Talk:Radome

Irregular Geodesic domes

The radomes in the image here, are clearly based on a geodesic dome but have a more irregular distribution of the nodes. Can anyone confirm that the nodes are displaced randomly to avoid some sort of interference with the radar signal. -- Solipsist 08:17, 27 Mar 2005 (UTC)

A Guess?

It looks to me that the distortion in the pattern of the structure is because it is not a perfect sphere. The bottom is open to allow for the hardware inside. If the materials of construction are transparent to electromagnetic waves, then it shouldn't matter.

64.47.102.66 15:58, 22 February 2007 (UTC)Andrew Young-

• Every dome is open (incomplete) at the bottom! —Tamfang (talk) 09:06, 1 October 2015 (UTC)

Good point. Every "geodesic" dome is no longer a geodesic. It's quite easy (but mostly useless) to build a geodesic sphere. Once it's cut into a dome though, especially for a hemisphere, the forces on the lower members are no longer purely tension and compression- i.e. some bending forces are introduced. Small domes ignore this, badly built hippy-domes in Oregon fail by the bottom members breaking under an unexpected bending load, larges domes are sometimes carefully designed with an uneven and strengthened base to keep the forces in the sticks above simple. Andy Dingley (talk) 10:58, 1 October 2015 (UTC)

Purpose

This sentence looks very clumsy to me: "Its shape is easily identified by its hardshell, which has strong properties against being damaged." Would anything be lost by the simpler: "It is easily identified by its strong shell."

or even:

"It is easily identified by its strong, damage-resistant, hardshell." - if 'hardshell' is a necessary piece of jargon. Dawright12 (talk) 11:00, 18 April 2011 (UTC)

Tinfoil Hat

I doubt anyone can confirm it, but are radomes sometimes used to disguise where the equipment within is being targeted? Captainmax 00:56, 15 August 2005 (UTC)

Before reading your question, I'd just added a note to this effect to the article! In the example of Menwith Hill, some dishes were uncovered at one point and observers could deduce which commercial satellites were being monitered. A PhD thesis on Menwith Hill also notes this useful propery of radomes. — Matt Crypto 21:52, 12 November 2005 (UTC)

Question

This may be stupid to ask but are the radar devices still able to perform their job while under the radomes? I think this should be in the article.

MAYBE an Answer

The Irraregular Gedesic Domes are to facilitate manufacturing of a two demensional shape and assembling it into a 3D shape with structural integrity. Example = a sphere is very strong, but to build a sphere of any size would be cost prohibitive and difficult at any large size, so you take small 2D shapes and sew them together and get a 3D soccer ball. As for the radomes use while covered, in some cases it is nessacary to remove the radome but if the antenna is designed correctly, taking into account the radome, they can remain covered and not interfere with RF transmission —The preceding unsigned comment was added by 204.203.50.2 (talk) 18:47, 16 February 2007 (UTC).

answer pt 2

radomes are made of material invisible to radar. It just blasts right through, the same way visible light passes through a clear pane of glass almost unimpeded. As an example, consider this: a car radio recieves radio transmissions much like a radar does, and a car radio will still pick up a clear signal in a typical garage attached to a suburban home even with all the doors and windows of the garage shut. The signal goes right through. —The preceding unsigned comment was added by 69.61.184.12 (talk) 14:55, 22 February 2007 (UTC).

I think transparency is such a common and familiar concept that it needs no elaboration here. Dawright12 (talk) 12:11, 18 April 2011 (UTC)

Answer pt 3

The material used is transparent to microwaves, and one of the driving forces behind the UK development of fibreglass/GRP was for producing radomes for the RAF's night fighter force, moulded plywood having been used previously.

Windloading

I have updated the article to note that radomes reduce wind loading. Not sure how to reference facts showing reduced windloading, here's one. See the datasheets here: http://www.pacwireless.com/products/soliddish_5ghz.shtml From a physics explanation, imaging a parachute right side up, and upside down. The upside down parachute is the shape of a radome and will go through the wind easier. The right side up chute is like a dish without a radome (or Mary Poppins umbrella) and will catch the wind much more effectively. --Jp498 (talk) 01:14, 1 March 2008 (UTC)

Answer pt 4

Reference: RADC-TN-61-189 October 1961 EFFECTS OF CW-396A RIGID RADOME ON AN/FPS-6 PERFORMANCE Oct 1961 Charles M. Blank Project 5579 Task 45384 Rome Air Development Center Air Force Systems Commend United States Air Force Griffiss Air Force Base, New York see http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0266133

Yes, radomes can degrade radar set performance.

The CW-396A is a geodesic, rigid radome comprised of triangular shaped panels (primarily of uniform size and shape) connected together by plastic flanges (ribs) with a thin fiberglass cover fastened to the outside edge of the flanges (ribs). Equatorial diameter is 55 ft (50-ft at base). Height: 43 ft from base mounting ring to top. Designed to withstand 130 mph winds with no ice load. With 8 inches of glazed ice or 16 inches of rime ice the wind limits are 87 mph. Approximate weight 17,000 pounds. Provided as part of the AN/GPA-89 radar set group. Widely used for AN/FPS-6/8/20 series radar sets

The AN/FPS-6 is an Air Force height finder radar set and they were used at most US Cold War radar stations for providing the altitude of enemy aircraft.

An AN/FPS-6 installed inside a CW-396A is pictured in the online radar museum (radomes.org/museum) on the FPS-6 radar equipment page. Note the parallel lines formed by the ribs of the uniformly shaped radome panels.

The general conclusion reached in this study was the electromagnetic scattering effects of small metal objects in the radome are negligible. This is consistent with the size and arrangement of the connecting metal or dielectric bolts used to connect the panels of a reinforced, plastic, geodesic panels into a radome. However, there is significant RF scattering due to the radome panel flanges (ribs). Investigation revealed that this was due to the large dielectric cap strips which were placed over the radome panel flanges (ribs) for structural reinforcement. This was the source of side lobe interference (clutter) on the AN/FPS/6 RHI display console (OA-929)out to about 50nm. It was also noted that when there is significant ground clutter on the RHI display console, the effects of CW-396A panel scattering is exacerbated. Ground clutter is attributed to the location of a radar set and RF propagation of side lobes by the antenna.

The study recommended that the CW-396A radome not be used with the AN/FPS-6. Where possible, the rigid radome design should provide an irregular (not parallel) pattern of radome panels to help reduce the effects of RF scattering with S band radar sets. Sgwxly (talk) 23:40, 17 August 2015 (UTC)