The AM Forum

So will the woodpecker by back?  The Russians are turning this one on soon, if not already.  The article goes back to  March.

https://www.defenseworld.net/news/26549/Russia_to_Deploy_New_Radar_to_Monitor_Aerial_Threats_Over_Entire_Europe#.Xv_S6ppJHX4

It will be interesting to see if it's on the ham bands and what the response might be. IIRC some people had played with the old one, sending strings of dits or random pulses back. Not saying it was a good idea.

One has been operating since December of 2019.

Heard anything new pecking in the bands?

--Shane
KD6VXI

"No", the Woodpecker radar is not returning.  It was a system deployed 45 years ago and shut down around 1990. 

The Konteiner HF system has been on the air for months. 

The Rezonans-N radar is VHF and should be no factor on US ham bands.

Here is the archive for the IARU Region 1 Monitor system monthly intruder reports.
https://www.iaru-r1.org/spectrum/monitoring-system/iarums-r1-newsletters/

Here are some screen shots from SigWiki showing some of the Konteiner OTH radar. emissions  The FM-on-pulse is quite a bit more sophisticated than the old Woodpecker, and probably does a good job of resisting dit strings that some of us used to send back and chase them around the bands in decades past. 
https://www.sigidwiki.com/wiki/29B6_%27Kontayner%27_OTH_Radar
The Region One IARU Intruder Watch has done a good job of identifying various rascals over the years.  It's one thing to note time and frequency, but actual ID of the signal takes some sleuthing, and they come through with the goods.  Here in Region Two, there are a few folks in South America who have attempted to do some work off and on, but without the success of the European group.    I'm surprised that the ARRRL hasn't showed much interest in taking the lead on Intruder Watch in our region.  With so many people having SDR receivers, the whole process of IDing signals is more efficient. 
73 de Norm W1ITT

What attracted my interest is that it is basically in Europe (near Poland).  It is reported to go as low as 3 MHz.  Unknown power levels, but the Russians are not shy when it comes to megawatts.  8)

I sometimes hear people making fun of Russian technology. It's a mistake. They make pretty good military-industrial stuff.

Yep, you can put Eccosorb on the aircraft skin and angle the surfaces for the 10 GHz radar, but you can't hide the fundamental 1/2 wave dipole resonances of the airframe at ~ 4 - 8 MHz.  And the Ruskies never abandoned the VHF radar as we did at the end of WWII.

The US Navy has maintained a UHF radar capability with the E-2D Hawkeye Airborne Early Warning aircraft since 1962.  It operates in the 400Mhz band.

Correct and they have redeveloped their VHF search radars attempting to locate stealth targets.  But the engagement (tied to SAMs, AAA, etc) radars are still microwave band(s) systems.

Some background on the old OTH, excerpts from https://www.chernobyl.one/duga-1-radar-station/
Many photos of the abandoned facility on that website.
I don't recall knowing that the Russian Woodpecker went off the air because of the Chernobyl disaster.

DUGA-1 RADAR STATION

Duga-1 is one of the three Soviet ‘over the horizon’ radar stations. A system made for early detection of attacks by ballistic rockets. This radar system was developed in the Soviet Union in the 1950s, during the cold war. The array station was hidden in a forest together with the secret military town Chernobyl-2.

In Soviet countries, all the secret military objects were named after the neighboring cities. Probably the military tried to confuse enemy intelligence this way. Chernobyl-2 was home for families of military personnel that worked at the radar site. The infrastructure of the secret town consisted of two parts. Firstly the Soviet over-the-horizon radar system Duga-1. Secondly the town for military personnel and their family.

Russian Woodpecker

The array was put into use at the end of May 1982. Its systems were extremely powerful, over 10 MW in some cases. It broadcasted in the shortwave radio bands. They appeared without warning, sounding like a sharp, repetitive tapping noise, which led to it being nicknamed by shortwave listeners as ‘Russian Woodpecker’. The random frequency hops disrupted legitimate broadcast, amateur radio, commercial aviation communications, utility transmissions, and resulted in thousands of complaints by many countries worldwide.

A Transmitter and a Receiver

The Duga-1 consisted of two sites, Chernobyl-2 and Lyubech-1, not far from the town of Chernihiv. The two transmitting antennas were located in Liubech and the two receiving antennas, here in Chernobyl-2. Because of different ways of counting the installations and the secrecy that surrounded them the radar is quite frequently, but incorrectly referred to as Duga-3, when in fact Duga-3 was never constructed.

Until 1985, the Duga was undergoing a series of improvements. In 1986, the radar installation was completely improved and began to undergo a state inspection. No one knows whether it would be possible for developers to bring the system to perfection or not, everything changed on April 26, 1986. (The day of the reactor disaster.)

Duga today

The entire population of the town was hastily evacuated from the radioactive disaster zone a day after the Chernobyl disaster. In this case the site was on stand-by for over a year, until it became clear that the operation of the radar in an environmental disaster was impossible. Today, the site is still abandoned and only visited by the guard and tourists. The radar in Lyubech was demolished in 2000.

There is a (somewhat conspiracy based) show on iirc Netflix called Chernobyl.  It may be Showtime.

It shows quite a bit of footage that can showcase the system.

It also supposes that Chernobyl was a sabotage because Duga 1 wasn't going to meet specification.  This created a problem for the guy running it, as a waste of soviet dollars was grounds for a death sentence.  He supposes that instead they melted Chernobyl down to hide this fact.

It's a good watch, even if somewhat (possibly) far fetched

--Shane
KD6VXI

Attached is a study of the F111 resonances from a Microwave Devices & Radar LECTURE NOTES VOLUME IV by Professor David Jenn.

Looks like 5.5 MHz for the main resonance. The previous slide in the lecture shows the wings are spread out.

F111 from wikipedia:
•   Length: 73 ft 6 in (22.40 m)
•   Wingspan: 63 ft (19 m)
•   Lower wingspan: 32 ft (9.8 m) swept
 - -- -
However you don't have to target the resonant frequency of the airframe, the plane will reflect energy any where in the HF spectrum.  The HF radar's advantage is the long range and the reflected waves from the ionosphere being able to see low-flying aircraft.