Abstract: High Frequency (HF) communication systems use radio waves at frequencies in the range of 3-30 MHz propagating in the form of skywave with the help of the ionosphere. For emergency ...
Abstract: The multi-frequency multipath observations of temporal variations in the Doppler spectra and signal amplitudes of HF radio waves reflected from the ionosphere, which accompanied ionospheric ...
It's the fourth biggest killer in the UK - but would you be aware of the signs if you - or a loved one - were having a stroke?
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