3x OTHR within the 40m-Band
Intruders are non-amateur radio band intruders in the exclusive amateur radio bands on shortwave, which have been allocated to the amateur radio service up to 30 MHz for sole or primary use by the amateur radio service in accordance with the International Telecommunications Treaty in conjunction with the Amateur Radio Ordinance.
A band intruder is therefore a foreign radio service that uses our frequency capacities unjustifiably.
In the german context, this is governed by the Amateurfunkverordnung (AFuV), Anlage 1 (zu § 1 Nr. 6).
The Intruder-Watch interest group deals with unauthorised use of the exclusive amateur radio shortwave bands by foreign radio services.
Foreign radio services in the exclusive shortwave bands.
Does that exist? And what do they do there?
We radio amateurs actually have free use of the exclusive bands. This is because exclusive means that we can use the frequencies there on our own. As a rule, we do not have to share them with other radio services.
In reality, however, things look different. There are a lot of foreign signals. At first glance, you might think: OK, that's an amateur radio procedure that I don't know yet.
At second glance, however, you might realise that, for example, the bandwidth of the transmission cannot actually belong to any amateur radio procedure. Or that the shift of an RTTY signal is atypical. In this case, it could be a band intruder.
We are always happy to receive reports of intruders.
On this basis, we consolidate the information and forward it to the relevant authorities as required so that the necessary steps can be taken to stop the illegal mailings.
In contrast to an association-bound band watch, as an independent working group we can also contact transmitter stations directly via our dense network and thus, for example, inform transmitter providers about faults in their systems via the short official channels.
Unauthorised use of the amateur radio bands occurs when a foreign station uses the 40, 20, 17, 15, 12 or 10 metre bands, because according to the international telecommunications treaty, these bands are exclusively allocated to the amateur radio service.
These include, for example, radio transmitters or their harmonics, digital operating modes - such as Morse telegraphy, radio teletype or multiplex transmissions from the military, embassies or international organisations - radiotelephony traffic from the aforementioned user group and private radio pirates in the SSB (single sideband modulation) operating modes, AM (amplitude modulation) and FM (frequency modulation), various (mainly military) digital operating modes, over-the-horizon radars, marine wave radars, drift net buoys or illegal taxi and community radio.
The following example shows three over-the-horizon radars that occupy large parts of the 40 metre band:
3x OTHR within the 40m-Band
