Roamer.com

The UK regulator, Ofcom, has published a statement on the framework for managing spectrum used by licence-exempt devices. The Spectrum Framework Review sets out Ofcom’s overall strategy for the management of spectrum through a market-based approach. In line with their duty to maximise the value and efficiency derived from the spectrum, the SFR suggests that spectrum use should be licence-exempt if the value that is expected to be derived from the spectrum under such an approach is predicted to be greater than if spectrum use were licenced. It also notes that, where interference is unlikely, licencing may present an unnecessary overhead.

The Licence-Exemption Framework Review extends the SFR by examining a number of specific (more…)

Jason Buchanan, N1SU, has announced a new digital voice mode based on WinDRM called FDMDV which claims to offer robust digital voice communication with enhanced interference rejection. The new mode requires just 1.1kHz of bandwidth and is claimed to work at signal to noise ratios as low as 3dB. It is based on 15 carriers using the 1400 MELP codec with no FEC. Fourteen 50 baud QPSK carriers with 75Hz spacing surround a central BPSK carrier at twice the power level for auto tuning and frame indication. Higher power in each carrier combined with an occupied 1.1kHz bandwidth provides improved robustness over its WinDRM and DRMDV predecessors. A poster on the WinDRM Google Group noted that audio quality was fair at an SNR lower than DRM versions.