Listen to the meteors


[2010-10-12]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).

[2010-09-27]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 (Gu├ęthary,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.

[2010-08-12]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.

[2010-08-12]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:

[2010-07-28]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.

[2010-07-09]Status of the BRAMS network

1. Beacon in Dourbes :

  • Nearly all the material has arrived : signal generator, power amplifier, antenna (built in the workshop). Only coaxial cables are missing.
  • We have visited the Dourbes site and have an agreement to use a specific place where we will install the beacon. Here are a few pictures of this place :

  • For the initial tests in Dourbes, we will use a two-element Yagi antenna like the one in Ieper. These tests will also allow us to check we do not perturb the other instruments located on the Dourbes site. Later on, We will use a metallic grid of 8 m x 8 m as the reflecting part instead of the simple reflecting tube of the Yagi antenna. With this configuration, the gain will be significantly larger. We will work on this grid during the summer.

2. The station in BISA :

It is located next to our institute, in the KMI/IRM park. We have 2 antennas : one three element Yagi listening to 49.99 MHz and one crossed three element Yagi listening to 49.97 MHz. Here are some pictures:

3. The network :

  • We have 20 ICOM IC-R75 that eventually will be given to every station of the network to listen to the new frequency 49.97 MHz
  • We have GPS clocks available for every station (more details about them in another e-mail soon)
  • Twenty 3-element Yagi antennas are under construction at the BIRA workshop and will be distributed as well
  • We will ask everyone if they agree to host a station and who has enough space for it. We will organize a meeting in September/October in order to discuss this topic and maybe to start distributing the material.

4. The interferometer in Humain :

  • Works have started on August 4. Tranches have been digged and concrete blocks have been made.
  • We will also install a mast of 12 meters high supported by guy-wires which will act as a VLF antenna. Cables will be installed in a way to make a rhomb with a surface of approximately 50 square meters. This will act as a magnetic antenna. Although it will mainly be used to detect whistlers, we also plan to look for coincident VHF meteor echoes and VLF emissions.

5. Various :

  • Two students from Pierre Ernotte at EPHEC have worked on an automatic detection method of meteors in spectrograms in the framework of their master degree. They presented their results at BISA in June. We intend to continue the collaboration with these students during the summer (as summer jobs) and with other students from EPHEC next year.
  • An Action 1 proposal has been sent to Belspo (Belgian scientific policy) to get fundings for one scientist for a period of 4 years to work on and analyse the future BRAMS data.