Mystery signal question

[ChrisSmolinski]

I checked, and there are no Jupiter radio storms predicted for now.

Here is what I am seeing now:

[jFarley]

I checked, and there are no Jupiter radio storms predicted for now.

Oh well; would have been a tough QSL anyway...

Saw some unusual things today:



I have never seen the degree of "flaring out" near decay as seen today in the 2 on the right.  In between is one which seems to slow down its descent in frequency, and then descend some more.  A couple I saw today had a very pronounced reverse S curve.

[Token]

J, the flare at the end is a common feature seen here.  Also the shape can go back and forth, have seen them reverse, even make hard corners.

T!

[jFarley]

Thanks T!

[BoomboxDX]

Can't hear the sound files that were posted earlier in this thread, since they've apparently been deleted, but if it sounds like a type of warbly squish noise it's probably Jupiter.

I remember reading about it in the 1990's in PopComm or Monitoring Times.

I've heard the noise usually above 20 mhz, both in the CB band, and near that part of the HF spectrum.

[Token]

This may mean something, or it may not.

Today the bands are not quite as good as they have been all week long, however they are not in bad shape, 10 meters, for example, is packed.  Because there had been a request for a recording I stopped by the band several times to grab a recording of these signals to post to my Youtube channel.  However basically I am not seeing any of these signals today.  One or two stragglers, but nothing like the density of yesterday and the preceding 5 days.

Today is Sunday, and if these signals are byproducts of an industrial process might you be able to expect lighter traffic on Sunday in most nations?

Right this minute I see zero of these signals in the 10 meter band, or in any other band, but yesterday there were dozens visible at any one time.  I have seen a few of them today, but really VERY few.  I am thinking that can't all be conditions.

T!

[Token]

Now Monday morning, 1500 UTC, and I see these signals are back in normal numbers.

10800 to 11300 I see a couple per minute, 14600 to 15000 I see maybe 6 to 8 per minute, 16800 to 17200 I see maybe one every 20 seconds, 23050 to 23250 I am seeing a couple per minute, 28000 to 29000 I see dozens per minute, 37250 to 37750 I see 8 or 9 per minute.  I do see them in a few other frequency ranges, but those seem to be the most consistent.

I have scheduled 2 recordings a day to try and see if there is a daily cycle involved (i.e. was Sundays absence real or not).  I have a 1 MHz wide chunk of spectrum centered on 14500 and 28500 kHz scheduled for 1 minute every day at about 1500 UTC.  If I get around to it I want to log the number of sweepers seen in that 1 minute / 1 MHz chunk daily to see what the trends are.

As for Jupiter as a source, I think probably not.  These signals do not match either L bursts or S bursts from Jupiter.  They are too fast and narrow banded for L bursts, and the bandwidth is right for S burst but they are too slow.

Also, these signals do not seem to have any timing in common for when Jupiter is above the horizon or not.  I would think that if they were from Jupiter they would be more likely to be seen when Jupiter is above the horizon, and less when it was below, instead these signals seem to be tied to propagation conditions, strongly suggesting, to me, that they are terrestrial.  I would think that the same factors that make propagation good (radio wave reflections off charged portions of the ionosphere) would also make those bands less likely to show Jovian noise, since the signal from Jupiter would have to penetrate that layer.

(edit)  Interesting, in setting up the recordings I decided to use a directional antenna.  I found that the 10 meter sweepers are mostly coming from a different direction than the ones near 20 meters.

T!

[jFarley]

Good points all, T, and those last two sentences in particular are interesting... The case for a terrestrial source is indeed compelling.

I just have problems understanding the nature of the source, and why we are seeing these.  What sort of physical plant could be generating these decametric emissions?  Are the emissions themselves the process?  Are these leakages or spurious emissions?
Why do we see multiple simultaneous events as in the following?



Got me hanging!

[ChrisSmolinski]

I'm seeing a few around 16 MHz right now. Nothing else noted here, but I didn't try for long, time to set up for recording 6800-7000 kHz :-)

[Token]

As I said in my previous post, they appear to be from different directions, although so far the ones in a given frequency range seem to be from the same direction.  I would be real careful with that thought though, the data set is pretty small to start drawing conclusions.  In my notes I am saying "potential".

Examples below.

The first image is a 600 kHz wide shot centered on 14700 kHz.  Often I have more sweepers than this in this range, but you take what propagation gives you.  Note the two different sweepers near 14560 kHz.  This image was taken with the antenna pointed at 320 degrees true.




The next image was taken with identical settings, one minute after the one above, but with the antenna pointed 140 degrees true.  Note the sweepers near 14560 kHz are not seen, however another one with a different shape is seen around 14580 kHz.





This next image is a 1000 kHz wide shot centered on 28500 kHz.  The antenna is pointed 140 degrees true.  Note how many, and how strong, the sweepers are.





And the next image is the same 1000 kHz wide spectrum centered on 28500 kHz, however now taken with the antenna pointed 320 degrees true.  Notice how many fewer sweepers are seen, and some of the ones that are seen are different from the 140 degree shot.




So for me, at this time, it looks like the strongest 10 meter sweepers are from the south east, and the strongest 20'ish meter sweepers are from the north west.  It appears to have been that way for the last 6+ hours.

T!

[ChrisSmolinski]

24 MHz is quite active at around 1320z.
16 MHz is also busy.

[Token]

40 minutes after my post last night, with 4 pictures from 2 directions, 10 meters to the east closed down, and Asian stations started rolling in on 10 meters.  Then the sweepers from the north west on 10 really started coming in.

1.6 MHz wide span centered on 29240 kHz, antenna pointed 320 degrees true.  This is towards China for me, although naturally there are other nations along the same bearing.



A larger, and more detailed, shot of the above is here:
http://www.pbase.com/token/image/158277017/original.jpg

T!

[Token]

OK, no doubt, two Sundays in a row now there has been SIGNIFICANTLY reduced sweeper activity on Sunday vs any other day of the week.  I did not notice any particular reduction on Saturday.

To check the activity for the last week I have been recording a 1 MHz wide piece of spectrum, centered on 28500 kHz, every day at 1702 UTC.  Last Sunday and this Sunday there was greatly reduced sweeper traffic in this range.

The image below is the week day with the least amount of sweeper activity, the lowest count per minute of sweepers in 1 MHz during the recorded minute.  This was Friday morning.  Note that in this one minute time there are over 80 sweepers seen, typically on weekdays at this time I am seeing between 80 and 140 sweepers per minute.



A larger version of this image, more detail, can be seen here:
http://www.pbase.com/token/image/158330176/original.jpg


This morning in the same one minute period (1702 UTC, 28500 kHz center frequency, 1 MHz total width) I saw 6 sweepers in one minute.  Unfortunately the recording was corrupted for some reason (DOH!) so I had to remake it, and I did not do that until 2043 UTC.  So the image below is form 2043 UTC, not 1702 UTC.  However, it actually shows more sweepers than I saw at 1702 UTC when I counted them live.  This one has 9 or 10 visible.



Larger version of this image here:
http://www.pbase.com/token/image/158330280/original.jpg


On the surface of things I would say whatever generates the sweepers is an activity that is greatly reduced on Sundays.  That would argue strongly against natural phenomena, since few of them take Sundays off

T!

[OldSeaRock]

40 minutes after my post last night, with 4 pictures from 2 directions, 10 meters to the east closed down, and Asian stations started rolling in on 10 meters.  Then the sweepers from the north west on 10 really started coming in.

1.6 MHz wide span centered on 29240 kHz, antenna pointed 320 degrees true.  This is towards China for me, although naturally there are other nations along the same bearing.

If I'd have seen that before seeing it here, I'd probably have fallen out of my chair.  Never seen anything like it on my SDR.   

[jcwilshire]

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.