Noise Floor for HF and VHF Bands in the UK are Rising

According to a report by the High Frequency manager of the Radio Society of Great Britain (RSGB), the noise floor continues to rise on the HF bands in the UK. The threat of PLT [power line telecommunications] for the last 10 years has largely been superseded by noisy electronics, in particular switch-mode power supplies in lighting and solar PV [photovoltaic] arrays, and broadband Internet delivery systems such as VDSL2. A further potential threat from wireless power transfer systems (WPT) is being closely monitored at the ITU [International Telecommunication Union].

Several countries have started implementing the new 5 MHz band agreed to at the World Radiocommunication Conference 2015 (WRC-15). These countries will continue to work towards the goal of achieving a harmonized band plan at 5 MHz across all regions. The operation on the new 15 kHz band segment by and large has been orderly. The main problems continue to be out-of-band operation by some operators. The RSGB is working with telecommunications regulator Ofcom and the Ministry of Defence to secure access to the new band next year - while retaining access to the existing 5 MHz channel frequencies.

In his VHF/UHF Spectrum Forum report, VHF Manager John Regnault, G4SWX, pointed out that, earlier this year, Ofcom revised the noise-floor criteria used to calculate coverage areas for certain business radio users. The change from the previous figure of –104 dBm to –92 dBm - recognizes the increase in man-made noise in this part of the spectrum. The change resulted after surveys and pressure from business users of this part of the spectrum.

Regnault said this should come as no surprise to users of 6 meters and 4 meters [70 MHz] in the UK, who already understand that the noise floor on those bands is primarily from man-made sources. Unfortunately, this degradation of the RF spectrum is unlikely to feed through into EMC [electromagnetic compatibility] standards that are sadly very poor above 30 MHz.

Click here to read the report.