@csete : The .ogg observations that I looked in at Audacity were recorded at 48000 samples per second, which should be fine for Doppler shifts at 145 MHz and 435 MHz (amateur radio bands for satellite downlinks at 2m and 70cm). Even if the downlink signal was outside the recording bandpass at the beginnings and endings of the recording, the rate of change at TCA (time of closest approach) is valuable information itself, and that should be at the middle of the recording in the middle of the spectrum at the nominal downlink frequency.
To elaborate on an earlier point, if there were three objects on a particular launch they would each get a NORAD ID and probably be named OBJECT A, OBJECT B, and OBJECT C. If we had a recording without Doppler correction, we can look at the recording and determine TCA from the uncorrected recording, then compare that to the predicted TCAs for each object.
We can also try to determine which NORAD ID corresponds to the observed downlink by applying the Doppler correction for OBJECT A to the original uncorrected recording, then applying the Doppler correction for OBJECT B to the original uncorrected recording, then applying the Doppler correction for OBJECT C to the original uncorrected recording. We can plot the spectrums for all three corrected recordings. We would expect one of them to plot as a straight line and two of them to plot as “S” curves. The straight line spectrum plot is the NORAD ID for our downlink.
But to do any of this, we need to start with an uncorrected-for-Doppler recording.
Have I made a mistake somewhere?