The frequency is 8465 MHz and for the moment don’t have ephemeris from the JPL/Horizons or spice kernels. For the moment using the ephems from GBOT getting a aprox RA and DEC and using my own tools for full tracking.
Integrating the Yutu using baudline the signals recorded during the seperation from the Chang’e 3 you can see two signal variations. At the 20:27:31 UTC during two minutes aprox the signal was more weak and scince the 20:35:40 UTC the signal was boosted. Then the separation was before of the 20:40 UTC ?
Yesterday the Chang’e3 spacecraft andt the Yutu rover was landing successfuly. I was start to track the moon since the 18:30 to the 22:30 UTC. And I was listen Yutu from the start of my window and the signal was over 15dB of SN at 1Hz of BW. The frequency of the rover is 8462.08000MHz with the moon doppler of -0.6Hz/s of aprox. The signal was easy to listen in the earphones, and sounds like a some kind of morse.
The command line to use rtlsdr with baudline was:
rtl_fm -g 44 -d0 -f$1 -s 250000 -F -U | ./baudline.static -stdin -samplerate 250000 -channels 1 -session rtlsdr1chUSB0 -basefrequency $1
Now you can listen how sounds the data stream from Yutu. A short audio record of the signal demodulated:
Another full orbit of Chang’e 3 centered ar 8470MHz with a 100KHz span. This time with locking to ground station included:
Zoom of one of the frequency lock to some tracking Ground Station:
Yesterday the Chang’e3 spacecraft finished the orbital insertion into polar orbit around the moon. The signal is strong and easy to listen in the receiver speaker. Today I get a full orbit of the probe. Every pixel are 10secs and the receiver was tuned at 8479.749200MHz
More info of Chang’e3 in Spaceflight101.
The first test to see the coherence of two rtlsdr in realtime consist in do a cross-correlation of the two dongles, the cross-correlation is a measure of similarity of two signals.
Here the result if disconnect one antenna:
After the nice videos that Juha Vierinen has shared, looks that some people is interested in use multiple rtlsdr coherent for radar applications for example. I’m starting my experiments with this setup:
My setup consist in two rtlsdr dongles with r820t tunner with the xtal removed, connected to a PTS-160 Synthsesizer tunned at 28.8 MHz and locked to 10 MHz GPS reference.
With coherence using radar mehtods, you can get cool images like:
Recently a nice activity for the Ham radio community was organizated from the JPL. The idea is that the spacecraft instruments can detect a message transmited by the Ham radio operators, here all the info. Waiting the definitive plot from the JPL here my the plot that I was record using a Rfspace SDR-14 in continuum mode, recoerding the slice from 28.0 to 28.5MHz:
Thanks to the JPL people to this kind of activities for the Amateur Radio community.
When the spaceprobes are very near to the Earth to do a flyby, the low gain (LGA)and medium gain (MGA) antennas are used. As this antennas not are in the central axis of the probe and it is rotating continuosly, you can see the rotational movement in the screenshoot:
The past agoust I was build a passive radar to detect the Perseids meteor shwoer . The most easy way is locate a very away transmiter and try to se the echoes produces by the meteors ionizacion.
“rtl_fm -f143050000 -s 250000 -p90 -F -R | baudline -stdin -samplerate 250000 -channels 2 -quadrature -record”
I recommend decimate the input and to 32 or 64 to reduce the span and increase the resolution bandwith. Some nice pictures of more meteors: