OT - Over-the-Horizon Radars Raising the Ire of European Monitoring Systems

From The ARRL Letter for February 28, 2019

Over-the-Horizon Radars Raising the Ire of European Monitoring Systems

The January issue of the IARU Region 1 Monitoring System (IARUMS) newsletter reports the Russian "Sunflower" coastal radar, located east of Vladivostok, is being heard at nights on 3,716 kHz and 6,860 - 7,005 kHz, as well as on several

60-meter frequencies. A Chinese wideband over-the-horizon (OTH) radar also appeared on 7,000 kHz in early January.

Waveform of a Chinese OTH radar on 7 MHZ. [Photo courtesy of Wolf Hadel, DK2OM]

"Once again we have problems with short-wave radars," said the Deutscher Amateur Radio Club (DARC) Monitoring System. DARC is Germany's IARU member-society. "The Russian coastal radar 'Sunflower' transmits on almost every evening at 5,310 -

5,410 kHz. As a result, our new mini-band is useless." DARC was referring to the narrow worldwide allocation of 5,351.5 - 5,366.5 kHz to the Amateur Service on a secondary basis by World Radiocommunication Conference 2015 (WRC-15). It said the interference appears as a deep hum. The Sunflower radar employs Frequency Modulation on Pulse (FMOP) at 43 sweeps per second to detect aircraft and, over water, vessels.

DARC continued, "The system is so successful that the Chinese operate several 'sunflowers' on the east coast. Chinese OTHs work almost daily in the 20-meter band. In the mornings, we can often receive them with high field strengths." DARC said the Chinese OTHs cause worse interference than the Russian radars.

DARC mentioned other OTH radars operating on 40 meters: "At the moment we have extreme problems with the 'Container' radar from Russia." IARUMS has often reported problems from this radar.

In December, IARUMS reported an OTH radar active on 21,170 kHz from the Sovereign Base areas of Akrotiri and Dhekelia, a British Overseas Territory on the island of Cyprus.

While 60 meters and 80/75 meters are shared bands, the 7,000 - 7,200 kHz segment of 40 meters is allocated exclusively to the Amateur Radio Service worldwide. Some domestic Amateur Radio HF allocations outside Region 2 (the Americas), such as 7,200 to 7,300 kHz, are either shared with other services or not available to radio amateurs. On HF allocations such as 30 and 60 meters, Amateur Radio is secondary to other users. The 20-, 17-, 15-, 12-, and 10-meter bands are exclusively available to the Amateur Radio Service worldwide.

Reply to
gray_wolf
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Any links where we can learn more?

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Reply to
Winfield Hill

There is also the Australian Jindalee HF radar network. There are some cool satellite pics of the sites.

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John Larkin         Highland Technology, Inc 

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Reply to
John Larkin

So they build a bajillion dollar defense radar but it only goes on almost every evening? Like they just don't turn it on sometimes? Well if you're going to invade then those are the times I guess

Reply to
bitrex

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Reply to
Gerhard Hoffmann

"Woodpecker" V2.O

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Reply to
Cursitor Doom

Not possible, especially from Vladivostok, which is near Japan. This radar has a range of only 300-400 km. It's a surface wave OTH, not an ionospheric bounce.

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Reply to
bloggs.fredbloggs.fred

Yep:

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Scroll down a bit for the article. Lots of stuff there.

Reply to
gray_wolf

s

There's an article on Wiki:

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Reply to
gray_wolf

And you can use websdr.org to select a site to listen..

Cheers

Reply to
Martin Riddle

They're frequency-agile, or I hope they are (they have been since at least the days of the Russian Woodpecker, DUGA-3). It's not that they're on and off, it's that they're trampling important (internationally reserved) frequencies at those times.

Tim

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Reply to
Tim Williams

I would think such a radar would be strategically useless as it should be easy for a nation state to SPOOF a return signal and make it look like the return is coming from anywhere the spoofer wishes. m

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Reply to
makolber

They don't publish a whole lot about this one, it looks flimsy, hit translate button:

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Under main tactical and technical characteristics they list 30 minute recovery time. Just exactly wtf is that? Must be a translation issue.

Under the detection of aerial objects, it won't see a real threat until it's too late for them. I mean do they think nobody knows where this site is and isn't going to shoot something at it from low altitude.

This is a poor man's radar, nothing to brag about. All they wanted to do was publicize the ability to detect F-35s, or so they claim, to make U.S. look foolish for spending $1.5T.

Reply to
bloggs.fredbloggs.fred

The array points north. Care to guess why?

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Reply to
John Larkin

Keep the sun out of its eyes?

If the radar is "pointing" at the water in the picture, then the Vladivostok radar is looking at the Sea of Japan, which is more to the southeast.

Reply to
bloggs.fredbloggs.fred

How would they?

If it's got a unique code on every pulse, it's arbitrarily hard to guess, beforehand, what that code is. (At best, if they use a PRNG, it could be predicted, but that would also be easily obfuscated as well.)

Or if the jammer is very close, giving ample time to merely delay the return, it will be coming from an obviously nearby location -- these arrays have lots of directionality in both X and Y.

Tim

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Reply to
Tim Williams

Against a single receiver OTHR, this may work especially if the spoofer also does some frequency shifting to simulate virtual target doppler. OTOH, an OTHR with multiple receivers at different sites will show a real target consistently in the same place and movement, but a spoofed target will show different locations and different motion vectors on different receivers.

Reply to
upsidedown

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