Category Archives: RAIOASTRONOMY

Detected meteor that has crossed tonight over Catalonia

Tonight, I was recording the Graves radar frequency (143.050 MHZ) to see I can detect the 2014 RC asteroid without success. But over a nice meteor has crossed Catalonia at the 04:56:50 UTCΒ  and has ben detected πŸ™‚

bolid

Meteor detected

The signal not is specially strong, because the target was very near from me. Using the Graves radar is more easy see meteors that are impacting from more remote locations of France or Italy

Other meteors can be observer before and after the target

Graves radar to UTC correlation

The Graves radar uses a multibeam antenna system that is switched every 0.8 seconds. When a meteor is detected and prints a large trace, is easy to see the beam switching after the meteor.

Graves beam switching

Graves beam switching

As the Graves radar system uses the transmitter and receiver in different geographic locations, is easy to think that they are synchronized the the UTC.

To check if it is true Miguel EA4EOZ and me are doing stereo recordings stereo of the Graves radar in one channel and a 1PPS signal from a GPS receiver in the other channel. And efectively they areΒ  locked to the UTC πŸ™‚

Graves radar 1PPS correlation

Graves radar 1PPS correlation

The coincidences to UTC are in the second 0,4,8,12,16,etc.. of every minute.

Some usefull info can be readed on the PE1ITR website.

PE1ITR, Greaves beam diagram

PE1ITR, Greaves beam diagram

Detecting Juno spaceprobe coming to Earth

This week he the enthusiasts os the space probes and the amateur-DSN are living a nice week dued the flyby of the Juno spacecraft. The flyby will be in the next October 9th.

Juno spacecraft

Juno spacecraft

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:

Juno received from EB3FRN station

Juno received from EB3FRN station

 

Perseids shower using graves radar

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.

Perseids meteor Graves radar

Perseids meteor Graves radar

To do the detector I used a rtlsdr receiver tuned to the Graves radar at 143.050 MHz, a ground planae VHF antenna and Baudline to display the scatters. Putting all toghetther using this script:

“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:

Dish Controller Rebuild

Starting the new season, I’m doing a lot of improvements in my system. Now I’m rebuilding the dish controller. The idea is get more mechanical precision and reduce the backslash. I hope improve the security too.

Dish Controller

Dish Controller

The selection of the speed and motion of the linear actuators was controlled by a ADAM 4068 relay module. It has been changed by a ADAM 4052 Digital input/output module, to reduce the reaction time and reduce the backslash. Now the ADAM 4068 relay module is used as watchdog to stop all if the comunication with the linux server is lost. I added a Emergency stop push button to the controller box.

Inside Dish Controller

Inside Dish Controller

Finally I added a RFI EMI power line filter and some ferrite core filters to reduce the RFI noise that was generating the controllner in HF.