Microwave Case Study

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Q1a A. Skywave 2 – 3 Mhz if prior to sunrise 3 – 6 Mhz if after sunrise B. Skywave 5 – 10 Mhz C. Groundwave/Skywave 2 – 4 Mhz full range prior to and after sunset although would bias towards 4Mhz before sunset and towards 2Mhz after sunset. Would also utilise higher power levels whilst using groundwave, although for a voice circuit skywave would easily be achieved utilising only 40 watts of power. D. Skywave 2 – 4 Mhz E. Groundwave/Skywave 2 – 4 Mhz full range prior to and after sunrise although would bias towards 2Mhz before sunrise and towards 4Mhz after sunrise. Would also utilise higher power levels whilst using groundwave, although for a voice circuit skywave would easily be achieved utilising only 40 watts of…show more content…
VLF is far better for a submarine, operationally, if only able to come close to the surface without actually surfacing. The transmission of ELF/VLF requires antennas of great lengths, therefore impossible to install on a submarine. If a submarine is required to transmit, it must deploy an aerial to the ocean surface, or actually surface to utilise one of its fixed asset aerials for communication using HF/UHF or VHF). Q2b The use of “burst transmissions” is usually conducted using HF (3-30MHz)/VHF (30-300MHz)/UHF (300-3000MHz)/SHF (3-30GHz), and involves either the deployment of a buoyant trailed wire antenna or the submarine actually having to come to the surface to utilise on of its extendable whip antenna or other fixed antenna. The actual transmission, usually contains a massive amount of data but with a very short transmission time. Due to the larger than normal amount of data the transmission is of a greater bandwidth, therefore more susceptible to scanning and eventually Direction Finding, to alleviate this, frequency hopping is used. Q3 The difficulties that would be encountered with an aircraft approaching the UK. Initially, the obvious one, with the aircraft closing the UK, it would constantly reduce the distance between the aircraft and the Transmit/Receive aerials, which would need a reductions in frequency the closer the aircraft got. This would not be a problem
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