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www.southgatearc.org
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Amateur Radio data mode ROS proving popularAlthough it's only 3 days since the first HF contact with the new Amateur Radio data mode ROS, it's proving popular with plenty of activity on 14.101 MHz. ROS is a digital spread spectrum mode but with a narrow total occupied bandwidth of about 2.2 kHz. The software has two Symbol Rates: 16 and 1 baud (the latter aimed at weak signals down to -35 dbs of S/N) and can automatically synchronize any Symbol Rate. Initial reports talk of it being able to copy signals so weak that they don't show up on the Waterfall and there are early indications that it is several dB better than Olivia. However, HF with its Fading, Doppler, Multi-Path and Interference is a hazardous environment for digital signals and only time will tell how well it performs against the other modes. One issue the mode has thrown up is the restrictive Amateur Radio License conditions in the USA. Here in the UK we are used to the "Technology Neutral" approach adopted by our regulator Ofcom. This permits us to devise and use any mode we like with any bandwidth as long as the transmission fits within the Amateur band. The United States is not so fortunate, there the FCC specifies which modes Amateurs can use and where. Some Amateurs in the States are concerned that FCC regulations appears to prohibit the use of Spread Spectrum below 420 MHz and ROS is a Spread Spectrum mode. To be fair to the FCC they did try back in 1977 to change from a mode based band plan to one based on bandwidth. At the time the ARRL opposed the change and was successful in defeating it, as a result the development of digital modes was crippled for decades to follow. You can download ROS from Soundcard Interfacing New amateur radio digital mode - ROS Southgate 2005 - ARRL lobbies for regulation by bandwidth
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