Messages

1

HF Mystery Signals / Re: Mystery signal question

« on: January 06, 2015, 0108 UTC »

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.

Can't hear the sound files that were posted earlier in this thread, since they've apparently been deleted, [...]

Welp.

Time to repeat my request, I suppose.  SMF administrators can override maximum attachment size limitations, if memory serves.  So can one of you please preserve these as attachments to my original posts?  Here they are again:

From my September 12 post: http://s000.tinyupload.com/index.php?file_id=07669869441791435247
From my September 19 post: http://s000.tinyupload.com/index.php?file_id=32944569909504757660
From my September 29 post: http://s000.tinyupload.com/index.php?file_id=04057650744254842337

P.S.  Glad to see this thread still going.  Very interesting findings lately as well.  In particular, the waterfall OldSeaRock is quoting in the post immediately preceeding this one is astounding.  From the looks of it, it almost appears that the band needs to be de-wormed!  Maybe that's the nickname these things should be given.  "Screaming worms."  Screaming because they're audible worldwide, and worms because of how they appear on spectral graphs.    Anyway.  I hope the explanation will someday be found.

2

HF Mystery Signals / Re: Mystery signal question

« 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

3

HF Mystery Signals / Re: Mystery signal question

« 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.

4

HF Mystery Signals / Re: Mystery signal question

« on: September 19, 2013, 0958 UTC »

Fascinating, Rockpicker.  I'm also surprised that nobody really seems to know what causes these anomalies.

Anyway, I might have another clue to offer, one observed just minutes ago.  I spotted what appears to be the same signal phenomenon, only this time in the middle of HF band.  The only difference: the signal was not sweeping down or up in frequency.  It was completely stationary.  Furthermore, there were at least twenty iterations of it, evenly spaced across 2.6 MHz of spectrum.  Some screen captures (they go from high zoom to a wide view, and in the final image, you can see the signal's numerous iterations spanning approximately 5575 to 8200 kHz):

http://i.imgur.com/fsQFKDZ.png
http://i.imgur.com/Eypbmkt.png
http://i.imgur.com/o7j7xUF.png
http://i.imgur.com/eZopdUq.png

And to my ears, it does sound like the same phenomenon as on 27-28 MHz.  It may not be immediately apparent (because of it not sweeping through the receiver's IF), but to me, it has the same warbly/fluttery sonic signature.  Recording (two instances back-to-back): http://s000.tinyupload.com/index.php?file_id=07301278353252032862

Incidentally, I went up to 27 MHz upon noticing this, and sure enough, the phenomenon was happening there simultaneously (only there, in the same sweeping form I described earlier):

http://i.imgur.com/LKYxruz.png
http://i.imgur.com/5zyMQg7.png
http://i.imgur.com/vpe5b1z.png
http://i.imgur.com/uYCHxab.png

Sure would be nice to figure out what this thing is!

5

HF Mystery Signals / Mystery signal question

« on: September 12, 2013, 1434 UTC »

Can anyone identify the attached mystery signal?

I've personally observed it only in the 11 meter citizen's band, though that doesn't mean I'm saying it never happens elsewhere.  I often see it between 27.0 - 27.3 MHz, and only when skip/propagation is in.

It has been happening for decades (earliest memory: late 1980s).

It can be received with tuners in both Europe and North America (and possibly other locations).

I first assumed it was an ionosonde, but now have doubts because:

1) Instead of a sinewave (like an ionosonde), it consists of a "warbly" up-down-up-down sweep tone.

2) That warbling tone itself descends in frequency (rather than ascending, as normal chipsounders do).

3) And it only descends 40-50 kHz.  I.e., it begins instantly (no fade-in), descends 40-50 kHz, then stops instantly (no fade out).

Here are several audio samples of it, edited together.  Note that I used Twente's WebSDR in DSB reception mode.  That allows it to be heard as it sounds when crossing through AM carriers.

http://s000.tinyupload.com/index.php?file_id=93766677053675299202

Finally, I should note that there appear to be two variations of this mystery signal:

Variation 1:  Same as pictured above.  While observing it yesterday, it always lasted 4 seconds, and then reoccured every 13 seconds.  With this variation, the rate of frequency descent slows just before the signal vanishes (i.e., you see a diagonal line slowly curve into a vertical line).  Sometimes, the signal even reverses direction (goes back up in frequency) just before vanishing.

Variation 2:  This variation always lasts about 15 seconds (i.e., it descends in frequency much more slowly).  Unlike the first variation, its rate of descent does not slow before the signal vanishes, nor does it reverse direction and go back up.  Therefore it always appears as a diagonal line on waterfalls.  This variation also has a longer duration between occurences (30 to 60 seconds, guessing).  Nonetheless, it sounds audible exactly the same as the first variation when it passes through your receiver's IF (same warbling sweep effect).

Any ideas?