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Old 14 December 2009, 14:05   #91
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... I could take say a 2L coke bottle and cover it in strips of scotchlite tape and stick it on the boat and I'd show up no problem at all.
I was previously unaware of the possibility that metallic tape could enhance radar returns, but I do now wonder if it might make a real difference in a search and rescue situation?

A lifeboat looking for casualties is going to have the radar ramped up well beyond anything shipping would use, so although the difference in return may be minute it may also be of benefit.
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Old 14 December 2009, 14:09   #92
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I was previously unaware of the possibility that metallic tape could enhance radar returns, but I do now wonder if it might make a real difference in a search and rescue situation?

A lifeboat looking for casualties is going to have the radar ramped up well beyond anything shipping would use, so although the difference in return may be minute it may also be of benefit.
If its got any metal in then it would make some difference.
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Old 14 December 2009, 14:19   #93
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I was previously unaware of the possibility that metallic tape could enhance radar returns, but I do now wonder if it might make a real difference in a search and rescue situation?

A lifeboat looking for casualties is going to have the radar ramped up well beyond anything shipping would use, so although the difference in return may be minute it may also be of benefit.
I'm certainly no radar expert - but my understanding is that a flat object (say a square of metal (or foil) like the patches of reflective tape (assuming they are of a type that reflect radar at all) on some l/j's) will reflect the radar in the same way as a mirror reflects light. To show up on the radar screen it needs to be reflected back at the sending station. Just like a mirror with light this can only happen when the surface is exactly perpendicular to the radar in both the horizontal and vertical planes.

If it is on a spherical surface there is always a part of the surface which is perpendicular to the radar - but actually compared to the sphere itself this is only a tiny fraction. On a irregular shaped object the returns will be inconsistent and the automated clutter removal is likely to filter it - although I don't know what "FishNet" mode is - perhaps there is a filter specifically for finding small objects?

Quote:
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If its got any metal in then it would make some difference.
I think that's too simplistic, in addition to the above "shape" factors the metallic component will need to be bigger that the wavelength of the radar otherwise it should be invisible to the radar.
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Old 14 December 2009, 14:22   #94
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although I don't know what "FishNet" mode is - perhaps there is a filter specifically for finding small objects?
Thats for Stu's "ladies" in Peterhead.
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Old 14 December 2009, 14:57   #95
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I'm certainly no radar expert - but my understanding is that a flat object (say a square of metal (or foil) like the patches of reflective tape (assuming they are of a type that reflect radar at all) on some l/j's) will reflect the radar in the same way as a mirror reflects light. To show up on the radar screen it needs to be reflected back at the sending station. Just like a mirror with light this can only happen when the surface is exactly perpendicular to the radar in both the horizontal and vertical planes.

If it is on a spherical surface there is always a part of the surface which is perpendicular to the radar - but actually compared to the sphere itself this is only a tiny fraction. On a irregular shaped object the returns will be inconsistent and the automated clutter removal is likely to filter it - although I don't know what "FishNet" mode is - perhaps there is a filter specifically for finding small objects?

I think that's too simplistic, in addition to the above "shape" factors the metallic component will need to be bigger that the wavelength of the radar otherwise it should be invisible to the radar.
3M™ Scotchlite™ Reflective Material - SOLAS Grade 3150-A

I have just looked in the store and the actual tape I use is as above. I use the 50mm width and have found it to be superb.
You just need to have a very clean and dry surface when you stick it on.
My current Radar is the JRC Alphatron and this has the Fishnet setting.
If any of you are passing by one day I will be more than happy to take you out to demonstrate the difference.
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Old 14 December 2009, 15:15   #96
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Lets just chuck a selection of RIBnet members over the side & see who shows up the strongest on radar depending on what they have stuck to them ? ( assuming they float and have put on an auto inflating jacket........)

All in the name of science and safety ?

PS if not wearing a killcord we wont come back for you ................
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Old 14 December 2009, 15:31   #97
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Lets just chuck a selection of RIBnet members over the side & see who shows up the strongest on radar depending on what they have stuck to them ? ( assuming they float and have put on an auto inflating jacket........)

All in the name of science and safety ?
Can I pick them?
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Old 14 December 2009, 15:42   #98
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Can I pick them?
I like the plan chaps. I have not done a MOB drill yet this month.
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Old 14 December 2009, 16:07   #99
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I like the plan chaps. I have not done a MOB drill yet this month.
Can we choose who recover too.
I told JK we needed a polling option on here!
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Old 14 December 2009, 16:23   #100
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3M™ Scotchlite™ Reflective Material - SOLAS Grade 3150-A

You just need to have a very clean and dry surface when you stick it on.
My current Radar is the JRC Alphatron and this has the Fishnet setting.
If any of you are passing by one day I will be more than happy to take you out to demonstrate the difference.
I'm up for it, I'll be tugging (on the pull) again Jan/feb and it'll me in Europe. Willemshaven is a great port and we like to run their for weather cover if we can.

Chewy, they are not my ladies I was merely indiccating to Gt5 (ive upgraded him, cos hes fond of the throttle) the options available if he needed a squeeze that didn't feel the cold.
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