/sci/ - Science & Math

on the off-chance someone knows
I'm working a problem involving path losses for geostationary satellite transmission. It's just frequency-dependent inverse square stuff, simple enough
[math]L_p = (\frac{1}{4000pi\frac{R}{\lambda}})^2[/math]
where R is taken to b 38,500, and the uplink (earth-to-satellite) frequency is 14.15 GHz
this yields -207.17 dB for the loss, which is correct

Now for the downlink (satellite-to-earth), the frequency is 11.45 GHz. Evidently there is a multiplicative term now,
[math]L_p = (\frac{1}{4000pi\frac{R}{\lambda}})^2 \cdot (\frac{f_{up}}{f_{down}})^2[/math]
which changes the path loss from -207.17 to -205.33 dB. This multiplicative frequency-scaling term is never mentioned in either the textbook or lecture notes, and I'm at a complete loss as to why it's there given that (save for the frequency), the path loss feels like it should be symmetric for identical distances

does anyone have any idea what this term is

on the off-chance someone knows
I'm working a problem involving path losses for geostationary satellite transmission. It's just frequency-dependent inverse square stuff, simple enough
[math]L_p = (\frac{1}{4000pi\frac{R}{\lambda}})^2[/math]
where R is taken to b 38,500, and the uplink (earth-to-satellite) frequency is 14.15 GHz
this yields -207.17 dB for the loss, which is correct

Now for the downlink (satellite-to-earth), the frequency is 11.45 GHz. Evidently there is a multiplicative term now,
[math]L_p = (\frac{1}{4000pi\frac{R}{\lambda}})^2\cdot (\frac{f_{up}}{f_{down})^2[/math]
which changes the path loss from -207.17 to -205.33 dB. This multiplicative frequency-scaling term is never mentioned in either the textbook or lecture notes, and I'm at a complete loss as to why it's there given that (save for the frequency), the path loss feels like it should be symmetric for identical distances

does anyone have any idea what this term is