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Down Under
Mystery QRM Signals being transmitted to Australia
2005-06-28
In Australia two very strong pulse signals are appearing on HF amateur bands and the hunt is on to determine the source of these intruders. A radar like pulse which peaks at 10dB over signal strength 9, and reported to be up 100kHz wide is being heard regularly 7020-7080 kHz in the (VK) mornings and 3590-3800 kHz in the (VK) evenings. Reports from VK and ZL point to it being north-west of Australia. JAÂŽs and WÂŽs during QSOs with VK also say they can detect the signal but at a lower strength. ItÂŽs an unwelcome reminder of the havoc caused by the over-the-horizon radar dubbed the Russian Woodpecker that fired up in 1976 and lasted a decade. Hopefully this latest pulse signal is not another OTHR.

A repetitive cyclic sounding pulse signal is also being experienced in VK on most amateur HF bands and often simultaneously on more than one band. An inquiry by the Wireless Institute of Australia (WIA) has received assurances that neither the (JORN) Jindalee over-the-horizon Defence radar in central Australia or a new SECAR system in the Torres Strait north of Queensland are to blame.
The (SECAR) Surface wave Extended Coastal Area Radar has begun trials. It will enhance the monitoring ability for Defence and Customs to detect illegal fishing and immigration. It could also be developed to provide early storm warnings. With JORN and SECAR being given alibis, the WIAÂŽs Intruder Watch intruders@wia.org.au is now seeking reports from radio amateurs on the harmful interference.

In particular it needs directional information and reported incidents of these intruders disrupting QSOs and causing harmful interference. The WIA will then take the matter up with the Australian Communications Authority for its investigation.
Posted by:Spavirt Pheng6042

#16  Its Yamamoto and the PLAN Pearl Harbor Striking Force.
Posted by: JosephMendiola   2005-06-28 23:48  

#15  The Indian National Mesopheric/Troposphere/Stratosphere Radar

The scientific requirements dictated that the Indian MST Radar should be located preferably below 15 degrees North latitude. Hence after careful consideration of the various constraints, a site at Gadanki Village, near the temple town of Tirupati in the Chitoor district of Andhra Pradesh was selected for locating the Indian MST Radar . NMRF is located off the Chitoor -Tirupati main road in a picturesque landscape spreading over an area of about 42 acres.


System
The Indian MST Radar is a highly sensitive VHF phased array radar operating at 53 MHz with an peak power aperture product of 3 x 1010 Wm 2. The system design specifications, including that of the intermediate stage of ST mode , are presented below :

The phased array consists of 1024 crossed three-element Yagi antennas occupying an area of 130m x 130m. It generates a radiation pattern with a main beam of 3 deg , gain of 36 dB and a side lobe level of -20 dB.The main beam can, in principle, be positioned at 82 different look angles in NS and EW plane.
A total transmiting power of 2.5 MW ( peak ) is provided by 32 transmitters ranging in power from 20 kW to 120 kW, each feeding a subarray of 32 Yagis. To achieve the desired low side lobe level to the adiation pattern, the power is tapered across the array according to a modified Taylor distribution. The required power taper is accomplished in one principal direction by the differential powers of the transmitters and in the other direction by the series feed network.


Posted by: Atomic Conspiracy   2005-06-28 22:03  

#14  the synchronized brainwave flatline buzz from all the madrassahs
Posted by: Frank G   2005-06-28 21:57  

#13  India
Posted by: Atomic Conspiracy   2005-06-28 21:48  

#12  Whoa, there, mojo. The article says 7000 kHz, not 7000 MHz. That's down in the 40 meter ham band (and 80 meter for the other). I don't know if there is any radar that ever went that low. You'd need a pretty big antenna. The original Chain Home system (Battle of Britain) was something like 30 MHz and that had huge towers.

Maybe it's a typo and they really mean 3.5 and 7 GHz, but they also mention interference on other amateur HF bands. (HF is 3 MHz to 30 MHz).
Posted by: Jackal   2005-06-28 18:30  

#11  NW of Australia points to India, or possibly the Chinese naval base in Myanmar.
Posted by: phil_b   2005-06-28 17:51  

#10  ELNOT Electronic Intelligence Notation

(Acronym Finder)
Posted by: SwissTex   2005-06-28 17:02  

#9  Radar pulses at ~7 and 3.5 GHz? The 3.5 gig freq is close to resonant for water (2.45 gig last I heard), which might make it a poorly-designed weather radar, but 7 gig? And different in AM and PM? Wierd with a beard.

Triangulation ought to pinpoint the source.
Posted by: mojo   2005-06-28 16:07  

#8  ELNOT
Elvis Lives Northwest Of Time
Posted by: Woodpecker Lips   2005-06-28 12:52  

#7  BTW - he didn't make profits or have any connection with those who made the profits.
Posted by: 3dc   2005-06-28 11:46  

#6  what is a ELNOT?
Posted by: 3dc   2005-06-28 11:28  

#5  Post the ELNOT so all the classified geeks here can look it up.
Posted by: OldSpook   2005-06-28 11:20  

#4  Hey - careful
A buddy invented and deployed the Woodpecker - then defected. His efforts made huge profits for those selling special filters to remove it from received signals.
He's been a productive member of US society since about 1975.
It was fun introducing him to a PavePaws designer.
Posted by: 3dc   2005-06-28 10:48  

#3  Hmmm .... who is northwest of Australia and bought Soviet military technology which they're working hard to improve and deploy??
Posted by: anon   2005-06-28 09:36  

#2  Isn't this the plot on "Lost"?
Posted by: tu3031   2005-06-28 09:34  

#1  Could someone translate the radio-geek terminology into Common Speech for us?
Posted by: Mike   2005-06-28 09:31  

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