Inspec keywords: frequency allocation; field strength measurement; sunspots; HF radio propagation; ionospheric techniques; ionospheric electromagnetic wave propagation

Other keywords: frequency; measurement bandwidth; week; field strength threshold; extended UK models; HF; solstices; ITU; moving average sunspot number; frequency allocation; ionosphere; research; remotely controlled UK measurement system; high frequency spectral occupancy; mathematical modelling

Subjects: Ionospheric electromagnetic wave propagation; Radiowave propagation; Voltage measurement; Measurement of basic electric and magnetic variables