Radioastronomy and interferometer

 Full 24h observation data, latest recortding on top (for full list of files visit this site)

29 Jun 2014 12-12 UTC Download elev. 34 New cables, shorter file from 21pm, TSYS < 70K
30 Jun 2014 12-12 UTC Download elev. 34 New preamp, TSYS < 70K
29 Jun 2014 12-12 UTC Download elev. 34 New preamp, TSYS < 70K
28 Jun 2014 12-12 UTC Download elev. 34, NF measurements at abt 20h and 10h, preamp change at 10 utc
27 Jun 2014 12-12 UTC Download elev. 34
26 Jun 2014 12-12 UTC Download elev. 34
25 Jun 2014 12-12 UTC Download elev. 34
24 Jun 2014 12-12 UTC Download elev. 34
23 Jun 2014 12-12 UTC Download elev. 34
22 Jun 2014 12-12 UTC Download elev. 34
21 Jun 2014 12-12 UTC Download elev. 34
20. Jun 2014 12-12 UTC Download elev. 34
19. Jun 2014 12-12 UTC Download elev. 34
18. Jun 2014 12-12 UTC Download elev. 34
17. Jun 2014 12-12 UTC Downloadnew elev. 34
6. Jun 2014 12-12 UTC no- data -Download elev. 37
5. Jun 2014 12-12 UTC Download elev. 37
1/2. Jun 2014 12-12 UTC Download elev. 37
30/31. May 2014 12-12 UTC Download elev. 37
26/27. May 2014 12-12 UTC Downloadelev. 37
25/26. May 2014 12-12 UTC Download NEW elev. 37, solar bursts 18:16 and 19:10
24/25. May 2014 12-12 UTC Download NEW elev. 37
16/17. May 2014 12-12 UTC Download elev. 31
15/16. May 2014 12-12 UTC Download elev. 31
14/15. May 2014 12-12 UTC Download elev. 31
13/14. May 2014 12-12 UTC Download elev. 31
12/13. May 2014 12-12 UTC Download elev. 31
11/12. May 2014 12-12 UTC Download elev. 31
10/11. May 2014 12-12 UTC Download elev. 31
9/10. May 2014 12-12 UTC Download elev. 31
8/9. May 2014 12-12 UTC Download elev. 31
7/8. May 2014 12-12 UTC Download elev. 31
6/7. May 2014 12-12 UTC Download elev. 31
5/6. May 2014 12-12 UTC Download elev. 31
1/2. May 2014 12-12 UTC Download elev. 31
30 apr./1. May 2014 12-12 UTC Download new elev. 31, antenna correction at 22:00 utc
29/30. april 2014 15-12 UTC Downloadelevation. 31, antennas missalligned
28/29. april 2014 15-12 UTC DownloadNew declination, ground noise
27/28. april 2014 15-12 UTC DownloadNew baseline, antennas not perfectly alligned
26/27. april 2014 12-12 UTC Download
25/26. april 2014 12-12 UTC Download
24/25. april 2014 12-12 UTC Download
23/24. april 2014 12-12 UTC Download
22/23. april 2014 12-12 UTC Download
21/22. april 2014 12-12 UTC Download rainy in 1.st part
20/21. april 2014 12-12 UTC Download missing 4 minutes, rain 2.nd part 21:51-21:55
18. april 2014 11-11 UTC Download
17. april 2014 11-11 UTC Download change to 11h-11h SUN at bgn/end
14. april 2014 00-00 UTC Download
12. april 2014 00-00 UTC Download
11. april 2014 00-00 UTC Download
10. april 2014 00-00 UTC Download
9. april 2014 00-00 UTC Download
8. april 2014 00-00 UTC Download
7. april 2014 00-00 UTC Download poor sensibility, antenna missallignment
6. april 2014 00-00 UTC Download poor sensibility, antenna missallignment
5. april 2014 00-00 UTC Download note file not complete, missing few hours
4. april 2014 00-00 UTC Download
3. april 2014 00-00 UTC Download
2. april 2014 00-00 UTC Download
1. april 2014 00-00 UTC Download
31. march 2014 00-00 UTC Download note: improved pointing, auto new file at 00
26-27. march 2014 Download
25-26. march 2014 Download
24-25. march 2014 Download
23-24. march 2014 Download
22-23. march 2014 Download note:rain, thunderstorm at 14:55
21-22. march 2014 Download
20-21. march 2014, Spring Equinox Download
19-20. march 2014 Download
18-19. march 2014 Download

SIDI, Simple digital interferometer for amateur radioastronomy

Sidi Article on EUCARA 2014

for amateur astronomers, simlicity, cost and easy building is essential. Marko - S57UUU designed this device to participate the ERAC (European Radio Astronomy Club)  project aiming to build an amateur VLBI system called ALLBIN. First incarnation of sidi was in 2007, built with TV tuners and connected to the pc on parallel port. Later, USB2 interface was built and bandwidth increased to more than 10MHz. More on project can be found on Marko's page.

On satturday, 8th of March 2014 Marko finished his SIDI 1.2 and has brought it to my place for real-life test, where we set up the antennas to try the transit interferometry.

We used natural slope on the East side, where we hung the antenna to the road fence, the other is on the wheels on the WW2 German Flak.

First attempts of recording the Orion radio sources failed, detailed inspection of the hardware in the following days has shown that transport and inactivity has caused some wires to get loose ;) Marko wrote a bunch of useful software, but we were still not able to detect if both channels are working. For the next version, a signal detector and simple spectrum analyzer for both tuners would be a good idea.

On march 18. 2014 in the evening i managed to fix loose wires in the SIDI, with promising first results. With 30m baseline and two SBFA s53mv 23cm antennas, pointing to south on 1575 GPS frequency, first fringes showed up. After this, the 3m parabolic dishes, pointing exactly to south and 40 deg. of elevation the fringes on GPS band became smooth and clear.

 

First GPS fringe, 30m baseline, 1575 MHz

25m baseline, 2 x 50cm SBFA antenna

 

GPS fringes, 3m dish 42m baseline

45m baseline, 2 x 3m parabolic antenna

 

Encouraged by successful start, i left SIDI running and recording on 1420 MHz over the night. A nice surprise came in the morning, when by coincidence very clear fringes appeared, and stellarium told me, antennas are pointing towards Aquila constellation (somewhere near 18h50 min,  -5 deg).

 

First fringes from the faint radio source (18h49min, -5deg) near Aquila constellation.

After checking with VizieR site, this is most probably the GM44  at 18 47 38.02    -01 55 32.7 (RA2000, DE2000).

Next day, Orion nebula was recorded with integration of 16M samples. Arrival, maximum and decline are shown in the screenshots.

Orion arrival

More images in galery

In the next days, we started to list the sources recorded, list can be found Radio sources recorded with SIDI.

 

To do:

- Time scale on graph, slider in time axis

- Radio source power measurement detector

 

 

 

 

I have some nice gadgets handy, such as R820T dongle for RTL-SDR, nice WW2 gun-mount 3m dish, s53mv preamp and a S57UUU paprika-feed. Let's try to do some radio-astronomy experiments, with this hardware it should be possible to find the 21cm hydrogen line first.

I had some trouble finding software for spectrum display with long averageing window, or better to say something that would run with my version of gnuradio and on Ubuntu Linux 12.04. The simple_ra only runs with gnuradio 3.6 and i was not able to compile it on my latest version (3.7).

Marko S57UUU sugested to write my own software (it's obvious, since he got  ERAC FFT-DSP award), so i started writing code and while searching for some copy/paste stuff i found an interesting project  - rtlizer software by OZ9AEC developed for a beaglebone. I tried to run and compile it on my system and it worked immediately, it is very clean and simple, so i only added averageing and gain control.

I have put the sources here lana.hamradio.si/~s57ra/images/astronomy/software/rtlizer.tar.gz

Just compile it (./compile) and run (./run.sh).

Depending on GTK you have on the system, you might have to un/comment the line in compile script. I am using ubuntu 12.04 and i had to install gtk-devel package:

sudo apt-get install libgtk-3-dev

Run the spectrum analyzer with window size parameters as:
rtlizer 640x360+0+0   

commands while running:
F1 - print various data about receiver in terminal window
F2 - toggle AGC (auto/manual)
F3 - decrease gain
F4 - increase gain
TAB - increase averageing
SHIFTTAB - decrease averageing
LEFT - decrease fq
RIGHT - increase fq
PGDWN - decrease fq 100MHz
PGUP - increase fq 100MHz
KEYUP - increase BW
KEYDN - decrease BW
ENTER - exit app.

The 3m dish is quite narrow, so i had to find a way how to catch the radio source in a Swan constellation. When i used it for the 5.7GHz Moonbounce i just mounted a camera and a noise meter to track the moon,.. but a decade later, there is a nice gadget on my mobile phone, a software called SkEye, so i just placed my phone to the back of my aluminium dish, calibrated it on a noise source (sun) and voila, precision tracking is now available ;). While tweaking hardware, the swan flew away down to the horizont, and the next target was Orion. I managed to get a first clearly visible hydrogen line there. 

Hydrogen line is clearly visible, antenna pointed towards ORION.

 

osmocom_fft picture of orion Hydrogen line. DC spike in center.

tracking the objects in the sky with a mobile phone

Allignment with the SUN

S57UUU & his Paprika-feed, broadband from 1.2-1.5 GHz

details

mounted paprika-feed