What is that roaring sound on shortwave ?

What is that roaring sound like an aeroplane engine on shortwave ?
Find our here.

The website I refer to with technical information is:

(note - STANAG one N not two :)

[patrickwall]

The roar when they're not carrying info is probably a frequency occupier.

[electrolytics]

No kidding? I always thought that was the refrigerator blasting out RFI or a transformer on the telephone pole outside.
Rock and Roll...great content as always.

[numberstation]

So that’s what the bugger is! Like you, I’d been wondering for decades. Thanks for clearing that up.

[abacus]

'HMOI-The Ultimate radio mystery' (by the VHSvLog youtube) at 6.19mins the background noise only. Also on youtube 'Night of the Cicadas singing' is very close in sound/pitch/tone. I wonder if signal tones similar to these youtube videoe might also be 'NATO signals STANNAG 4285 '? Are the HAVANA SYNDROME signal sounds also NATO Military Forces?

[thespaceinsidemyhead]

I've often heard this and wondered what it was. Thanks for the explanation

[rEdf]

In the 70's and 80's STANAGs (or Buzzsaws as they were called) used to buzz at around 165 Hz similar to the sustained sitar tone in the classic Canned Heat blues tune, Im On The Road Again. in fact in the 1980's I played that song on my guitar to those sounds.

[vitofish]

Sounded like a ships engine room for 60 years thanks

[lenzotrumpet]

I listened to SW radio. Since I was about ten years old I alway wondered what that buzzing sound was ...It took me 61 years to find out...I used to love to pick up utility stations and their was recorded radio station that would send out test signals from exotic places.

[RJDA.Dakota]

I have always wondered what that was. Interesting content. Love your channel and videos.

[snowpuppy]

Appreciate your clearing that up. New subscriber.

[RadioWhiz]

Thank you i get those sounds all the time they are stong Signals

[canadianradiotvguy]

You Deserve More Subs! You Got Great sense of humour! 73s!

[bill-]

I hear these noises and wondered what they are. There's lots of them.
I wondered if they had replaced the numbers stations.
Thanks for the info. and clearing it up.

[Ploggy.]

Wow thanks for the info Peter I’ve always wondered what that was and thanks for the link too 📻👍

[dominicrivron]

I've wondered what this sound was myself for decades, too. I used to pick it up on shortwave radios when I was kid. A colleague of my dad's, who was a radio ham, told me it was coming from Jupiter. I think there may have been all sorts of myths about it. I thought it might be something to do with alternators generating AC electricity. I even logged all the frequencies I could find it on, to try and find some sort of harmonic relation, to no avail. Now I know!

[ArclampSDR]

you can use a radio program called sorcerer to decode it (but not decrypt)

[batica]

There is a program to try and decode it, called Sigmira. I managed a few times to get an plaintext message preamble from some French station, but most of the traffic is of course encrypted.

[stephenwilliams]

Lived thrugh the cold war. Jambing was the thing. . I learned to filter and some times got around the noise.

[DerekWitt]

I’ve wondered about that. Seems like I hear it more in the upper bands (~15-25 MHz) lately. I thought it was EM interference from the electrical substation across the street from me or something.

[simmo]

I always thought it was some sort of nearby interference. Didn't realise it was military communications.