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Night Vision Autogated tube use in non-dark environments

Derek Zeanah

Private
Full Member
Minuteman
Mar 9, 2012
5
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Georgia
www.thehighroad.org
I understand that gated tubes do a better job of providing full performance in brighter ambient light, but I'm still new to gated tubes and I worry about damaging them. In the past I bought a damaged non-gated tube that had some streaks across the visual field that looked like they were from watching too many headlights pass or something. I was happy to buy that device at a discount, but I don't want to give that discount to someone else...

So, which behaviors are OK, and which can damage a tube? Is it OK to leave the device running in that twilight period between midnight and dawn when things are slowly getting brighter? What about turning them on inside an office with the overhead lights on -- is this OK to do a function check, and is it OK to just leave them on indefinitely in such an environment? There's that video of Camille being wheeled around at SHOT with a prototype PVS-14 mount on her head -- would that have been OK to do with the tubes on? (I just assumed they weren't...)

I'm just trying to understand better so I don't do something stupid I'll regret later.

Thanks.
 
daylight cover, no big deal

I have seen a few older 14s with those burn-in type 'scars' in field field of view, though. probably from headlights and not using the day cover.
Autogated ones don't do it as much I think but it's just not smart to use night vision at day without the cover, imo

plus, you can always turn the gain down if you need to on autogated units
 
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I understand that gated tubes do a better job of providing full performance in brighter ambient light, but I'm still new to gated tubes and I worry about damaging them. In the past I bought a damaged non-gated tube that had some streaks across the visual field that looked like they were from watching too many headlights pass or something. I was happy to buy that device at a discount, but I don't want to give that discount to someone else...

Was the non Gated tube permanently damaged? The streaks might have been able to be "healed" by running the unit with the objective lens sealed off from any light and run for several hours to get rid of the streaking.

So, which behaviors are OK, and which can damage a tube? Is it OK to leave the device running in that twilight period between midnight and dawn when things are slowly getting brighter?
Autogated tubes can handle higher light levels, but you you don't want to expose the tubes to any more light than you would a non gated tube. Anytime you run enough light through the unit to kick in the Bright Source Protection you are shortening the tubes life. Primarily what auto-gating does is keeps the resolution up in high light conditions.


What about turning them on inside an office with the overhead lights on -- is this OK to do a function check, and is it OK to just leave them on indefinitely in such an environment?

No Don't expose the unit to these bright conditions for any more time that you ABSOLUTELY have to. If you don't have a day cover, place your hand FULLY over the objective lens. This will allow you to check screen quality only!

There's that video of Camille being wheeled around at SHOT with a prototype PVS-14 mount on her head -- would that have been OK to do with the tubes on? (I just assumed they weren't...)

I'm just trying to understand better so I don't do something stupid I'll regret later.

Thanks.

In the Video of Camille driving the Rascal around Shot, the two PVS 14s were very much turned on. Those units were running a new prototype day filter we are working on. These are something that will allow for a much better demonstration of a Night Vision Device's capabilities under demo conditions.

So in closing treat, Autogated tubes as you would any other sensitive Night Vision Device. Keep the bright lights OFF of it. These units amplify the existing light levels 50,000 times on average. For every light Photon, tuned into an electron, then pumped through the MCP, 50,000 come out the back end. It will extend the life greatly to not expose Gen 3 Image Intensifiers to undue light levels. WE will have more info forthcoming on the new day filters as well here in the next couple of weeks.
 
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Thanks for the replies folks - it seems like my normal paranoia about not damaging the tubes is just prudence.

Is there any guidance on what level of brightness is acceptable for a recent autogated tube, or is it "minimize exposure to light sources as much as possible?" For instance: sodium streetlights -- something to see in passing because you're keeping them out of the frame, or something that it's OK to keep in view for minutes at a time?
 
Thanks for the replies folks - it seems like my normal paranoia about not damaging the tubes is just prudence.

Is there any guidance on what level of brightness is acceptable for a recent autogated tube, or is it "minimize exposure to light sources as much as possible?" For instance: sodium streetlights -- something to see in passing because you're keeping them out of the frame, or something that it's OK to keep in view for minutes at a time?

Sodium Vapor lights are bright and in passing they won't cause damage (maybe a history streak tube depending) but you should be ok. Now say, set up on a tripod in a surveillance situation? I would try (REALLY HARD) not to have any bright light sources in the view of the Night Vision Device, IF POSSIBLE!
 
Well you can try the "completely shut off the light to the objective and run it overnight" trick to see if that minimizes it. Simply occlude the objective lens so that no light is getting in. this can be accomplished with the day cover with the hole taped over. and then put in a fresh battery and run it (preferably some place safe) overnight and see if the spot has gotten any better by morning. Is the spot completely black or is it a darker area that can be seen through?
 
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