The Stereo (Solar TErrestrial RElations Observatory) A & B spacecraft were launched on Wednesday, October 25th, at 8:52 p.m. At the time of the first observations, the pair of spacecraft were only about 70,000 miles from Earth, and judging by the signal strength, only using the Low Gain Antenna on board the satellite. http://stereo-ssc.nascom.nasa.gov/ancillary.shtml is worth visiting - plenty of interesting information about the Stereo satellites.
Update 29/05/17 Video of reception of STEREO-A on 8.4GHz.
Update 12/02/07 Stereo-A despite peaking at only 12 degrees elevation is a very strong signal. With half the dish obscured by local clutter, the signal is still copy able in 30KHz wide FM. The carrier peaked 33dB over the noise in a 20Hz bandwidth. At the time of reception, the frequency was 8443.503MHz.
Update 10/02/07 Stereo-B is on the HGA, signals are very strong and typically can be detected with the dish many 10's of degrees of bore sight. The data as seen in the FFT below, is so strong that its perfectly audible in FM mode, regular framed data can easily be heard. The frequency Stereo-B was received on was 8446.225MHz Click on the image below to enlarge it.
(below) Zoom into 25KHz bandwidth - the framed data is clearly visible.
Update 25/01/07 Stereo-B is now transmitting data, and the sidebands can clearly be seen with a FFT receiver such as the RF-Space SDR-IQ.
(above) Stereo-A on 8443.4535MHz. The wideband images were made using an RF Space SDR-14 SDR. They show a 50KHz wide lump of spectrum, with each FFT bin being 6.8Hz in bandwidth.
Stereo-A Audio Recording:
(above) Stereo-B on 8446.165MHz.
Signal received from Stereo-B on the 10th February 2007:
The FFT Image gallery below shows some of the signals received from STEREO-A and STEREO-B over the years.