How are radio frequencies interfered with?

Navigation and service

Where do the interfering signals come from?

Interfering signals can be caused not only by neighboring radio masts, but also by improperly installed satellite systems. A large part of radio interference is caused by defects and aging effects in electrical devices and radio systems, which lead to undesired emissions, emissions and repercussions on power and communication networks. In addition, radio interference is repeatedly caused by devices purchased on the Internet, the operation of which is not intended for the EU or which transmit on frequencies that are not intended for this purpose. It is therefore important that such devices bear the CE mark and that they are used correctly.

Read more about unsafe products.

In addition, cable television systems that are not adequately shielded can transmit interference signals. These can impair radio communication between the security-relevant services. Since 2010, the Federal Network Agency has been checking whether such cable television systems exceed permissible limits. If this is the case, we will inform the responsible cable network operator. More information can be found here.

What do I do in the event of radio interference?

1. Check for a device fault

Rule out a defect in your receiving device or in your antenna system. This is the best way to proceed:

  • Is your television or sound and radio reception system correctly set and suitable for the purpose?
  • Is there sufficient radio coverage?
  • Is the antenna connection cable OK and adequately shielded?
  • Is the antenna house distribution system OK? Your specialist dealer, repair shop or the house owner are your contacts to remedy the defects.
  • Do the devices used have a CE mark, e.g. garage door openers, door locks, baby cameras?
  • If you have a cable connection, please first inform your cable provider about the problem.

2. Contact the Federal Network Agency

  • Call the Federal Network Agency's radio interference acceptance department at 04821 89 55 55 or write an email to [email protected] The radio interference reception is available for you 24 hours a day, 7 days a week.
  • Give us as much information as possible, such as: B. the probable source of the radio interference and how and when the interference occurs.
  • If an on-site radio interference investigation is required, we will arrange an appointment with you on site. Our testing and measuring service is represented at nineteen locations nationwide.
  • Please note that on-site investigations are often very time-consuming. It is therefore important that you first check devices yourself for possible errors, e.g. B. the television set and the antenna system.

Help is not possible with every radio interference

If a disturbance occurs in a so-called "ISM" frequency band or with generally allocated frequency uses, we can only help to a limited extent. ISM frequency ranges are frequencies with so-called mixed use. In these frequencies, radio systems with low power and range are also operated in large numbers for different applications that influence each other. Such mixed frequency uses cannot be avoided, since radio frequencies are a scarce commodity for physical reasons. Despite the large number of devices operated here, however, it occurs relatively rarely. In special cases, mutual incompatibilities cannot be completely ruled out, but these are limited in terms of location and time. This can affect radio systems such as garage door openers, immobilizers, door locks, barcode scanners, baby monitoring systems and some CB radio channels. All these uses must share the common frequency band; the general frequency allocation does not provide for a priority of certain users.

From our work

  • The testing and measuring service of the Federal Network Agency has found a VHF pirate transmitter in the attic of an apartment building in Düsseldorf, which is causing interference. This illegal radio station automatically switched all radio participants to the pirate station via a manipulated RDS signal. Communication in emergencies and disasters was also affected. German pop music could be heard on the radio and an ALARM message could be seen on the radio displays. The transmitter has been taken out of service.
  • A homeowner reported regular interference with his radio reception. Our measurement technicians were able to determine that the malfunction was caused by a remote-controlled garage door opener from the neighbor.
  • One person reported to the Federal Network Agency that his wireless car key was not working in a certain place next to his house. On the other side of the house, the key worked perfectly. Our measurement technicians found a commercially available, small weather station in the neighborhood that was working on the wrong frequencies due to a defect.
  • Bremen Airport reported a malfunction signal in communication between the tower and the cockpit. After an extensive investigation, our measurement technicians found a marten distributor in the attic of a family house near the airport.

Chasing jammers: a portrait of one of our test and measurement technicians