ROS network on 27635 kHz

ROS software window

The recent Sporadic E (Es) openning in Europe, very prominent on 50 MHz, allowed also extensive freeband digital operations on 11 m, 27635 kHz. The freebanders use exclusively the ROS protocol, which is designed and implemented by Jose Alberto Nieto Ros EA5HVK. They use callsigns like 13RF441 or 14OCF77, where the first numerical digits indicate the country of the stations, according to the Alfa-Tango Prefix and divisional QSL list. The stations follow procedures very similar to ham radio, especially like the ones used on PSK31 frequencies.

Freebander ROS activity on PSK Reporter

The freebander ROS activity is also supported by the on-line real time map logger PSK reporter, most operators and some listeners upload regular reports.

ROS is a very efficient MFSK protocol, suitable for low S/N ratios, which is also used in the amateur radio bands, especially on 14103, 28140 and 50245 kHz.  

The current version of the program is 7.4.0 and it is available for free on https://rosmodem.wordpress.com/ along with OPERA beacon software, also developed by EA5HVK. Instructions for system and software setup by G0HDI are available on the Welcome to GoHDI's ROS mode page. Technical information about the ROS protocol is described in the SIGID Wiki. Genenally setup is very easy with automatic tranceiver discovery and identification over serial port CAT links. It allows the definition of multiple system profiles, in order to support multiple radios etc, similarly to WSJT-X.