Secondary radar principle DME Transpornders are placed at ground stations, which are usually co-located with VOR beacons. Each station has a unique (within the UHF line-of-sight receiving area) receiving frequency in the UHF band between 962 and 1213 MHz. The pilot of an aircraft wishing to find its range from the station must select that…

Introduction The acronym RADAR comes from Radio Detection and Ranging. We have already seen that a radio waves can be reflected by objects, just as visible light waves can be reflected. Some of the waves will be reflected directly back towards the transmitter. A sensitive receiver tuned to the transmitted frequency can detect the reflected…

Basic principle In each plane, vertical and horizontal, a pair of antennas transmit two directional beams, directed close to either side of the ideal approach path. Each beam can be thought of as activating an electromagnet to either side of a centrally biased instrument needle. When the field strengths of the beams are equal, the…

Principle of operation The principle of VOR is bearing measurement by ‘phase comparison’. A VOR transmitter sends two separate signals which can be compared to provide the directional information. No special receiver antenna is required in the aircraft. Reference signal Station transmits an omnidirectional horizontally polarised continuous wave signal on its allocated frequency between 108.0…

Non-directional beacons The successors to the old commercial stations are the aeronautical NDBs transmitting AM signals in the upper LF and lower MF bands, between 190 kHz and 1750 kHz. The advantages of these frequencies lie in the diffraction they suffer close to the earth’s surface. Aircraft can receive surface waves if the direct waves…

Radio spectrum Frequency band designators. Abbreviation Frequencies Wavelengths VLF 3-30 kHz 100-10 km LF 30-300 kHz 10000-1000m MF 300-3000 kHz 1000-100m HF 3-30 MHz 100-10m VHF 30-300 MHz 10-1m UHF 300-3000 MHz 100-10 cm SHF 3-30 GHz 10-1 cm EHF 30-300 GHz 100-10 mm Radio waves of VHF bands and above are generally reflected by…

Image source: Google Are you finding it difficult to decide which flight school to pick for your flight training? Is it better to choose a flight school in India or Abroad? Are cadet pilot programs the way to go? I will try and explain the pros and cons and what you should look for before…