Re: Pads near Cockeyed Ridge South East of Groom

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Message posted by Skeet (Member since 06/29/2022) on July 05, 2022 at 15:41:27 PST:

The radar should reach over the north east hill, at least for short-range work.

Using the viewshed and elevation profile tools in Google Earth, we can find the highest points and elevations from the pads.
Line of sight to Groom Lake:
Highest point in the N/E hill:

Using some trig, we can work out the angle needed to clear the hill. Assuming whatever is being tested sits 10ft above the pad, the angle needed would be around 3.5. The distance from the centre of groom lake to the west pad is 54,800ft/10 miles which would give us a gain of 3,351ft. The pad sits 1,121ft above the groom lakebed so all in all the radar floor would be 4,472ft above ground level at the base or 8,872ft MSL. At 300 miles the floor gain would be over 100,000 ft - far too high if radar distance was being tested. (You're right, Joerg)

The Chinese YLC-8E is fairly new so the pads weren't built to test that. The Russian "Nebo-M" radar system is another interesting one:

These radar systems tend to have a command & control vehicle plus 2-3 radars. A long-range detection radar (HF/VHF/UHF or L-band) and a medium/short-range radar (S/C/X or Ku-band) used for fire-control/missile guidance.

Another possible candidate is the older "Nebo-SVU" which was introduced in 2001. The same year the pads we're built.

In-depth article on this system:

Of particular interest from the article is this graphic:
It shows the estimated detection range in relation to RCS size. The detection range drops off exponentially as the RCS sized is reduced.

Compare that chart with this table of estimated aircraft RCS sizes:

B-52: 100
B-1(A/B): 10
F-15: 25
F-16: 5
F-35 / JSF: 0.005
F-117: 0.003
insect: 0.001
F-22: 0.0001
B-2: 0.0001

50nm and closer would likely be a key testing range. Anything further than 50nm and I doubt the aircraft would even register, let alone 300 miles.

Clearly the USAF would be very interested to see how close they needed to get to a Nebo-SVU type radar before being detected. I think we're getting close.

In Reply to: Re: Pads near Cockeyed Ridge South East of Groom posted by Joerg (Webmaster) on July 05, 2022 at 10:17:11 PST:


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