Wind turbine causes problems with military radar?

[Seekscore]

I am outside Colorado Springs and have been waiting 2 months to get an FAA clearance to install my tower. I applied for a 65' tower with the county and they told me I fell under an FAA Part 77 obstruction area. They basically investigate whether I am going to be an obstacle to air traffic. Apparently, I am good to go with everything except the Air Force is still investigating or at least that is what the hold up is now. The FAA guy told me they were investigating the interference my 12' turbine is going to cause to their radars. I found this article later today that explained it a little more. I am 12 miles as the crow flies from Peterson AFB. Hopefully, they will give me the ok soon so I can get my permit from the county.

http://www.csindy.com/colorado/dang-that-wind/Content?oid=1679562

Mike

I am actually the one in the article listed east of Falcon.

[Ronnn]

If that's all it takes to interfere with their radar we are in even bigger trouble than I thought. I wonder what was wrong with their radar on that one day..... must have been those pesky crystal radio fiends.

Just took a look at the link. Norad, perfect, they were busy playing games that one day. It just happend to be about terrorists stealing aircraft for their own purposes and all of their boys were playing elsewhere. Immagine that! Those big windfarm turbines, if I'm not mistaken, run on a adifferent principle than our axial flux macnines and a at lot higher power.

Ron

[David HK]

Tongue in cheek you could ask the powers that be to move the AFB, or, alternatively, write to President Obama along the the lines that if he is cutting the size of the armed forces then this AFB should be at the top of the list.

Hope you see the sense of humour. 

David in HK

[fabricator]

What a steaming pile of BS, a 65 foot tower is gonna interfere with a billion dollar radar system, at least you are dealing with the Air Farce and not the Federal Bureau of Incompetence.

[Sr WiNdTeCh]

Damn... I work on 65 and 80 METER towers..... on 100+ Turbine Wind Farms.... I know a few farms have been held up in constructing because of local farmer's having their own landing strips but never a radar problem...

[Bruce S]

I read the link. It actually looks like they are only looking to delay stuff long enough for them to catch up. The post states they can't block a project, but everyone else looks to them.
Okay by me...
I can understand them wanting the make sure the radar will not have a blind spot or ground scatter noise. It's not the power producing part it's the moving blades they want to make sure about.
Makes sense to me.

He may have over stated, but nowadays its CYA Since he's an out going commander; he's not wanting this to come back on him.

I do like the upbeat part that AWEA talks about CO continuing to bring online so many more 'Mills..and how many home the help power.

Bummer about the 3 month delay..

Cheers
Bruce S

[Ungrounded Lightning Rod]

Apparently, I am good to go with everything except the Air Force is still investigating or at least that is what the hold up is now. The FAA guy told me they were investigating the interference my 12' turbine is going to cause to their radars.

I used to work in a radar research lab.

Search radars eliminate "ground clutter" by suppressing signals that haven't been shifted in frequency due to the target's motion.  Other types of radar use similar hacks.  They've gotten a LOT smarter.  But they're still designed around stationary and nearly-stationary stuff on the ground and moving stuff in the air.  An air force base will have all SORTS of radars, some of which may be "too smart for their own good" (and many of which may still be secret).

The problem with wind farms is that they have lots of raised metal moving in (and thus reflecting with a doppler shift) the radar beam.  The tips are moving at windspeed times 6 or so while the rest of the blades are moving at progressively slower speeds as you get closer to the hub.  This looks like a whole fleet of vehicles moving at a range of speeds, mostly suitable speeds for aircraft.

Then there are double-reflections from the angles BETWEEN the blades, which can do a roadsign-like reflection back into the antenna, making a tiny "corner reflector" look like something enormous (though this is mainly a problem for 90 degree angles).  And specular reflections (glints) when the blades line up at right angles to the line to the antenna.

Multiply by a forest of turbines spread out to catch a lot of wind.

I shudder...

Point out to the engineer (assuming this is correct) that:
 - You've got only one mill.
 - It's a little bugger, not a giant commercial wind machine.
 - You're using wooden blades (which reflect very little signal) and are willing to skip using (or remove if it causes problems) any metallic tape  that protects the leading edge and to do balancing with weights at the hub rather than out on the blades.  (Metal near the hub is moving slowly and shouldn't be an issue.)
 - You're using three blades and a single flat vane on the tail so "corner reflection" shouldn't be an issue.

The tower and tail are not an issue and small, homebrew, non-metallic blades should not be, either.

[Seekscore]

I actually work with radar and have for the last 22 years. I've operated and maintained several different types of ground based systems. I understand what you are saying and know first hand what kind of interference it will cause. Hardly any or least very minimal. If they are truly concerned about it then it must be a newer technology than I am not familiar with. I doubt they would get much more return off this turbine than they would with a tall radio antenna. I am sure they are not distinguishing between the commercial wind farms and small residential turbines which are vastly different in the amount of interference. They have their experts so I know they wouldn't listen to anything I tell them anyway. It is what it is and I support the military 100%.

My screen name of "Seekscore" is actually the name of the first radar system I worked on back in 88. The AN/TPQ-43 Seek Score.
http://www.globalsecurity.org/military/systems/aircraft/systems/an-tpq-43.htm

It was just interesting to learn that they consider wind turbines as a possible National Security Threat. When they said it was being held up by the Air Force, I just assumed it was because it could have been an obstacle for air traffic until I talked to the FAA to see what was taking so long.

Mike

[JYL]

I just wonder if this has really to do with Radar -- in the sens of detection of incoming airplane.
I can understand that some of the newer drone fly low, are pretty small and have a low radar signature,,, so that USAF might want to monitor the airspace almost at the level of the ground.  However, newer radars are pretty good to learn normal disturbance.  So, I am not sure that is the real issue.

Maybe, one day, we will learn that the problem might be related to "Interception missile" or others defensive weapon.  Those might not have the necessary computing power and might get fooled by a windmill when trying to intercept a low flying airplane/drone.

[bob golding]

Maybe, one day, we will learn that the problem might be related to "Interception missile" or others defensive weapon.  Those might not have the necessary computing power and might get fooled by a windmill when trying to intercept a low flying airplane/drone.

 gosh  that would concentrate the mind.