SOLVE SKYDIP

Skydips are special scans where the antenna is moved in elevation at a fixed azimuth. For each elevation (regularly spaced in airmass), total power from the sky, $P_{sky}$, and the hot load, $P_{hot}$, are recorded. Since one knows the effective temperature of the hot load, $T_{hot}$, one can derive either the receiver temperature, $T_{rec}$, or the forward efficiency ,$\eta_f$, via:

$$(T_{hot}+T_{rec})\times \frac{P_{sky}}{P_{hot}} - T_{rec} = \eta_f \times Airmass \times \tau_{zenith} + (1-\eta_f)\times T_{ground}$$ (22)