Joachim Köppen Kiel Dec 2022

• Radar Equation: derivation gives a step-by-step explanation of how the well-known Radar (Range) Equation is derived.
• Two Narrow Beams on the Moon When EME operations are done with large antennas and/or at high frequencies, the antenna beams may become comparable to the angular size of the Moon, or even smaller. Then the strength of the reflected signal depends on the widths of transmitting and receiving beams, as well as on their positions on the lunar disc. This tool computes and displays the illumination of the Moon's face by the transmitting antenna, the overlap of the two antenna beams, and the correction factor for EME link budget. It also computes the offset loss which occurs when the two beams are not directed to the same spot.
• Lunar reflectivity shows for any frequency how the reflectivity of the lunar disc varies from the centre to the rim. This is done by an image of the Moon and a plot of the relative reflectivity as a function of radius. The results from radar measurements are interpolated to any frequency.
• Parameters of Aperture Antennas computes the gain, half-power beam width, effective area and other parameters of circular paraboloidal antennas, as well as the antenna temperature and signal to noise ratio for a source of given radio flux and with specified system temperature.
• Measures of the noise at Sun Moon & Ground along with the empty sky gives three estimates for the system temperature. Significant differences between the values are a sign for errors in some of the measured values, which indicates that the measuring methods or/and equipment need revision or improvement. If the three values agree with each other, they very likely indicate the true noise figure of the receiving system of antenna and receiver. This 'overall' noise figure includes also how much noise from the surroundings is picked up by the antenna's side and rear lobes. It thus gives an indication for the true efficiency of the antenna. Knowing this better helps in optimizing the antenna system.
• For Scheduling Observations one needs to know when a celestial source stays above the horizon for a desired duration. This is done for the Sun, Moon, or celestial sources given by galactic or equatorial coordinates, for any geographical location, and time (UT or local sidereal time).
• Sun and Moon Position predicts for any time and location the positions in the sky of the Sun and the Moon, both in celestial and horizontal coordinates, their angular diameters, the lunar phase and radio flux.
• Aim at the Radio Moon computes and displays the radio image of the Moon in the proper orientation with respect to the local horizon, for any location, date and time, and frequency. One may also view the image as it is blurred by the finite width of the radio telescope's beam.
• Temperatures and Radio Emission of the Lunar Soil shows the variation of the temperatures in the lunar soil due to the illumination by the Sun, during a whole month and during a total lunar eclipse. It also computes the lunar radio flux at various frequencies.
• Brightness Temperature of the Moon shows the monthly variation of the temperature of the Moon predicted for various frequencies from a simple model of the heat transport in the lunar soil. The data can be ouput in the form of a text table. Measured data from professional publications obtained since 1949 are also shown.
• Lunar Radio Images shows the distribution of radio brightness on the face of the Moon predicted for any frequency and lunar phase computed with the above simple model for the heat transport in the lunar soil.
• Lunar Radio Images (Version II) shows the distribution of radio brightness on the face of the Moon predicted for any frequency and lunar phase computed with the above simple model for the heat transport in the lunar soil. In this version one may also look at the radio Moon, as it is blurred by the finite width of the beam of an radio antenna.
• Lunar Drift Scans computes and display the results of letting the radio Moon drift through the antenna beam of a radio telescope.
• Atmospheric Attenuation computes for a given radio frequency, atmospheric temperature, pressure, and humidity the attenuation by the Earth atmosphere at zenith and a given elevation angle. This is done with the approximate formulae from ITU Recommendation P.676-10 (09/2013, Appendix 2) for frequencies between 1 and 350 GHz.
• Radio sources in the sky shows the radio fluxes for well-known sources, and - given the effective antenna diameter and the system temperature - displays the antenna temperature and the expected signal to noise ratio.

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last update: Dec. 2022 J.Köppen