#189073 - 11/24/09 07:16 AM
Re: EGear Rescue Laser
[Re: raptor]
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Member
Registered: 10/05/09
Posts: 165
Loc: Rens. County, NY
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I would pick red. Green is a bit easier for your eyes to see, but red is way, way easier for night vision systems to see.
Plus, as others have mentioned, red is more of an alert/danger color than green. People associate green with go, good, etc., and red with warning/danger.
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#189077 - 11/24/09 10:07 AM
Re: EGear Rescue Laser
[Re: UpstateTom]
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Addict
Registered: 09/13/07
Posts: 449
Loc: Texas
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A red laser is going to be tougher and harder to break than a green laser.
All consumer green lasers today are "DPSS" types, meaning they contain magical and delicate frequency-doubling optical crystals (blue does too, and yellow lasers even moreso). There's also an IR filter that is absolutely necessary for safety.
Red and violet consumer lasers are diodes, like LED flashlights, and more rugged. There are collimation optics to break, but no frequency-double crystal or an IR filter to knock loose.
Another minor issue is that there is more than one "red" laser. 658nm is the one manufacturers like to use because it's cheaper, but there is also a 635nm diode laser that is a slightly lighter red. The important point is that the human eye is 3x as sensitive to 635nm as 658nm: a 635nm red is easier to see: not as easy as green, but a lot cheaper and more rugged.
Any SAR is going to instantly recognize that a laser beam is not a flashlight, whether it hits them directly or they see the beam sweep across terrain. I doubt the color matters to SAR as long as it can be seen.
Doug has a write-up somewhere on actual experiments on using these to attract searchers. As I recall it takes a little effort to use it right: anyone buying a rescue laser needs to read that article.
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#189083 - 11/24/09 01:59 PM
Re: EGear Rescue Laser
[Re: James_Van_Artsdalen]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2210
Loc: NE Wisconsin
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You might want to read Doug's hands-on test of the Greatland Rescue Lasers: http://www.equipped.org/rescuelaser.htmThe red laser was visible by the naked eye to 20 miles and with night vision goggles to 28 miles. The green laser was visible by the naked eye well beyond 30 miles, and it was visible with night vision goggles.
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#189087 - 11/24/09 02:24 PM
Re: EGear Rescue Laser
[Re: James_Van_Artsdalen]
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Pooh-Bah
Registered: 01/28/01
Posts: 2206
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OK folks, lets all just take a step back and look at the facts. First: You don't have to worry about the fragility of a Green Laser Flare. It is standard issue for U.S. military, especially with various SF contingents in the sandbox. This is not your typical laser pointer Second: The green is MUCH more noticeable than red. No pilot, or anyone else for that matter, is going to ignore a green laser being flashed at them. Third: Red is NOT a universal distress signal color. Most strobes, including those USCG approved, are white, for example. The key is something abnormal that stands out from the surroundings. Fourth: The Green is much easier to aim. Fifth: I carry a Green Laser Flare for personal use. For more info read: http://www.equipped.org/rescuelaser.htm
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#189095 - 11/24/09 03:19 PM
Re: EGear Rescue Laser
[Re: TomApple]
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Geezer
Registered: 06/02/06
Posts: 5357
Loc: SOCAL
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Tom, Did the red laser have the same reflection off the water?
_________________________
Better is the Enemy of Good Enough. Okay, what’s your point??
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#189108 - 11/24/09 05:37 PM
Re: EGear Rescue Laser
[Re: Russ]
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Journeyman
Registered: 09/05/06
Posts: 80
Loc: Suffolk, Va.
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Tom, Did the red laser have the same reflection off the water? We didn't try the red laser. The green laser had such better performance from others testing it, we didn't really waste time with the red one. JFCOM testing showed the green laser to be visible during daytime (except high noon) out to 5 miles. The red laser is largely ineffective during the day. That was another reason not to look closer to the red laser. Tom A.
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#189111 - 11/24/09 06:30 PM
Re: EGear Rescue Laser
[Re: JerryFountain]
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Member
Registered: 06/04/08
Posts: 172
Loc: Colorado
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What do folks think of using a signal laser in urban settings, such as to potentially signal firefighters from your room during a hotel fire?
_________________________
(posting this as someone that has unintentionally done a bunch of stupid stuff in the past and will again...)
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