R2223 mars express
Data taken 08apr06. I did
simple processing of file mex.002. The start of the file had the
cal. The middle of file had the antenna looking at mars.
dynamic spectra image. 0 to 50 khz shown (.gif)
1K xforms (250e3/1024 = 244 hz resolution)
average 1000 spectra (4.1 secs)
Ended up with 500 averaged spectra
No doppler correction, bandpass calibration, or cal scaling. Image is
in power. I've stretched it to pull out the signal.
1 (SC) dynamic spectra image. 0 to 50 khz shown (.gif)
The planet is the echo at 20 khz.
The orbiter transmitter is at 31 khz.
I then averaged 10 minutes worth of spectra where the planet
was the strongest [utc 21.84 to 22.01]. An 8th order polynomial was fit
to +/- 50Khz (excluding outliers) and then the average was divided by
fit to put the spectra in Tsys units.
minute average spectra (utc 21.84 to 22.01) (.ps) (.pdf):
The white trace is the OC, the red is SC. There was some doppler drift
over the 10 minutes. The SC/OC ratio for the planet echo is about 19%.
Some of the SC signal will be coming from polarization impurities of
Tx and Rx. This can be estimated from the SC value seen at the
frequency (31khz). The Ratio of SC/OC for the planet is much
than the SC/OC for the transmit frequency so there must be some "real"
SC coming off of the the planet.