Thanks for doing this Chris.   The subtleties are endless.

Couple of questions. These are all originating in South Korea, is that correct? (except for video games on 819?)
\\

further:
This is the Gimpo siren jammer, THE most powerful jammer in Korea at 250kw, aimed south and on 16 1/2 hours a day, yet still stupidly leaving a full hour a day unjammed. While it's the most heard in the country, the dinky Seoul jammer 16 miles away is the one that gets out across the entire globe but can barely cover a 50-mile radius in Korea. We suspect its power is going up to the sky (or due north) as opposed to covering the ground as it should be.

Gimpo being in South Korea, what is it jamming from the south? (which might be why we don't hear it on northerly paths?) This siren is what I heard on 1053 years ago, have a recording from 2007; the recordings from 2008 are without sirens. I don't think I've heard the sirens since then.





This one is used at tourist sites along the DMZ. This is recorded less than 10 miles from the tower of 50kw 810 KCBS while standing beside the North Korean customs booth a half mile from the actual border, but a 60dBu silent signal very closeby is muffling it. These are mounted on little sticks on the side of buildings like 10-watt transmitters.



I've heard something like this earlier this year on 1566. They're taking the audio of the originating station, distorting somehow and rebroadcasting?

best wishes,

Nick



At 09:45 29-11-16, Chris Kadlec wrote:
Here's a little bit about different jammers on the South Korean side of things for those who are interested. I have been sifting through 40 hours of unedited recordings of East Asia MW over the past week or so and can now view them in a more organized fashion than when I presented on the same topic in Madison last August (for the few of you who attended) with basically no preparation whatsoever. I'll leave the North Korean side of things for another time as they have their own unique sounds, especially the big metro Pyongyang frequencies (891, 900, 1143, 1467, 1566, and 1584, not to forget the freaking 75 kHz-wide 711 that wipes out a fair chunk of the Seoul daytime band).

I'd like to share nine clips. Some are experimental while others are 24/7 permanent. The experimental site south of Seoul just came online with 24/7 full-power jamming with the obvious end result of their long-term testing and I'm not including that in here, though it's not drastically different from what's heard here (just more annoying).

First, here's the most basic form of the jammer the ROK has been using for some time. It's just the raw sound with nothing additional added in yet. This was at the experimental site 7 miles from my FM site.

http://www.beaglebass.com/dx/external/Jammer_Basic.MP3

Next, this is the standard jammer that has been used more or less for the past year in Seoul. Note the same sound with sirens added. There are minor differences now and then.

http://www.beaglebass.com/dx/external/Jammer_Standard.MP3

My arch-nemesis, the hum jammer. They're using these on multiple frequencies and via skywave and groundwave, I cannot identify the locations and they clog otherwise-listenable frequencies from China. This particular one is on 855 and near the coastal border.

http://www.beaglebass.com/dx/external/Jammer_Hummer.MP3

This is the Gimpo siren jammer, THE most powerful jammer in Korea at 250kw, aimed south and on 16 1/2 hours a day, yet still stupidly leaving a full hour a day unjammed. While it's the most heard in the country, the dinky Seoul jammer 16 miles away is the one that gets out across the entire globe but can barely cover a 50-mile radius in Korea. We suspect its power is going up to the sky (or due north) as opposed to covering the ground as it should be.

http://www.beaglebass.com/dx/external/Jammer_Siren.MP3

Put them all together - the basic, standard, siren, and hummer, and you end up with this. This is a single jammer near the experimental site, meaning they have added it all together into one signal for that day anyway.

http://www.beaglebass.com/dx/external/Jammer_Angry.MP3

This one was heard in mid-June from the southern experimental site. I'm not even sure how to describe it... like a rubber band rapidly hitting something over and over. Annoyingly effective, but just a test. Never heard before or since.

http://www.beaglebass.com/dx/external/Jammer_Static.MP3

This one is used at tourist sites along the DMZ. This is recorded less than 10 miles from the tower of 50kw 810 KCBS while standing beside the North Korean customs booth a half mile from the actual border, but a 60dBu silent signal very closeby is muffling it. These are mounted on little sticks on the side of buildings like 10-watt transmitters.

http://www.beaglebass.com/dx/external/Jammer_Low_Power.MP3

My favorite of all: the "now you hear it, now you don't, ha ha!" jammer from the southern experimental site. 1 min 40 sec of jamming, 40 seconds of no jamming, repeat. Local 657 Pyongyang can be heard in the lack of jamming, at noon.

http://www.beaglebass.com/dx/external/Jammer_Intermittent.MP3

And lastly, there is the jammer warfare with the two sides jamming each other. The video game-like jammer is 819 Pyongyang. The other jammer is the standard Seoul jammer.

http://www.beaglebass.com/dx/external/Jammer_Warfare.MP3

-Chris Kadlec
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Nick Hall-Patch
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