Tuesday, November 11, 2008

OTH Radar and the ASBM Threat



Feng said...

great work Sean.

Sean O'Connor said...

Thanks. I intended it to be an overview of worldwide OTH systems, but decided later to reduce the emphasis on most of the systems out there and severely cut back the Cold War bit to focus more on the Chinese ASBM aspect.

Anonymous said...

Hi Sean,

Congrats from Hungary!

You may add this as well:



satcom15 said...

Hi Sean,
Very interesting. However there is one Chinese facility not on your list. Check out these GE coords:

40°30'4.64"N 116° 1'46.59"E

Interestingly the snow covered ground image that really highlights the antenna field is not available in the History layer. I added a placemark last year that included an image. The image was removed from the place mark as well. However go to the thread associated with the placemark and download kmz file. Check out this GE community thread:


Here is the the kmz file:


You make me wonder if my place mark may be a transmit only site abd it could be tied to the receive site you identified. That could be one of three since a linear array typically only has 60 degrees in azimuth coverage. I'd like to know the site coordinates.

In my kmz file I show two semicirclular antenna arrays with the same orientation though one is broken into pieces while the other is a complete semicircle. One could be for transmit and the other for receive (see the text). On the other hand they could both be transmit sites with different operating characteristics and tied to a distant receive site. Improving accuracy with better signal processing makes me wonder about a dual transmission antenna capability for frequency, polarization, and/or space diversity as a means to improve accuracy - thus the two arcs. Alternatively, maybe you identified a transmit site and the facility I've placemarked is the receive site. This assumes that the two facilities are connected of course.

Regardless, its clear the Chinese have an active interest in HF radar sytems. Oh, BTW check out this curiosity at:

23°19'36.81"N 113° 5'6.72"E

Looks like a CDAA HF DF Site. But its the only one like it I've found. And I have no idea if in fact its that or something completely different.


John C said...

Hi Sean, Many thanks for very useful report on this subject. OTH-B in China does actually have a very long history going back to around 1967. There is a very useful report authored by Le-Wei Li in Radio Science, Vol 33, No 5, pages 1445~1458, Sep/Oct 1998, although it is a little vague on some of the site locations.

Agree with satcom15 that 40°30'4.64"N 116° 1'46.59"E is very interesting. 6 (six) antenna sites in a massive antenna farm arrangement around a central control facility. The sheer size and boresights are very interesting: 134º and 141º more or less bisecting the Japan - Philippines gap and 203º crossing near Hainan, over Malaysia and the Malacca Straits into the Indian Ocean tend to suggest submarine VLF broadcast faciliites - as a guess.

Anonymous said...

Provided by the "alt" image name of the OAO RTPR GRANIT website

53°59'1"N 43°50'44"E

is it an OTH radar Sean?

Sean O'Connor said...

That may be an OTH radar, but I'd need to see better imagery to get a better look. It could be a number of things at that resolution.