Quoted:



So, I was perusing some night vision places that I don't post at. I just like to see what other information is out and about. I run across a guy who I have had many previous "discussions" with. We don't care for each other but that is beside the point. The point is the information he is putting out.





.7mw IR lasers "destroying hundreds of tubes". To keep it fair they were discussing use on a pistol at close ranges. For this topic let us assume typical pistol ranges of 25 to 50 feet. I am not a laser expert but do know a fair amount about tubes. I also have used and own quite a few lasers, even the milspec high power ones (no agent Wu I don't own any milspec lasers) . I have NEVER seen one tube even slightly damaged by a .7mw IR laser.





I am sure it could be done if someone was a complete idiot and reflected their IR laser directly back into the tube for prolonged duration. Yes it could be done but you would need close range, a highly reflective surface and prolonged exposure. Anyone that has ever shot a pistol knows how hard it would be to keep it laser steady by hand for a prolonged period of time. Maybe if the pistol was locked in a vise this is possible.





The poster goes on to say how this is detrimental to tube life and damages them. Well, every time we turn our NV on it is detrimental to tube life as a night vision tube has a finite life span. To say .7mw IR laser use damages and affects tube life is like saying rain is hard on shingles. Yes, use of your night vision in higher light environments affects tube life. Still, I have never seen a Gen 3 tube completely worn out. Never even seen a mislpec tube worn out and they use them more than any casual user.





Rain will wear out shingles in the life expectancy of the shingle. But they were designed to handle rain. A night vision tube is no different. The designers know the tubes will be used in all types of varying lighting conditions. They are designed to handle that and not significantly effect tube life. Certainly shooting a pistol mounted .7mw IR laser with a 14 mounted on your head is nothing to be concerned about. Not only would you need the pistol held dead steady and straight on axis your head would have to be as well and both for prolonged periods at .7mw.





This just does not happen in real world use. I still wait to see these hundreds of tubes destroyed from pistol IR laser use. Talked to a few prominent NV friends and company's, they have not seen one either. Just a post to dispel some myths from a guy peddling "special tubes"...
ETA: If anyone here has a damaged tube from a .7mw IR laser I would love to hear about it and see some pics through the tube.

Quoted:[]LOLOL, I remember that thread! It's sad thread really. The part that's so funny, is that he called it technical advice.
 

Quoted:
I have a gen 3 tube damaged by IR lasers, however this was purposefully done in a destructive test. From the sound of it they where testing with full power military IR lasers to see the damaged caused to a gen 3 tube for a study with the DOD. The tube has several bad spots/grey areas but is still very serviceable. This was all disclosed when I bought the tube and I got it dirt cheap. Is this guy selling the damaged tubes?

Quoted:
You should see all the dumb ass "oops" moments I have had with my "heavy" use tube, and it performs just as good as the day i got it

-Brothers friend looking directly at head lights
-in garage and wife turned on the lights
-Direct shot .7 ir laser (testing pressure switch was holding it backwards so it shot right in the tube)
-eotech turned on to high long enough to burn image into tube (put it in box, left it on overnight and it fixed it)
-had pvs14 turned on with IR, went to turn it off, only went 1 click so i only turned IR off not the mono, then took in fully lit room long enough to where the bright light cut off turned it off (I have done this at least 2 times)
-using da torch at way too close a distance, so bright i could see the honeycome

They can definitely take some abuse.

Quoted:
I read that thread on the hide. I cruise through there on occasion and get amused with the ramblings.  One thing is for certain with that guy who posted
Poster has never been shot at
Poster has never shot at anyone
Poster has never been in any confrontation except with a hog in a field it seems by the ramblings
Poster has never been to any formal night vision training classes but says he's done this or that with his night vision hog hunting

I will have to admit I've taken a tactical night vision class a few years back and also with some other night vision trainers. I've also worked with several high power lasers for over 10 years and have yet to burn shit down in any of our issued gear. It's too bad some people want to burn down the good guys, and I think clasky is one of the good guys who really knows his shit and that goes the rest of their crew I have talked with on occasion.

Quoted:

  This thread is one of the funniest I've read in a long time...

Well, I find it absolutely unbelievable that someone can get away with such ridiculous claims, but there are plenty of dumb people in the world and they are the most easily separated from their money. Military lasers have a lot more power and specular damage is rare enough. I guess when you're selling snake oil, it's important to find gullible customers.

The first question that should come to mind, of course, is to ask "How bright can something be before it damages a tube?"

For that, we have the metric "Bright Source Protection"...  It's one of the "Milspec" metrics that defines tube performance. It's not something they measure on every tube, but most tubes should meet this spec. It's been around for over 30 years and hasn't really changed at all...


[div style='margin-left: 40px;'][div style='margin-left: 40px;']Bright source protection.  With operating potential applied, the assembly shall not be damaged (see 3.6.9) when subjected to an input illumination of not less than 50 milli-lumens concentrated on the photocathode within an area no greater than one square millimeter for a time interval not less than one minute.  There shall be no discernible damage (see 3.6.9) after a non-operating period of not more than 24 hours.




50 Millilumens. Well, how much is that? According to http://hyperphysics.phy-astr.gsu.edu/hbase/vision/lumpow.html, it's about 5mW for Infrared and higher.  How many millilumens are we talking about here? About 0.7mW... Not a big amount at all, and this is the TOTAL amount of light we're talking - so that's a direct hit... Or *perfect* specular reflection at close range. And they are claiming laser reflection from pigs is causing damage?

Now, I have to admit that I don't know about American pics, other than that they taste different to Aussie pigs, but Aussie pigs don't look like mirrors. In fact, they have a kind of matt finish to them here. Are there any Chrome pigs in the US??? And even if the pig is made of Chrome, we're still taking about a minute of exposure... Might it make a mark on your NOD? Sure. But there should be NO DISCERNABLE DAMAGE... Unless, of course, you got some kind of power supply that doesn't conform to the milspec, like I don't know, nuclear-blast-proof-PSUs or something... Or maybe when their recoil-proof tube fails the black spot isn't "recoil damage" it's "laser damage", I dunno.  


OK, I did kind of gloss over some stuff there, but a pistol laser? Come on, it's not even fixed in the image. Maybe I should add "Standing like a statue, looking at reflection of the laser on a flat section of chrome pig for a period of one minute and one second with a slightly more powerful laser than 5mW..." would exceed that standard. Barely.

Now, bright lights like lasers aren't good for image intensifiers, but I'm not going to start freaking out just because someone flashes an "eyesafe" laser at my NOD. Speaking of which, the above is the "Turned on and Non-gating" safety margin, but what does eyesafe mean anyway?

Well, firstly, eyesafe means that even if the laser was fixed on the retina for an extended period of time, it couldn't delivery enough power to cause damage, because there's not enough heating to cause damage. Image tubes are kind of the same, when not turned on. ( and when turned on, it's about BSP )


Also, it's not 0.7mW at higher IR wavelengths ( eg, around 900nm ) - it's about 1mW that's considered eyesafe... This is because IR wavelengths carry less energy per photon that visible wavelengths. You can even calculate it yourself if you're into lasers - eg, http://prod.sandia.gov/techlib/access-control.cgi/2002/021315.pdf

Now do I really have to do that technical stuff? Not really. Because most military lasers are around 3mW to 5mW ( All less than the magical "5mW" limit ), for up-close work, so I could just work off of that as a guideline, while perhaps considering how many people over the past 30 years have said "Oh crap, I shouldn't have lased that pig, it just destroyed my NOD".... Oh yeah, number of people = zero. Seriously. they don't even get LIFS ( Laser Protection filters ) for NODs to filter the rifle-mounted lasers at all... That's about how concerned the military is about this... But hey, do a google search on "My laser destroyed my night vision"...

Still, sometimes 1mW is a bit too bright for up-close work, even if it's not damaging... And 0.7mW is the same... So how to dull them?
With a Neutral Density Filter... Cost about $20 on ebay...
http://en.wikipedia.org/wiki/Neutral_density_filter
A NG9 filter will get rid of around 85~90% of the laser's intensity at IR spectral frequencies - http://www.stockoptics.com/media/datasheets/neutraldensity/NG9.pdf - And they come in 12mm dia, by either 1mm or 3mm thick... Perfect for small lasers... And optical grade glass too ( something I am planning on using in an upcoming project ).


Regards
David

 

Quoted:


Actually there are some heavily armored pigs out there, here's proof:



http://www.1023clearfm.com/files/pig.jpg

Quoted:
LOL

Every good pig deserves a custom coat of arms!

Quoted:



Been out for a bit, thought I would chime in after my in box and emails blowing up.  





Been using high power IR lasers for many years and REALLY training with them for many years.  We also surround ourselves with real NV trainers with strong SOF backgrounds and we all have never ever ruined a tube from our H.P. lasers.  In fact, one of our Directors as most know Kyle has 18 years as a SF Army puke and also headed up the NV training section of ITT at around 4 years+. (Yea he was the one that got that memo, about a person making phone calls and writings about ITT autogated power supplies alerting enemy guard dogs. I saw the emails circle my desk too from way back when).  He also has never ruined a tube from any of his years using HP lasers, and he has yet to even use a Class 1 system.  He mitigates blooming with IR illumination and NO meaningful degradation of resolution occurs, nor is it an "old school" bad way practice. In fact 99% of all REAL NV trainers use these techniques. In fact, that is the beauty of a modern AG supply, when the NOD dims down, most of the resolution maintains. Now if we're talking non-AG, with standard ABC, indeed you will see resolution degradation.  Heck I used to show pics of this many, years ago.  Need to dig those up some time.





Now .7mW just came about 1.5 years ago with the FDA approving Class 1's at 1mW or below for commercial sales.  Laser manufactures like to use .7mW to insure they don't approach that legal threshold. Laser Devices was the first company to break through the legal mumbo jumbo and set the market on fire a few years ago.  We talked with them for YEARS to get one to market, and their legal persistence finally paid off.  Since that time, a slew of other manufactures jumped on the band wagon. Some good and not so good Class 1's are also in abundance.  We tested them all that are on our web site,  but of course do not carry every brand for our own personal testing reasons.  





There are handgun IR  laser systems out there and the ones we work with, all work in the .1mW -,2mW arena for close in handgun work.  In fact many are about to see more of these short range entries very soon. Hang tight, as MUCH more is about to come down the pipe line that will allow even more versatility.  





Hope this clears up the myths running amok.





Vic Di Cosola

Quoted:

Well now that we bring up nothing is "perfect"...What does one do when the "others" will surely invent the issue that .1mW IR laser power levels are too low, you cannot see your aiming point due to IR illumination, moonlight etc.  The sky will be sure to fall then....

Vic

Quoted:

  Nah, the guys who come up with the crazy ideas to sell their snake oil never touch the same subject twice... People have already had time to learn the truth and will likely spot their strategy a second time, so they come up with something new...

If I had to guess, it will probably be about camouflage paint on NV causing psychological injury ( gotta have black! ) or perhaps X-rays from over-stressed tubes ( Need that new eyepiece filter... )  Maybe something really imaginative such as needing to use counter-clockwise threads so that the shock caused by the rifling in the barrel is countered...

Or hardened against sunspot activity ( Did you know that Sunspots cause image field degradation due to ionic wind and disturbances to the electrostatic field inside the image tube? It results in a 37.3 % degradation of performance caused by harmonic vibration of the un-oxidised cesium atoms in the photocathode. But it can be shielded magnetically with the "Brock Energy Polariser" technology originalled developed by a racing car driver. It makes up for deficiencies in the earth's van-allen belt distribution by the stuff that comes from a bull's arse... Methane I think it is, but it might be something else )


Give them another year to think something up and I'm sure they will. :)

David


 

Quoted:




It was my iPhone 4s.



I had to jerry rig a Daniel Defense rail box with a slit in it to hold my phone, but it works well enough for me.



http://i61.photobucket.com/albums/h80/BrOdBaNd_2006/DC8EF558-E897-470B-BB4D-E05AAF51C930-827-000000573C1E95A5_zps7a51e185.jpg



http://i61.photobucket.com/albums/h80/BrOdBaNd_2006/photo6_zpsc8e62160.jpg

Quoted:
  LoL! My bad, I should have used more words - I meant your lineup of different lasers was "perfect", not that 0.1 mW was ideal :) - but you're right about chasing a moving target there - what is ideal for one purpose is insufficient for another. I was thinking that the option for an ultra-low-power laser is very useful for people needing to place shots very accurately at close range, eg, rimfire used for pest control of rats.

I suppose some future lasers will have very adjustable outputs that can be field set or at least modified by the user - I know some of the LDI models have that feature - depending on the pressure pad you install, it changes the function of the laser and different pads are colorcoded for application. (eg, one lead is "eyesafe" while another is full power. )

Regards
David