Monday, February 22, 2010

New Amateur Radio Digital Mode - ROS

ROS is a brand-new Amateur Radio digital spread spectrum mode with the first HF contact taking place this week. -- The first contact with ROS took place on February 18, 2010, at 20:56 UTC from Vitoria in Spain to the University of Twente in the Netherlands covering a distance of 1265 Km on 7.065 MHz.

Although it's only 4 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 (similar to SSB Voice). The software has two Symbol Rates: 16 and 1 baud (the latter aimed at weak signals down to incredible -35 dbs of S/N) and can automatically synchronize any Symbol Rate.

Initial reports in Europe (See Caution Below for US based HAMs) 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.

 ... see my previous report on very robust signals -- -- (as you recall, WSPR will currently do -29db)

The HF frequencies currently used for ROS are USB 3.600, 7.053, 14.101, 28.300 MHz

To use ROS you just need your HF radio, a PC and a basic PC sound card interface, similar to PSK31 or WSPR.

The software for ROS is free and you can download it along with the User Guide and Introduction to ROS Spread Spectrum at

A Word of Caution -- Here in the United States there the FCC specifies which modes Amateurs can use and where on the bands. Some USA Amateurs are concerned that FCC regulations appears to prohibit the use of Spread Spectrum below 420 MHz and ROS is a Spread Spectrum mode. It is a very narrow Spread Spectrum same as voice, but the devil is in the details. -- 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.  In recent years the ARRL has been trying to get the FCC to re-introduce band planning by bandwidth and hopefully they will be successful.

So for now, this ham is in ROS/SWL only.

Re: Some of this information came to me via the south gate club.

1 comment:

  1. If the ARRL did in fact KILL ROS, then its time to dump the antiques from the organization and bring it into the new age of digital comms. However, since politics and old men rule the roost, we may never see it.