![]() ![]() For best Rx performance (maximum sun noise, best G/T) the illumination of the edge of a dish is probably going to be 14-15dB less than at the center. Note that sun noise is NOT a measure of the strength of your transmitted signal. If you optimize everything (dish, feed, preamp, cables, connectors etc.) to give you the highest sun noise reading, then you have optimized your receiving system. Basically, the more sun noise you see, the more sensitive your receiving system is and the weaker the signals you will be able to detect. Sun noise can be used to establish a relative "figure of merit" for a receiving system. ![]() In the rest of this article the term "Sun Noise" is used to describe a measurement of the ratio of the power received when an antenna is pointing at the sun, to the power received with the antenna pointing at a cold part of the sky.įor more about Sun noise, see the page here on Understanding Sun Noise. So at any time the sun makes a good RF emitting source of known power and so can be used as a reference for determining receiving system perforce. While the actual power output isn't constant, it's monitored and measured by many measurements in many countries and those measurements are made public. So at any wavelength (say 23cm), you see the same amount of power radiated with vertical polatization, horizontal polarization, Right hand circular polarization, Left hand circular polatization or any other (slant, elliptical) polarization. It radiates at all wavelengths and the radiation is (generally speaking) unpolarized. The sun is a large, very hot, thermonuclear furnace that radiates energy across the electromagnetic spectrum from X-rays, through visible light and out to microwaves. ![]() Here's the summary for those who don't want to read the article:įor the best consistency between stations and between readings from the same station at different times, Sun noise (Y-factor) readings should be made my subtracting the noise power with the antenna pointing at the coldest part of the sky from the noise power with the antenna pointed at the sun. ![]()
0 Comments
Leave a Reply. |