BRAMS Newsfeed
Test of the beacon in Dourbes
Last thursday (12/05), we made some tests with the beacon in Dourbes to simulate a metallic reflector of size 6m x 6m and 8m x 8m (using aluminium sheet of papers).
- The beacon was shut down at 12h15 local time (10h15 UT). First image below shows data before the shutdown.
- The test with the 8m x 8m "grid" was made from 15h15 (13h15 UT) to 15h45 (13h45UT). See second image below.
- The test with the 6m x 6m "grid" was made from 15h52 (13h52 UT) to 16h00 (14h00UT). See third image below.
The spectrograms clearly show that the direct signal is strongly attenuated (although still visible) and the number of reflections on planes has also strongly decreased. The intensity of the plane echoes is also strongly reduced.
Installation of the individual stations
We started this week the installation of the first receiving stations of BRAMS. The first one was successfully installed on 11/04/11 in Kampenhout at Felix Verbelen's house. Then the second one was installed on 12/04/11 on the roof of MIRA's observatory in Grimbergen. Below you can see 2 pictures from the antenna on the roof of MIRA and 1 picture of the station in Kampenhout. We will contact each of you individually when we are ready to install the material at your local place or when the material is ready to be picked up at BIRA.
VLF antenna in Humain
The VLF antenna has been installed in Humain. It is a magnetic field loop type of antenna with an area of about 50 square meters. The mast is 12 meters high. On the pictures below you can see two perpendicular loops oriented N-S and E-W which will allow us to measure both components of the magnetic field (or listen to the VLF emissions in stereo). The primary goal of this antenna is to detect whistlers but since it will be located next to our future VHF interferometer, we will look for conjunctions of VLF emissions and VHF meteor echoes (as was done during dedicated campaigns by Jean-Louis Rault).
Beacon in Dourbes - VLF antenna in Humain
The beacon in Dourbes is emitting since 21/09/10 around 14:00. Pictures of the beacon are available in the related section. Nice spectrograms have already been posted by Jean-Louis Rault (South of Paris), Peter Knol (Appingedam, north of Netherlands), Karl-Heinz Gansel (Dingden, Germany), Jacques Gruson (Guéthary,south of France) and of course by several members of the VVS. Unfortunately, the direct signal is quite strong for closer receiving stations and we will try to improve this in the coming weeks. Also, the VLF antenna in Humain has been installed. Pictures and details available soon. Associated electronics and receivers should be installed before the end of the year.
Some nice recordings obtained during the peak of the Perseids
Three examples of the data recorded last night with the AR-5000 and the simple Yagi antenna.
Recent news about the BRAMS network
- The station in BISA is now operational. We have been observing since tuesday 09/08/10. All antennas are currently listening to the Ieper's beacon on 49.99 MHz. The simple Yagi antenna is connected to the AR-5000 receiver while the two antennas from the crossed Yagi are connected to ICOM-R75 receivers. The ICOM-R75 receiver cannot add phases so at the moment we are simply recording both polarizations without adding them. Later on we will use the USRP2 receiver for that purpose. Below we give a nice example of an overdense echo observed around 06:00 AM on 12/08/10 to illustrate the differences in sensitivity and noise level of the AR-5000 (left) and the ICOM R-75 (right):
- The tests with the new beacon in Dourbes will start within the next 2 weeks. We will let everyone know when the beacon is emitting.
- The works to build the interferometer in Dourbes have started last wednesday. Tranches have been digged and concrete blocks have been made. At the end of August we will install the VLF antenna (more details soon) and in September we should install the 5 Yagi antennas for the VHF interferometer. Below are some pictures of the works:
Description of material supplied by BIRA for future stations of the BRAMS network
The material BIRA-IASB will supply for each station is the following:
- one commercial receiver ICOM IC-R75
- one 3-element Yagi antenna (with a mechanical part allowing to easily adjust the tilt-angle)
- one GPS clock (although we are still working on the code to efficiently use them)
- some 50 Ohms coaxial cables with the adequate length.
For those interested to host such a station, we kindly ask you to provide us an estimate of the length of the coaxial cables you would need.