Woodpecker sound in DX Land

[9C1Driver]

I'm sure many of you have heard this sound in the freeband channels above cb 40. So what is the deal with this sound and where does it come from? Your thoughts?

 

[w9cll]

OTH radar?

 

[Shockwave]

When DX rolls in from the southern US I hear an interesting wideband signal every 40 KHz or 4 channels. It covers well over 1 Mhz. of spectrum and makes a repetitive sound something like "vavervavarump" at about a 1.5 second interval over and over for hours. It almost sounds like some alien transmission but it's probably an induction RF heating unit or plasma torch many states away with an RF leak. Although, OTH radar is not impossible since the pulses seem like the right duration.

 

[Captain Kilowatt]

It could be OTH radar however the newer systems do not sound like the old Russian woodpecker of the 80's. Google Chinese Dragon radar and look for a sound byte. That seems to be the one OTH radar most people hear nowadays. Generally OTH radar sweeps across the band BTW and does not stay put.

 

[M0GVZ]

Radar. Been seeing it on 17m and 20m as well.

 

[Lil'Yeshua]

This?
QRM radar QTH DIVISION 50 - YouTube

 

[Captain Kilowatt]

Or this.

https://www.youtube.com/watch?v=0qCfUUF6EBI

 

[Road Squawker]

Or this.

https://www.youtube.com/watch?v=0qCfUUF6EBI

DAYUM,............... I don't believe I listen to the whole thing:headbang

 

[Lil'Yeshua]

DAYUM,............... I don't believe I listen to the whole thing:headbang

So,what kind of info is being transmitted you think?

 

[Captain Kilowatt]

So,what kind of info is being transmitted you think?

It's radar. Pulse goes out hits something and bounces back to the receiver. The pulses have to be timed so the transmitter is off when the receiver is on basically. There may be something embedded but it would be of no consequence for interception and would be encrypted anyway.

How Radar Works

 

[space cowboy]

There may be something embedded but it would be of no consequence for interception and would be encrypted anyway.

if it's of no consequence, why then encrypt it?:glare:

 

[9C1Driver]

Or this.

https://www.youtube.com/watch?v=0qCfUUF6EBI

Yup this sounds just like it.

 

[the_old_curmudgeon]

if it's of no consequence, why then encrypt it?:glare:

so that everyone else expends resources to try to crack the encryption so they can make sure that it is of no consequence?

 

[Captain Kilowatt]

if it's of no consequence, why then encrypt it?:glare:

Signal identifier so the receiver can lock on to the signal despite interference. If someone decoded it they could send a signal back effectively jamming it. The old Soviet OTH Woodpecker radar could be forced to move off frequency if a series of dots were sent in CW at the proper speed. Things have come a long way since then.

And by no consequence I meant to the regular listener.