Hacking is not the prerogative of digital: FM waves can also be targeted. Yesterday evening, France Inter listeners located in eastern Paris were surprised to hear a pirate program on frequency 87.6 – on which France Inter could usually be received.
Instead of the announcement of the results, we could hear a monologue of about fifteen minutes, turning on a loop and denouncing the politicians, the technocrats and the journalists in a voice apparently modified to make it unidentifiable.
A cheap hack?
With AFP, the spokespersons of the station indicated that a “pirate transmitter blew the frequency of the station”. The director of France Inter, Laurence Bloch, also published a tweet in the evening indicating that the teams of the company were working to understand what happened to prevent it from happening again.
The snippet, which was taped by multiple listeners, appears to have aired for around two hours starting at 8 p.m. It was obviously heard only by listeners located in eastern Paris. The technique used does not appear to be overly complex or sophisticated, as explained by Xavier Mouton Dubosc, volunteer at radioFMR and host of the program CPU: “It’s not very complicated. You must have equipment to transmit, which can be obtained for around 200 euros, then position yourself on a high point, such as a roof or other, and you can quite easily transmit “over” a frequency. »
Equipment for broadcasting on FM waves is not subject to any particular regulations concerning their possession, only their use is regulated. And the technique is not new either, since we find traces of this type of hacking as early as 1903.
Disturbances between two towers
If the author of this pirate broadcast mainly targeted eastern Paris, it is because this part of the Paris conurbation is a special case in terms of radio waves. The presence in this area of two huge antennas located at the top of the Mercurial towers has caused major problems with the transmission of radio waves since the early 2000s. Inconveniences which had prompted the inhabitants of the sector to express their dissatisfaction. It was indeed impossible for them to receive Radio France broadcasts due to the disturbances caused by the antennas of the Mercuriales towers.
To remedy the problem, the CSA (today Arcom) had indicated to the Parisian having authorized the installation of a “comfort transmitter” located in Bagnolet, in order to enable the inhabitants to receive Radio France broadcasts. For approximately 40,000 inhabitants of the area, France Inter can thus be picked up on the 87.6 frequency via this transmitter, while the rest of the Paris region listens to it on 87.8 by picking up the FM waves emitted by the antennas located on the Eiffel Tower. .
This transmitter, listed on the CSA site, nevertheless has a particularity: that of only transmitting at a maximum power of 100 watts. “It’s a very low power, especially if we compare it to that of the Eiffel Tower which goes up to 10 kilowatts”, explains Xavier Mouton Dubosc. It is therefore all the easier for a pirate to broadcast on the 87.6 frequency in the east of Paris and to “crush” the signal from the transmitter responsible for relaying France Inter in this area.
Measured risks
This type of radio wave piracy is illegal: as lawyer Alexandre Archambault reminds us on Twitterthose responsible are liable to a penalty of up to six months’ imprisonment and a fine of 30,000 euros, together with the confiscation and destruction of the equipment used.
In fact, those responsible are unlikely to be worried: the broadcast stopped by itself after two hours. It is technically possible to find the origin of a disturbance of this type by using “direction finding” techniques. This technique is used in particular by agents of the national frequency agency (ANFR) to find the source of a disturbing signal. But this no longer works once the signal in question stops.
Contacted, the agency nevertheless indicates that it has not received a request concerning this incident, and refers to Arcom, in charge of the allocated frequencies, for most of the questions. Asked, the Arcom had not answered our questions at the time of publication of this article.