Hey, I finally got around to doing the simple calculation of orbital velocity from this Doppler shift. The calculation is approximately 2Vo = (delta f/ f) x c where Vo is the orbital velocity (in this case, we calculate 2Vo as the sum of approach and recede velocities), delta f is the total Doppler shift of frequency, f is the reception frequency and c is the velocity of the radio waves (i.e. the velocity of light). The result comes out to 6.8 km per second. This is 89% of the accepted speed of 7.7 km per second. The calculation assumes that the ISS approaches and recedes from the receiver directly (which it doesn't, because of its altitude). However, its altitude is small compared with the total orbital tracking distance. For a simple measurement and calculation, I figure that this result is not bad! This was part of the method that Geoffrey Perry and Derek Slater G3FOZ used in the 1960s to calculate the orbits of Russian space vehicles with minimal equipment and the help of pupils at Kettering School, the so-called "Kettering Group".
@@whereswa11y As explained above, I didn't assume any height, only that the altitude is small compared with the tracking distance. This is the main error in the speed calculation. I was keeping it simple!
Hey, I finally got around to doing the simple calculation of orbital velocity from this Doppler shift.
The calculation is approximately 2Vo = (delta f/ f) x c where Vo is the orbital velocity (in this case, we calculate 2Vo as the sum of approach and recede velocities), delta f is the total Doppler shift of frequency, f is the reception frequency and c is the velocity of the radio waves (i.e. the velocity of light). The result comes out to 6.8 km per second. This is 89% of the accepted speed of 7.7 km per second. The calculation assumes that the ISS approaches and recedes from the receiver directly (which it doesn't, because of its altitude). However, its altitude is small compared with the total orbital tracking distance. For a simple measurement and calculation, I figure that this result is not bad!
This was part of the method that Geoffrey Perry and Derek Slater G3FOZ used in the 1960s to calculate the orbits of Russian space vehicles with minimal equipment and the help of pupils at Kettering School, the so-called "Kettering Group".
6.8? NICE, 7.6 would have be magic.
Well done.
what height did you use for the ISS?
@@whereswa11y As explained above, I didn't assume any height, only that the altitude is small compared with the tracking distance. This is the main error in the speed calculation. I was keeping it simple!