Mysterious CW Transmissions

[teekay99]

Just reporting on an interesting oddity:
The chatter-verse on the University of Twente Web SDR is talking about a series of CW beeps occurring in 400 kHz intervals from 5000 kHz clean through 30000 kHz. The transmission consists of a beep heard in nearly 1 second intervals, apparently synchronized using the same cadence and rhythm across all frequencies on which it is broadcast. Rudimentary "triangulation" by chatters using multiple web SDRs suggest the source might be originating from Southern Europe.

It's just weird.

 

[Incognito]

I'm dense. What does all that mean Aliens or something terrestrial

 

[Friendly Engineer]

I'm dense. What does all that mean Aliens or something terrestrial

 

[Friendly Engineer]

Probably some radio amateurs playing around.

 

[teekay99]

I'm dense. What does all that mean Aliens or something terrestrial

No one has provided a good explanation yet. My theory was that it was a homebrew transmitter that is generating a square wave and throwing harmonics. But as someone rightfully pointed out, if that were the case, there would be a 10 dB signal level drop on each harmonic. I've not observed that 10 dB signal strength drop on each 400 kHz interval, so that kills my theory.

 

[teekay99]

Probably some radio amateurs playing around.

I thought about that too. It's very plausible since amateurs pull these kinds of stunts regularly. But given such a wide spectrum in which this is occurring, if it is amateurs, they have done a great job synchronizing their work effort.

 

[twinturbo]

If you're hearing a "beep" (and you're not providing a beat modulation) it's not CW. You wouldn't hear anything on true CW.

But yeah much (although not all) of that range is ham bands. I'm not aware of that particular activity but I can't do much on HF where I live.

And hi everyone, I think this is my first public post. I mostly just lurk. Great site though with a lot of useful info and good people!

 

[Friendly Engineer]

If you're hearing a "beep" (and you're not providing a beat modulation) it's not CW. You wouldn't hear anything on true CW.

But yeah much (although not all) of that range is ham bands. I'm not aware of that particular activity but I can't do much on HF where I live.

And hi everyone, I think this is my first public post. I mostly just lurk. Great site though with a lot of useful info and good people!

Thanks for posting! Hi!

 

[twinturbo]

Also had a passing thought of OTH radar (think "Russian Woodpecker") but the modulation doesn't seem correct and the pulse rate is all wrong, way too low. That's really bad resolution for detecting inbounds.

 

[teekay99]

If you're hearing a "beep" (and you're not providing a beat modulation) it's not CW. You wouldn't hear anything on true CW.

But yeah much (although not all) of that range is ham bands. I'm not aware of that particular activity but I can't do much on HF where I live.

And hi everyone, I think this is my first public post. I mostly just lurk. Great site though with a lot of useful info and good people!

Yes good point. I used the term "beep" for simplicity. But yes, it could be periodic closing of a CW transmitter circuit causing a brief carrier wave to be transmitted. And on the University of Twente Web SDR, you do have to be in CW mode to hear it as a "beep". In standard AM mode, it's more of a "click".

And welcome to the board and contributing the the conversation!

 

[expat42451]

Could it be some sort of new beacon to assist in determining propagation? No 10 db drop in each successive higher freq could indicate its intentional.

 

[teekay99]

Could it be some sort of new beacon to assist in determining propagation? No 10 db drop in each successive higher freq could indicate its intentional.

Perhaps. Some of the transmissions are occurring in broadcast bands, such as the 49M, 41M, or 31M band.... So who ever is doing this, they do not care about disrupting those licensed to broadcast in their respective bands...

 

[twinturbo]

Perhaps. Some of the transmissions are occurring in broadcast bands, such as the 49M, 41M, or 31M band.... So who ever is doing this, they do not care about disrupting those licensed to broadcast in their respective bands...

And right there you can eliminate ham radio as the source because ham operators don't act like that. It would have to be someone who has no concern about world radio agreements and treaties. I doubt very much that it's any kind of broadcaster, and certainly not hams.

 

[william]

Also had a passing thought of OTH radar (think "Russian Woodpecker") but the modulation doesn't seem correct and the pulse rate is all wrong, way too low. That's really bad resolution for detecting inbounds.

Sounds like you know what you're talking about. Were you or are you military?

Welcome, nice to meet you.

 

[twinturbo]

You're very kind, William. I'm just a lifelong study of all things in that area. I claim no special knowledge that I'm ready to mention on here, I just try to learn what I can. I have nothing but the utmost respect for all who stand to defend our freedom.

Thank you for your many excellent posts as well by the way. There are several of you I respect very highly, you are once of then. Your posts are always well considered.

 

[WSSF]

Encoded Digital Burst?

 

[william]

You're very kind, William. I'm just a lifelong study of all things in that area. I claim no special knowledge that I'm ready to mention on here, I just try to learn what I can. I have nothing but the utmost respect for all who stand to defend our freedom.

Thank you for your many excellent posts as well by the way. There are several of you I respect very highly, you are once of then. Your posts are always well considered.

Thank you.