Tag Archives: Jamming

In Sweden, Ambulances testing system to jam car radios

(Source: BBC News via Richard Langley)

Ambulances in Stockholm are testing a system that interrupts in-car audio systems to warn drivers that they need to get through.

The solution was developed by students at the KTH Royal Institute of Technology in the city.
It broadcasts a voice warning, while a text message also appears in the radio display.

It uses an FM radio signal to jam drivers’ speakers and stop music playing.

It will only be able to alert cars that have their radios turned on. It can also interrupt CDs and music connected via Bluetooth.

The radio transmission is sent from the emergency vehicle to nearby FM tuners that are equipped with RDS, a communications protocol for embedding small amounts of digital information in FM radio broadcasts. It is most commonly used to display the station or song title.

[…]The city will begin testing the system in a limited number of ambulances and fire engines, with plans to expand across the country later this year.

The warning system can work out how far in advance messages need to be heard depending on the speed of traffic.

Continue reading at BBC News…

Radio Eritrea and Radio Ethiopia jamming intrudes on amateur frequencies

eritrea-ethiopia

Many thanks to SWLing Post contributor, Vlado (N3CZ), for sharing the following story from the South African Radio League newsletter:

Broadcasters, jammers wreak havoc on amateur radio frequencies

The ARRL reports the battle in the amateur radio 7 MHz band continues between Radio Eritrea and Radio Ethiopia, which is said to be jamming the Eritrean broadcaster with broadband white noise

The problem for radio amateurs is that the battle is taking place in the 40 meter phone band 7,145 and 7,175 MHz with the jamming signal reported by the IARU Region 1 Monitoring System (IARUMS) to be 20 kHz wide on each channel.

The on-air conflict has been going on for years; Ethiopia constructed new transmitting sites in 2008 and is said to use two or three of them for jamming purposes. The interfering signals can be heard in North America after dark.

According to IARUMS Region 1 Coordinator Wolf Hadel, DK2OM, Radio Eritrea is airing separate programs on each frequency. He said in the IARUMS September newsletter that telecommunications regulators in Germany, Austria and Switzerland have been informed, so they could file official complaints.

Read the full ARRL story at
http://www.arrl.org/news/broadcasters-jammers-wreak-havoc-on-amateur-radio-frequencies

IARU Region 1 Monitoring System latest news
http://www.iarums-r1.org/iarums/latest.pdf

North Korea intensifies shortwave jamming

FlagNorthKorea

(Source: DailyNK via Andrea Borgnino)

North Korea has been from the beginning of March continually signal jamming radio broadcasts on the shortwave frequency used by the South Korean non-profit broadcaster Unification Media Group (UMG). Given the present situation, in which North Korean residents might be influenced by outside information condemning the regime and explaining the purpose of the sanctions imposed by the United Nations, the regime has showed the will to block sources of outside information that might cause unrest.

The shortwave frequency […] in question, 7515 [kHz], has been actively jammed starting on March 1st making it extremely difficult for North Korean listeners to tune in. On the 15, UMG organization began using three receivers to test out reception at that and adjacent frequencies on a daily basis and was able to confirm that the exact signal is being jammed.

The blocking effort is being concentrated on the time period from 10pm- midnight. Specifically, from 10-11pm the jamming is very strong. The signal jamming is undetectable from midnight to 1am. The signal blocking became weaker at midnight on March 15, from which point onward the entire three hour broadcast was audible. Starting on the 17, UMG moved the frequency, but the jamming operators seemed not to notice because the interference continued on the old wavelength.

Continue reading at the DailyNK online…

Empire of Noise: a documentary about jamming

Many thanks to SWLing Post contributor, Gary Wise (W4EEY), who writes:

I stumbled over an interesting documentary on radio jamming. You have probably seen it, but just in case you haven’t, here is a link.

I had not seen this before, Gary.  Thank you!

Is Firedrake on the decline?

(Photo: Satdirectory.com)

(Photo: Satdirectory.com)

Have you noticed less Firedrake broadcasts lately? I certainly have.  My buddy David pointed this out to me last week and since then I haven’t heard Firedrake even once. I have, however, heard the more aggressive and noisy Chinese jamming techniques.

Perhaps it’s just a “watched pot never boils” situation? I’m not sure; some SWLs on the hard-core DX reflector have also noticed a lack of Firedrake across the bands.

Have you heard Firedrake lately? Please comment with loggings.

For readers who are unfamiliar with Firedrake, check out this previous post.