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Author Topic: 25 meter band hit by broadband noise, possible jammer  (Read 2818 times)

Offline Token

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25 meter band hit by broadband noise, possible jammer
« on: January 13, 2013, 0327 UTC »
Hello all,

For the past 5+ hours the 25 meter band has been hit by broadband noise.  This noise is very similar to what might be seen from an PRN or similar radar, but I have not seen such an application in HF before.  I have no idea if this signal is unintentional or if it is intentional, I suspect intentional.  What its purpose is again I do not know.

The signal is very wide, covering roughly 11250 to 11900 kHz, with it speak around 11610 kHz.  It is not a local signal to me, it was first reported on the east coast at around 2150 UTC and at that time I could not detect it at all.  As the evening progressed the signal started coming out of the noise for me.  Around 0100 UTC it was strong enough to wipe out many broadcast stations in that band.  At this time (0320 UTC) it is starting to fade, but still has significant strength.

The signal appears strongest on east coast (USA) remotes but can be detected on European remotes also.

At least twice the signal has paused for a short time, on the order of one or two seconds, once at 0023 UTC and once at 0303 UTC.  I have no idea if it did this other times or not, I was not watching it the whole time, those are just the ones I noticed.  During the pause the absence of signal makes the total width covered very obvious.

0023 UTC pause:


0303 UTC pause:


Hopefully it goes away soon, and does not become a regular fixture.

T!
T!
Mojave Desert, California USA

cmradio

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #1 on: January 13, 2013, 0558 UTC »
Wow! The TX power required to do that! :o

Peace!

Offline Chanter

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #2 on: January 13, 2013, 0611 UTC »
It sure was audible here in the Midwest.  I wondered what the heck was going on!  Still do.  What a mess. 

If this keeps up, there's no chance of Radio Australia tonight, or Radyo Pilipinas tomorrow.  Rats! 
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Nella F.

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #3 on: January 13, 2013, 2219 UTC »
It sure was audible here in the Midwest.  I wondered what the heck was going on!  Still do.  What a mess.  
If this keeps up, there's no chance of Radio Australia tonight, or Radyo Pilipinas tomorrow.  Rats!  

R. Australia loud & clear a couple of hours ago 11.880.
 
                                  >:(
           >:( Just what we need: More Noise! >:(
                                  >:(
« Last Edit: January 13, 2013, 2253 UTC by Nella F. »

Offline skeezix

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #4 on: January 14, 2013, 0101 UTC »
Doing plenty of damage here tonight.

Minneapolis, MN

Offline ChrisSmolinski

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #5 on: January 14, 2013, 0138 UTC »
Yep, I noticed it here as well.
Chris Smolinski
Westminster, MD
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Offline Token

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #6 on: January 14, 2013, 0237 UTC »
It came up here tonight prior to 2300 and at 0235 is still going strong.  More pauses in it tonight than last night though, and longer pauses.  Also, at one point, it stepped down in power at least 20 dB, while not going off the air.

Pauses:


T!
T!
Mojave Desert, California USA

Nella F.

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #7 on: January 15, 2013, 0105 UTC »
 >:(  Oh, that noise. I remember hearing it last year while waiting for India on 11.67 to hop accross the pond. Listening last afternoon & evening it was louder than usual; probably due to sunspot stuff.  >:(

Offline glimmer twin

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Re: 25 meter band hit by broadband noise, possible jammer
« Reply #8 on: January 16, 2013, 0110 UTC »
This has been going on for a few days now . It is likely being caused by a faulty transmitter on 11780 RNA/RNB in Brazil. There has been a lengthy discussion about this in the dx listening digest yahoo group over the last 3 or 4 days. It seems more than a coincidence that when RNA/RNB on 11780 starts ,so does the noise. It's been going on since Sunday 1/13.

Scanning the 25 m band at 23:20 UTC on 1/16 it seems all clear. RNA/RNB is on 11780 & no problems here. ZYE727 is doing well on 11765 with that nutty preacher in Portugese. KSDA & RTI are clear (or I should say clashing) on 11700 & North Korea's Home service is audible on 11680. Maybe the problem plaguing the band is solved.

Last night (1-18) around 4:00z the band was better.  There was a funky FM like signal on 11670 that matched up with RNA/RNB's 6180 signal so they have not quite solved the problem but they have improved things. I wish they would just take the screwed up 11780 tx off air & use a dummy load to test it until it's fixed.
« Last Edit: January 19, 2013, 0348 UTC by glimmer twin »
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