Who knows what does this noise is? Strange noise heard on shortwave. 27mHz 11m

Noise heard at Brazil´s South-East at about 5 pm.
I´ve heard this noise for many years without identify what it really is.
Is that a kind of shortwave radar?
One characteristic is that it goes changing the frequency, few kilohertz each time.
I´ve tried to "decode" using a computer but it is not any of digital modes.

Sometimes it appear around 10 MHz, sometimes, 15mHz, this time it was on 27,97x mHz.

Category:

Science & Technology

Tags:

• Shortwave
• radio
• radar
• noise
• antenna
• amateur
• 27mHz
• 11m
• PX
• citizen
• band
• 40m
• Ham

[alotito]

HAARP uses frequencies between 2,8 e 10 MHz.

[mrmanxelmer]

Put in AM or FM - its 11m (CB) packet stations.

[alotito]

@mrmanxelmer CB dont transmits packet. Packet is a mode used by Amateur Radio. As other comments said, it is OTHR. Over The Horizon Radar. Note that the frequency changes.

[roolpeiniger]

This is OTHR!

The operation is between 27.000 and 29.950

Most operations were spotted between 27.400 and 28.400

The mystery on that opertions is the copy around the world

On a QSO with an station from canada he told me to have the OTHR with 5/9

At the same time here in germany i had the same 5/9

20 min later a station from texas told the same

another 30 mins later the same report from poland and russia

seems to be an radar network but wich country is still unknown

[alotito]

@roolpeiniger Many people is telling me it is in US. It is very interesting what you said because it is heard worldwide.

[toughcookie128]

Finally, I think it's the OTH radard in california: search in google for: SRI International then click on the company web site then Engineering systems link then the Over the horizon radar and you'll see the California OTH radar page. Wow, it's a 20MW transmitter.

[alotito]

@toughcookie128 I´ve found the site. Very good.

[BsoxFireCaphs]

it can be russian horizont radar

[mrmanxelmer]

Packet is NOT just used by Ham operators. Get packet software, build the box, wire up the radio and you can use anything to play Packet. Plenty of 27mhz activity using packet - plenty of packet activity on the Free to Air PMR as well. Try listening to a packet signal on vhf or uhf - and then switch to sideband.

[kristinloveschevys]

@alotito also, search "horizontal radar" on you tube. One should come up immediately with some sort of finnish othr if u want to hear what they sound like

[kristinloveschevys]

27.935 USGOV

27.940 94 AU MARITIME

27.945

27.950 95 PNG MARITIME/USGOV

27.955

27.960 96 AU MARITIME/USGOV

27.965 MARS

27.970 97 PNG MARITIME

27.975 MARS

[reddog694uk]

It's a dog barking !!

[endrizo]

HAARP ?