[2015-08-19]Manual counts during Perseids 2015
The figure below shows an example of a spectrogram where red rectangles have been manually drawn around meteor echoes.
The 3 graphs below show successively :
The raw counts (obtained for each spectrogram every 5 minutes) including all meteor echoes (long and short). The peaks of the Perseids are nearly impossible to spot as the total number is a mix between Perseids and sporadics. The red curve is a moving average on 11 points (so more or less 1 hour) and shows some peaks but not very clearly.
Hourly raw counts including all meteor echoes (long and short), simply obtained from the first curve by adding individual counts for all spectrograms in one hour. The peaks of the Perseids become visible but again not very clear.
Hourly counts including only long meteor echoes. The definition of long is rather vague but includes basically all meteor echoes that have an horizontal extent in the spectrograms, indicating a long duration than typical short (underdense) meteor echoes that represent the bulk of the sporadic background. Then, in this plot, two peaks at ~ 5 UT and ~ 8 UT become visible. These are in agreement with meteor counts obtained by Felix Verbelen using the Ypres beacon at 49.99 MHz. It would be nice to compare these observations with visual observations (see e.g. this page at IMO).
[2015-08-17]Beacon switched off on 17/08/2015
[2015-08-13]Perseids 2015 at ROB
[2015-08-10]Beacon off on 07/08/2015
[2015-07-20]Beacon off during last week-end
[2015-07-03]Calibration tests in Dourbes done
The drone was flying in the far-field of our antenna. The far field is approximately located at ~ 2 D^2/lambda with D being the largest size of the antenna. In our case, with a 8m x 8m grid, D is equal to the diagonal of the reflecting grid and therefore the far field is located at approximately 43m. The drone was flying in circles at a distance of 50 m from the bottom of the antenna. Each circle was carried out at a different elevation (between 30° and 80° with steps of 10°). 30° was the minimal elevation to be sure that the drone was flying way above the tallest trees nearby. For each circle, 36 positions were considered to span the whole azimuth angles with steps of 10°. The drone was staying 15 seconds at each position.
Below is a picture of the drone flying above the nearby trees.
[2015-07-01]Calibration tests in Dourbes
[2015-06-29]BRAMS annual meeting at MIRA observatory on 27/06/2015
- Recent advances in the BRAMS project - H. Lamy
- Amplitude calibrator for the BRAMS stations - M. Anciaux
- Power profiles of radio meteors - S. Calders
- Etude du profil d'un écho underdense - P. Ernotte
- Calibration measurements for the BRAMS network - S. Ranvier
- The BRAMS Zoo project
- Update of the FRIPON project and the determination of meteor trajectory - J. Vaubaillon
- Using the BRAMS beacon for studying meteor induced VLF propagation disturbances - J-L Rault
- Head echoes - F. Verbelen
[2015-04-08]New BRAMS station installed in Maasmechelen
As can be seen, antennas will from now on be installed vertically. We have also installed the amplitude calibrator that will progressively be added to all BRAMS stations.
[2015-02-19]New antenna at BEUCCL