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#Mon Aug 09 12:01:41 CEST 2010
Text__B8VU0KOdEd-WfYQ0GneCwQ_title=Function Principle of a Twin Horn Receiver
Text__B8VU0KOdEd-WfYQ0GneCwQ_text=<p>The <i>Twin Horn Receiver</i> displayed in the exhibition is the 15 Giga Hertz one. The instrument is an example of a <i>Dicke Radiometer</i>. </p><p>Radiation coming from the cosmos is reflected into the horns by the plane mirror in front of them.  There is an angle of approximately 5 degrees between the axis of the two horns. The instrument measures the difference between the signal arriving from the two horns.</p><p>If radiation was uniform, there would be no difference between the two signals. However, a non-zero difference is a measure for a fluctuation if bachground radiation, or <i>anisotropy</i>.</p>