Chinese over-the-horizon backscatter RADAR

OTH-B sites (Tx and Rx) in Hubei province

Site locations:

Transmitter site: 32°20'11.28" N 112°42'29.56" E
Receiver site: 31°37'09.15" N 111°55'07.52" E

Source: China's OTH Network, Sean O'Connor.  http://geimint.blogspot.tw/2010/05/chinas-oth-network.html

Overview of Transmitter site: 32°20'11.28" N 112°42'29.56" E.

It is clear that there are 3 groups of transmitter antenna array at this site, therefore theoretically, at least 3 radar signals and on 3 different radio frequencies can be transmitted from this site simultaneously.

Each group of antenna array can also be divided and used by multiple transmitters, so that more radar siganls can be sent out from this site simultaneously.

Group of transmitter antenna array #1, consisting of 8 high-gain large log periodic antennas (LPA) for low to high frequency operations.

The 4 equipment rooms on the left might be accommodating 4 (or more) high power HF transmitters and phase combining network in order to provide the maximum transmitter output power. An array of 8 LPAs also provide higher antenna gain and plus high transmitter output power for the maximum effective radiating power (ERP).

The transmitters in the 4 equipment rooms and the 8 LPAs can also be divided and used individually, or in different paired combinations for multiple carrier/frequency operations. Actual signal analysis shows that the transmitters and LPAs are paired for 2 carriers/frequencies operations.

The LPAs of this group are installed so closed to each other, wonder if there's any RF coupling issues.

Transmitter antenna array #2, consisting of 30 LPA but for higher frequency operation.

Transmitter antenna array #3, consisting of 30 LPA(?) but for even higher frequency operation.

Receiver site: 31°37'09.15" N 111°55'07.52" E

60-degree sector (assumed) beaming to 120 degrees south east, 700 ... 3500 km coverage. Needs another 400 km to reach Guam and Saipan.

How about coverag for rest of Japan? Well, there is another one building in the Inner Mongolia of China. right now.

New OTH-B site found in Inner Mongolia autonomous region

Receiver site location: 41°25'05.88" N 111°04'21.99" E, anyone knows where the transmitter site is located?

A combined 700 ... 3500 km coverage of both Hubei and Inner Mongolia sites will be like the photo below, The Inner Mongoloia (Rx) site has a 60-degree sector (assumed) beaming to 100 degrees south east.