FUNcube-1 AO-73 Satellite
Date: 20150104 1809UT
- YouTube Satellite FUNcube-1 AO-73 with Airspy SDR Time Lapse.
- Date: 20150104 1809UTC
- Universal Time (UTC) in shown in the bottom left corner of the screen capture.
- Local time (PST) is shown in the spectrogram window on the left side.
- Spectrogram (also called water fall plot) shows frequency on the horizontal axis, time on the vertical axis, and signal intensity in color change.
- Spectrogram dark color is low signal intensity and red color is high signal intensity.
- Spectrogram current time is at the top of the window.
- Oldest spectrogram time is at the bottom of the window.
- TLM down link frequency: 145.935 MHz BPSK (+/- Doppler).
- Slanted colorful band on the left side to of the spectrogram.
- Transponder downlink frequency: 145.950 - 145.970 MHz USB (+/- Doppler) Mostly USB signals with some CW signals.
- Signals are from the center to half way to the right edge of the spectrogram.
- At ~ 18:15:15.6UT you can see the complete transponder band signal as a rise in the back ground noise.
- TLM beacon frequency Doppler shift is seen as a lower frequency shift through out the time lapse.
- Thin solid vertical lines in the spectrogram are local RFI.
- Notice the change in the RFI when the antennas are switched (~time 18:15:05 UT) .
- Occasional horizontal lines are strong local 2 meter signal over loading the preamp or RFI.
- Example of deep signal fading is seen at 18:15:34 UTC.
- The Airspy baseband IQ data was saved.
- The next step is to replay the baseband IQ data and decode the USB and CW signals recorded.
- Future areas of improvement is to manually track the satellite with the antenna.
- Two four elements Yagi Arrow II Portable Antenna Model 146-4 II are used.
- The antennas are positioned in the
directions to see the satellite at certain positions in the sky.
- The second four element Yagi antenna has its own coax to the receiver.
- A coax switch selects which antenna to use.
- Also, the coax switch has three positions, two for the two different antennas
and one position to a 50 ohm terminator.
- The 50 ohm terminator provides a quick check on which signals are internally generated
from the receiving system and which signals are received from the antenna system.
The above photo shows one four element Yagi antenna positioned east at 30 degrees altitude and
the second four element Yagi antenna positioned west at 30 degrees altitude.
- This configuration is used for casual monitoring (lazy mode monitoring) of the satellites.
- For this satellite pass,
- The first four element Yagi is aimed at 45 degrees azimuth and 35 degrees altitude.
- The second four element Yagi is aimed at 135 degrees azimuth and 45 degrees altitude.
- The two fixed positioned 4 element Yagi antennas are switched at satellite midpoint (~time 18:15:05 UT) across the sky.
- Toshiba Satellite P75-A
- Intel Core i7-4700MQ CPU @ 2.40 GHz
- 8 G RAM
- Microsoft Windows 8.1, 64-bit
- Data logging to Toshiba 2TB USB hard drive
Satellite Tracking Software
- GPREDICT 1.3 on Ubuntu 14.04 running on a MacBook Pro OS X 10.10.1 with Parallels Desktop 10.1.2.
© 1998-2015 David Haworth, WA9ONY