The Loud Digital Noise on 3870 DF'ed

[K1JJ]

There have been many complaints about the loud digital noise on 3870.  At night it can get pretty intense, especially for the east coast AMers hanging on 3875..

Last week I did a DF on it using my NE / SW loops and determined it is definately coming from NE.... possibly eastern Canada or Europe.

Last night I decided to find out just how far away it was.  On 75M it's a simple matter of watching for the signal to peak sharply during it's grayline sunrise and then start to dive over a 30 minute period.  It did just that last night. I had it in the background and saw it peak sharply to S9 + 40 over at about 3 AM east coast.  It then was down 20 dB by 3:30 AM and continued to fall as I went to sleep.  

The  grayline sunrise occurs in extreme western UK, possibly Ireland, at about 3 AM east coast.  It also does in the Canary Islands off Spain.  My guess is it is a western UK station, right on the ocean, beaming USA. Probably military data use, but again, just a guess..

The way to get closer is have someone with global receiver access check it out. That shud pinpoint it further. Then just hope it goes away...   There's a number of these from Eu up and down the 75M band.

T

[K1JJ]

Doing a quick check, there are almost identical telemetry-type signals to the 3870 one on 3820, 3859, 3915, 3962 and 3967... ALL from Europe and presently all about S9 +20.

Three more on 3550, 4045 and 4057.  That's about it.

I remember before the Gulf War in 1990 the band was suddenly filled with stuff like this.


Hmmm... I wonder if they are related to some central purpose?  These things have been on and off for a long time, but I'm not sure if as numerous as now.

T

[WA3VJB]

That's quite a tally.  Almost like Radio Moscow every 10Kc during the Cold War.

So do you believe a U.K. or European-based remote receiver might affirm the location during daytime condx?

There are a mess of nodes on globaltuners website, with maybe a half dozen up and running at any given time.

You can actually "see" the receiver list without enrolling or logging in.  That's how I compiled the U.K. nodes below.

Let me know when/where to listen if I can help.

[steve_qix]

That digital signal on 3870 is SUPER loud here at my place at night.  The fact that it is so strong here in the north-east, strongly suggested a European origin right along.  It's good to have this confirmed.

I'm wondering out loud if there is some "official" action that might be taken.  These signals will render a frequency pretty much unusable, at least in this part of the country.  Things could get like 40 meters - can't use the band after a certain time due to foreign intruders.

[kb3ouk]

http://websdr.ewi.utwente.nl:8901/

Based in the Netherlands. Right now, 3870 is weak (around S8); nothing on 3820, 3859, 3915, 3962, 3967, 4057, or 3550; 4045 is coming in at S9+20. 3870 and 4045 sound to me like a DRM signal.

[W3RSW]

Well, look at this one on 40 meters just now.  7120 to 7200 +/-

Screen shot shows date and time.
Very broad and heard one LSB qso in the middle of it wonder what the strange intererence was.  Don't think they had the advantage of seeing just how wide a span the signal covered.  In the limited SSB bandwidth I heard, it sounded like a chuffing at about 5cps, each chuf a 'white' noise sounding, proably at a high digital data rate.

Israelies about ready? Hmmm.
Or the "Independence Day" moon sized saucer just hanging around pre-invasion.  Woooo.

[Pete, WA2CWA]

That digital signal on 3870 is SUPER loud here at my place at night.  The fact that it is so strong here in the north-east, strongly suggested a European origin right along.  It's good to have this confirmed.

I'm wondering out loud if there is some "official" action that might be taken.  These signals will render a frequency pretty much unusable, at least in this part of the country.  Things could get like 40 meters - can't use the band after a certain time due to foreign intruders.

http://www.arrl.org/intruder-watch

The International Amateur Radio Union Region 1 is a federation of national associations of radio amateurs from Europe, Africa, Middle East and Northern Asia.

And, the 80 meter band plan for Region 1:

                   MAX   Preferred Mode and Usage
                    BW
3500 - 3510  200  CW, priority for intercontinental operation

3510 - 3560  200  CW, contest preferred, 3555 kHz - QRS Centre of Activity

3560 - 3580  200  CW, 3560 kHz - QRP Centre of Activity

3580 - 3590  500  Narrow band modes - digimodes

3590 - 3600  500  Narrow band modes - digimodes, automatically controlled data stations (unattended)

3600 - 3620  2700  All modes - digimodes, automatically controlled data station (unattended), (*)

3600 - 3650  2700  All modes, 3630 kHz - Digital Voice Centre of Activity, SSB contest preferred, (*)

3650 - 3700  2700  All modes, 3690 kHz - SSB QRP Centre of Activity

3700 - 3800  2700  All modes, SSB contest preferred,

                   3735 kHz - Image Centre of Activity                   

                   3760 kHz - Region 1 Emergency Centre of Activity

                   3775 - 3800  2700 All modes, priority for intercontinental operation

[WBear2GCR]

I thought that SDR has a DRM decoder built in?

Also on Global Tuners, there are receivers all over the world you can use and check...
some are very good, some terrible, but all over the world.

                   _-_-

[K1JJ]

http://websdr.ewi.utwente.nl:8901/

Based in the Netherlands. Right now, 3870 is weak (around S8); nothing on 3820, 3859, 3915, 3962, 3967, 4057, or 3550; 4045 is coming in at S9+20. 3870 and 4045 sound to me like a DRM signal.

Yep, that's how to do it!

When you took that S9+20 reading on 4045, it was about 1 PM in the afternoon over there. Depending on their antenna beam direction and power , I'll bet that station is within 200 miles of your global tuner, maybe even closer.  

If the 3870 antenna is beaming USA and on the ocean, then the Neatherlands wud be behind the array. Maybe that's why the 3870 station is only S8.

The 4045 station, which I didn't check for sunrise longitude, could be closer to the Neatherlands...

But, who knows if the remaining stations are too far away to hear or just off the air at this time. Searching a few more Global Receivers over a period of time will give us a pattern.

Good job.

T

[kb3ouk]

Same receiver right now
3550: S7, this one was interesting, would transmit for a while, drop out for a second or two, come back on with a second long blast of tones then start transmitting again
3820: at S8-S9
3859: nothing here, but at 3857 there's a digital signal at S9+10
3870: S9+10
3915: S8
3962/3967: This one is even more interesting, there's a AM signal on 3965 at 20 over, but then you can here the digital hash underneath it. Looking at the waterfall it appears as if the AM and digital are coming from the same transmitter??? Digital and AM are both centered on 3965, the AM appears to be 5 khz wide and the digital is 10 khz wide, takes up everything from 3960 to 3970
4045: S9+30
4057: S9+20

[K1JJ]

It about 5:30 PM local over there and the sunset grayline is starting.  The signals you see that are starting to really come up are probably farther east, like the 4045 and 4057 signals that are already S9 + 20, +30. Might be in darkness, showing it might be a few hundred miles east of the ocean in Europe.   The others seem still in daylight.  Unless we are behind their directive arrays. We'll have to see if they peak up too.

If you took the time to watch when each one suddenly jumped up in strength, you could get a good take on their E-W longitude.

I have a grayline chart that (DX Atlas software) that shows sunset / sunrise.


** BTW, I just took a quick listen on the NE Beverge and NE loops at 190' and hear none of these signals. It shows that they are definately not in  eastern Canada - and definately in Eu.

T

[kb3ouk]

Right now on 3855 through the Netherlands receiver I have what sounds like a fax transmission going on over top of the DRM that was there. 3965 is a mess, the digital station left and now there's a AM broadcaster on there that is 40 khz wide. And some intermittent digital stuff just started on 3875.

[KG4DAG]

The AM broadcast is Radio Taiwan from Issoudun, France.  It may be jamming from China behind them.

[Steve - K4HX]

Heard that same signal this past Sunday Rick. It was loud when I beamed to the northeast and gone when beam southwest.

Well, look at this one on 40 meters just now.  7120 to 7200 +/-

Screen shot shows date and time.
Very broad and heard one LSB qso in the middle of it wonder what the strange intererence was.  Don't think they had the advantage of seeing just how wide a span the signal covered.  In the limited SSB bandwidth I heard, it sounded like a chuffing at about 5cps, each chuf a 'white' noise sounding, proably at a high digital data rate.

Israelies about ready? Hmmm.
Or the "Independence Day" moon sized saucer just hanging around pre-invasion.  Woooo.

[W3RSW]

It stopped about ten or so minutes after I 'captured' some of it Steve.
Definitely not local since more distant qso's mentioned it.

I guess your 40M dual loop must have switching to each loop?
Think you mentioned it in your yard setup not too long ago.

[Steve - K4HX]

Two loops A and B. A is fed. B is a reflector electrically lengthened with a coax stub. This connection beams Northeast. At the flick of a switch, B is fed and A becomes the reflector. This connection beams Southwest. Details at the link.

http://amfone.net/Amforum/index.php?topic=21534.0

[AMroo]

Why not just call up a cupla big tall ship type stations and get them to have a local AM QSO right over the top of it. If they cant communicate they will soon move.
Do unto others as they do unto you, especially if they are in our band in contravention of agreements.

[W3RSW]

If your talking about the 40 mtr. signals, multiple QSO's are already ongoing over top of them. Their very wide digital signal (with probable error correction of a type we can only imagine) expects interference from a relatively low power, small toothed service such as ours.  That's why they're on 40.

Looking at wide-band SDR displays of a megahertz or so shows numerous types of "non-traditional" signals such as sliders, frequency agile, wide band, very high speed stuff going on all the time.  I have no doubt that a lot of it occurs in our region, not just the fabled "Eastern European block."

[Steve - K4HX]

Those sigs on 80 (some on 160 too) that appear to be coming from EU sound a lot like the recording at the link below.

http://www.astrosurf.com/luxorion/Radio/mode-nato-stanag-4285-sending-crypto-msg.wav

[flintstone mop]

I thought that SDR has a DRM decoder built in?

Also on Global Tuners, there are receivers all over the world you can use and check...
some are very good, some terrible, but all over the world.

                   _-_-

Nope! I was disappointed too. Flex has the DRM filter. I bought...ya bought the license for a DRM decoder and the fidelity is out of this world. I have listened to New Zealand on 9870. Very little fading and FM-like audio. I think they use a Thomson 100KW digital transmitter. DRM is not big in the USA. That's why the deocders that are free, are un-assembled. You can donwload the components of the decoder and you need to know some computer magic for writing and building an executable program.
That's why I bought the package and license. Somewhere in Australia. $60USD and it plays as a third party software and uses the VAC feature of powersdr.
Short-wave is pretty dead here in the USA.
On the powerSDR panadapter a DRM signal looks like a very broad RF signal.


Fred

[flintstone mop]

Here is a view of a DRM signal on 9870...Radio New Zealand

[steve_qix]

So, is that digital signal on 3870 DRM? Has anyone with a DRM decoder tried it out with that particular signal?

[Steve - K4HX]

It's not DRM. DRM is much wider.

The signal on 3870 is only about 3 kHz and sound much like the audio at the link below.

http://www.astrosurf.com/luxorion/Radio/mode-nato-stanag-4285-sending-crypto-msg.wav

This is listed at a NATO STANAG encrypted modem. It could be PSK or QAM.

DRM is about 10 kHz wide. It is COFDM with each carrier using QAM. See the spectrum shot at the link below.  This is from 2005. The DRM is at the right end of the spectrum, 3990-4000 kHz.

http://amwindow.org/misc/gif/75m3apr05annotated.gif