Globally Standardized International Broadcaster Text Format

That Can Be Decoded by Almost Any Shortwave or Longwave Receiver with a Mobile Phone


Abstract

International Broadcasters need to be able to disseminate data, namely in website or NAVTEX like form to listeners that may have no wireline internet connection -- and do so over thousands of kilometers. 

There are hundreds of variations of Radioteletype (aka RTTY) that have evolved since the 1930s. Some of these RTTY transmission modes are very robust, and some are somewhat fragile. Many (but not all) RTTY modes have issues with channel splatter (out of channel harmonics) and equally importantly Error Correction.  

In order to convey the amount of text data (and highly compressed image data) that an international broadcaster requires, 95% of the RTTY modes have to be ruled out for use.

The transmission waveform has to be very energy efficient and hopefully less than 100% Duty Cycle. Lower Duty Cycle waveforms are less taxing on some of the transmitters deplorable for this use.

Primarily only these transmission modes are suitable (possibly with modification)

are about the only reasonably viable transmission types.


Base Specification

The base transmission format should be MT63 @ 2khz @ Short Interleave

Transmitted characters below 127

Containers : XML should be used, but it should be a compressed kind specifically for HF & LW.

The Base Coding for the container should be XML-ASCII6, or its close relative used by the maritime sector XML-AIS.

The Base Coding format for the text data should be UTF8.

Transmitter characters above 128

The Base Coding for Error Correction, Random Number Ranging Sequences and




















Summary

Containers

Text & HTML structures <{XML6{UTF8}}>

Control Data

<{Checksum_hashsum_mode_Range00}>

<{Checksum_hashsum_Range01}>

<{Transmitter_State_Range02}>

<{Time_signal_Range03>


References

Radioteletype (RTTY)

Data Formats

International Broadcasters as Data Broadcasters



Initial Idea
Document Created
Last Modified
Version
Status

15 December 2014
21 May 2014
21 September 2015
0.22
Minor fixes, updates