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Author Topic: Mystery signal question  (Read 65495 times)

Offline skeezix

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Re: Mystery signal question
« Reply #15 on: September 22, 2013, 1754 UTC »
The sweeper that you hear is probably an ionosonde.


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Offline jcwilshire

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Re: Mystery signal question
« Reply #16 on: September 26, 2013, 0919 UTC »
I'm almost positive that these cannot be ionosondes.  The ones which appear in the 10-11 meter range only sweep 30-40 kHz of spectrum, as originally mentioned.  But now that I am actively looking, I am noticing that the ones appearing throughout the lower HF bands almost always remain on one frequency, each drifting possibly only 2-3 kHz over a period of minutes.  For example, as I write this, the 20 meter ham band is currently crawling with the things.  See first attachment (and second attachment for a close-up of one).

In any case, everybody seems to have verified that, as with my experiences, they only appear during skip.  So that also rules out sources of local RFI.


Edit: Would you or another moderator mind downloading the tinyupload.com sound files in my first and second posts, and attaching them to their respective posts (despite the attachment limits that apply to us mere users)?  I'd hate to think that somebody who knows the definitive explanation for these sounds might stumble across this forum in 9 months, only to find expired file locker links.  Many thanks.
« Last Edit: September 26, 2013, 0939 UTC by jcwilshire »

cmradio

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Re: Mystery signal question
« Reply #17 on: September 26, 2013, 1211 UTC »
For example, as I write this, the 20 meter ham band is currently crawling with the things.

OK, that is completely new to me and isn't an ISM band and would be rediculous for dielectric heating.

Having heard then on 11M since forever, I too would really like to know what they are.

Peace!

Offline Kage

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Re: Mystery signal question
« Reply #18 on: September 28, 2013, 1437 UTC »
Just dropping in to confirm that I have also heard this exact sound many times on the CB band.
Even when monitoring 27.185 when skip is strong I have noticed it, sometimes so strong that it wipes out DX for the short time it is on.
Always wondered what it was myself but never thought to question it.
Interesting how it is noted as far back as the 1960s here. That kind of rules out modern device RFI. Also the fact that it only happens during skip means whatever it is must be radiating really well to be heard by so many people across so many frequencies.
« Last Edit: September 28, 2013, 1444 UTC by Kage »
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Offline jcwilshire

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Re: Mystery signal question
« Reply #19 on: September 30, 2013, 0742 UTC »
Spotting more occurrences tonight on HF.  And here are some examples I encountered on 20 meters again, but this time quite strong, and also with a very slow warble frequency -- slow enough that with the WebSDR waterfall in fast mode, the warble is perfectly detailed visually.

http://i.imgur.com/O2Rx9oc.png
http://i.imgur.com/2dfq8Pu.png
http://i.imgur.com/1a1miy8.png
http://i.imgur.com/TEMTikP.png

Recording of two of them, as they pass from top to bottom through the WebSDR's 6 kHz wide USB IF: http://s000.tinyupload.com/index.php?file_id=09570432523318839701

Offline thechoat

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Re: Mystery signal question
« Reply #20 on: October 14, 2013, 1645 UTC »
caught these today on 27700u been going off and on for awhile this is the sounds i hear most often

https://archive.org/details/27700uOct142013StrangeSounds
« Last Edit: October 14, 2013, 1648 UTC by thechoat »
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Offline Cornel

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Re: Mystery signal question
« Reply #21 on: September 07, 2014, 0133 UTC »
I think we ALL heard these one or more times and since years. Here in Argentina i can monitor them daily on various frequencies, say 8-30MHz, and allways strong to vy strong. I my case i think http://ionos.ingv.it/tucuman/fplotMUF.html guys are xmiting the sigs. It would be interesting to know if that mode was also used in 1960s (and up). They xmit regardless of bandlimits etc. Signal sounds/looks scientific to me, not RFI. check ionos.ingv.net.

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Offline Token

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Re: Mystery signal question
« Reply #22 on: September 13, 2014, 0119 UTC »
Yes, I have heard these for decades on HF, many people have, but I think the wide spread use of waterfall displays have made them more obvious to listeners.

I am very certain these are not ionosondes of any kind.  First, the signals are far to narrow banded to be useful ionosondes, even if you look at all of them as coming from one source you end up with too many gaps.  Second, most ionosondes are well documented, as are their waveforms.  In the case of the ionos.ingv.it sondes and plots Cornel posted, that source uses the INS-INGV ionosonde.  Descriptions of the waveforms 16 bit complementary phase code can be found online…and it does not look like these things, and I think that one tops out at 20 MHz.  No documented ionosonde has a waveform even remotely resembling these.

As for what they may be, I have no idea.  I did once show an image of the signal to an engineer working with RF Induction heating, and he said they look something like what can be seen as a result of a low duty cycle pulsed RF Induction heating source, however he also said those are typically found below 4 MHz.

In my opinion they look incoherent and random with regard to amplitude and phase content.  I think that makes them unlikely to be intentional transmissions other than byproducts of some operation / hardware.  There is NO doubt they are fairly high power, I have received the same single transmission on multiple remotes located hundreds or thousands of miles apart before, but realistically that kind might be possible with fairly modest power levels.  It does not take thousands of Watts, but only hundreds or maybe even tens.

T!
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Offline Cornel

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Re: Mystery signal question
« Reply #23 on: September 19, 2014, 0047 UTC »
Thanks T. Interesting. I think i need a SDR :).
Soooo, why do we hear these sigs all over the world? Do they appear random, frequencie/time/direction wise? Maybe something "secret", undocumented.
I think we all agree it's not "mother nature" doing these. If it's just some RF garbage from inductive soldering or any other industrial action, why nobody complains cos of this RFI? I mean, if somebody does RFI over hundereds even thousands of miles, that would lead to investigation at least. No?
Do we hear these in the, lets say, MWARA/safety ranges of HF? What does the FCC/ITU say to this mistery? RFI is RFI. isn't it? If the source is industrial, then it must be an old "fashioned" process(es), we hear it since decades, and even today.

Strange indeed.
Only more questions, no answers.

C
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vhavrilko

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Re: Mystery signal question
« Reply #24 on: November 13, 2014, 0331 UTC »
I know this is an old post but it reminds me of a powerful signal that used to sweep 11 meters back in the 70s.  I remember a "sweeping carrier" that would peg the needle on my friend's Johnson Messenger 223 tube set.  Sometimes it would last several seconds and wipe out 11 meters and was extremely frustrating.  We lived in a small town in Pennsylvania (Kelayres) and my friend lived in the adjoining town (McAdoo).  We suspected it was an unintended electrical signal associated with some type of switching equipment from a local clothing manufacturing plant (McAdoo MFG).  It was only present during the day although the plant used to stay open until 2100 at  reduced activity.  It went away some time a decade later which probably was the result of a repair or replacement of whatever was causing the problem.  It was never reported to the FCC as far as I know.  I do not think it was atmospheric but localized. After I joined the USAF, I would visit home when I could in between PCS moves and always had access to 11 meters plus a general coverage receiver and it never returned.

Just out of curiosity, if the audio file is still available, please provide a new link.  The other link has expired.  I would like to hear what the signal reported in this message sounds like.

Offline Token

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Re: Mystery signal question
« Reply #25 on: November 13, 2014, 1533 UTC »
I think we all agree it's not "mother nature" doing these. If it's just some RF garbage from inductive soldering or any other industrial action, why nobody complains cos of this RFI? I mean, if somebody does RFI over hundereds even thousands of miles, that would lead to investigation at least. No?
Do we hear these in the, lets say, MWARA/safety ranges of HF? What does the FCC/ITU say to this mistery? RFI is RFI. isn't it? If the source is industrial, then it must be an old "fashioned" process(es), we hear it since decades, and even today.
 

At one time or another I think I have heard these on almost any frequency band, however they do tend to appear in a few more commonly than others.  Right now I am watching two hitting the 13150 kHz area, half a dozen hitting the 14400 to 15000 kHz area, and dozens from 26000 to 32000 kHz.  28400 to 30000 seem to be most densely populated.

It might be worth noting that those bands I just mentioned could be harmonically related.  Could this be some lower freq industrial RFI, say below 4 MHz, and we are seeing the harmonics when band conditions allow?  I have tried to match some lower freq sweeps to higher freq ones, to prove the harmonic relationship, so far unsuccessfully.

T!
T!
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Offline ChrisSmolinski

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Re: Mystery signal question
« Reply #26 on: November 13, 2014, 1604 UTC »
Would it be useful for as many of us as possible to check for these things, and post in real time when they are observed (IRC might be best). Then if folks could check sub-harmonic frequencies, we might be able to find the fundamental and general location, if someone is lucky enough to be nearby the transmitting source.
Chris Smolinski
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Offline jFarley

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Re: Mystery signal question
« Reply #27 on: November 13, 2014, 1952 UTC »
It seems as if we are all dumbfounded by these events.  I do believe that there may indeed be a terrestrial source for these bursts, and that's it.  Badda bing, badda boom.  But lately, I have been wondering if the source may be somewhere else.  Has it ever been suggested that we might be seeing radio bursts from, let's say, Jupiter?

http://science.nasa.gov/science-news/science-at-nasa/2000/radiojove_sbursts/

There is a lot of similarity between these Jovian S-Bursts and the emissions we are observing.  Maybe while we are checking for sub-harmonics we might also keep track of Jovian declination and ascension.

Is there an astronomer in the house?
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Offline ChrisSmolinski

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Re: Mystery signal question
« Reply #28 on: November 13, 2014, 2030 UTC »
I'm picking up some of these now, jFarley, right around 15900 kHz.

Interesting theory - Jupiter. I tried some time ago to listen to Jupiter but was never able to. I did write a prediction program for the radio bursts, let me dig it up and see what it shows for now.

I'll check on IRC and see if anyone else is picking these up.
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Offline jFarley

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Re: Mystery signal question
« Reply #29 on: November 13, 2014, 2039 UTC »
OK seeing a couple now.

The theory might be easier to disprove than prove?
Joe Farley, Near Chicago
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