What is RAMBO



RAMBO (Radar Astrofilo Meteore BOlogna) is a meteor radar built by the meteors research section of the the Amateur Astronomers Association Bologna (AAB) and realized in Bologna (Italy). The project goal is to receive and recorder meteors echoes.

RAMBO has been running since 2013 May and every year measure and collect near one million of meteors.

A meteor radar uses an atmospheric physics property: when a body (meteor, debris, etc.) enters at high speed in the upper layers of Earth's atmosphere it is strongly braked down.

Because the friction the body is brought to a very high temperature (2000-3000 K). Thanks to this, it emits visible light and ionizes a large amount of atoms in the surrounding of its atmosphere trajectory.

So, it create a long, narrow cylinder of strongly ionized air that persists for short time before his disappearance.

From a radioelectric point of view this cylinder is a reflective object, like an aircraft, a satellite or to any other flying object.

The radio waves reflection is called "Meteor Scatter".


– The meteor scatter process -


If there is a radio transmitter which illuminates a specific portion of the sky and a receiver tuned to the same frequency, we can record the received radio signal echoes and evaluate their characteristics.

To construct or purchase a power radio transmitter we need a lot of money, therefore for an amateur association it is impossible to do. So we have to use a transmitter of others.

RAMBO is tuned to the signal emitted by the military transmitter radar GRAVES (Grand Réseau Adapté à VEille Spatiale) in Dijon (Central France) that continuously works in the VHF with a very great power. His carrier frequency is 143.05 MHz.


Graves

– Azimut to Graves -



Graves

– One antenna of Graves -


Its transmission is directed in the high part of the atmosphere. For this reason, and because the Alps shield, it is not directly detectable from Bologna.


Graves

– Our antenna in Bologna -


Our receiver has a directive Yagi antenna pointed toward Graves in azimuth direction and in declination at about 25 degrees; where we had calculated to be the reflection point in the upper atmosphere (about 100 km).


Graves


Thanks to a microprocessor, the audio signal produced by the receiver is analyzed in frequency and digitized: in this way each meteoric echo is recorded in a text file in which we put the following parameters: