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Posted: 8/6/2001 8:28:39 AM EDT
how do you tell if it is still good? what i mean is, when buying say...used AN-PVS7B's how do you know they arent gonna die soon? anyway of telling? i remember when i was in the Army we had to send our goggles in to be "purged" periodically (when those little black spots got too numerous) what is that and can it be done in the civilian world? Also, are these the best NVG's on the market? anyone other than ITT make them? anyone to watch out for? (ie bad product) thanks
Link Posted: 8/6/2001 8:43:32 AM EDT
[Last Edit: 8/6/2001 8:41:33 AM EDT by havoc]
Unfortunately, there is no way to tell how much life is left on an image intensifier. Unless it is EXTREMELY used (upwards of 9000 hours on a GenIII unit, for example) then you will start to see fading, darkening, and distortion around the edges of the viewed image. If you want to be absolutely sure, buy new from the factory or a licensed distributor. Those little black spots aren't always able to be removed... Some are produced during the manufacturing process. Certain parts in the image tube are chemically "grown" in a vacuum chamber. The process you referred to is called nitrogen purging, and blankets the interior of the unit body with dry gas. This can pressurize particles out of the unit also. It is a service that will cost usually $50 to $100 at certain civilian night vision dealers / repair shops. Both Litton and ITT sell and service the PVS-7B and -7D, however only Litton makes the -7A and -7C. These two companies are also the only producers of image intensifiers used in US Military night vision equipment. The best? I personally like them alot. However it depends on your application and of course, wallet thickness. I however really enjoy the AN/PVS-14 I have now. The only vendors I would watch out for: Almost every single night vision dealer at a gun show is selling shit, to include surplus tubes in new housings, with falsified tube sheets (the data sheets that outline specs and performance of the intensifier in the specific unit). I have a list of people I deal with often. Email me, and I will be glad to help you. (edited for spelling)
Link Posted: 8/6/2001 7:15:08 PM EDT
ok, couple more questions how can you tell the difference between 7a's and 7b's?? other than the serial number plate (which if i remember correctly is rivited on...seems too easy to change) the 7a's are gen 2+ right? b's are gen 3? any way to know by looking through them? anyway to know through physical inpection (ie touching and looking, smelling tasting etc...) if it is a shitty tube inside a new/good housing? hmmm...this doesnt taste like a good tube ;) thanks for the info man, i appreciate it...
Link Posted: 8/6/2001 8:01:39 PM EDT
SkaerE: All of the PVS-7 series goggles are available in GenII or GenIII. The differences are in the housings, whereas the -7A and the -7C are essentially the same, and the -7B and -7D are essentially the same also. Some of the differences: the PVS-7C, built by Litton, uses a facemask that allows the goggles to flip-up, and is submersible to 66 feet. The -7A does not "flip-up", and is only rated at 3 feet for about 30 minutes. The -7D differs from the -7B in that it uses an improved circuit board for better flash response, and uses the top of the line GenIII 64 lp/mm MINIMUM resolution image intensifier, with an enhanced signal to noise ratio, etc. You'll know if its a shitty tube the second you look through it at night, and see: - A lot of "crackling" or scintillation, which may mean the tube is running hot, or has had the gain turned up to appear brighter -Blemishes, including dark areas and larger than normal black spots directly in the field of view (the center of the viewed image, vs. the edges) -Fading or darkening of any edges, or a "shadow" that creeps across one side of the viewed scene -Tube burn, caused by using the unit / tube in conditions that were too bright, looking at a bright light source / laser / reticle for an extended time (also called reticle burn in scope intensifiers) -And any other thing that just looks abnormal If there is any trace of superglue, JB weld, pro-poxy, duct or electrical tape, etc, you probably don't want it. Any screws missing, won't lock into the head harness, "takes a minute to light up", lenses won't focus, etc, the same thing goes... Here are some pics to help: AN/PVS-7A and -7C (from Litton): [img]www.littoneos.com/products/images/ANPVS-7C_square.jpg[/img] AN/PVS-7B and -7D (from Litton, ITT, NVEC): [img]www.littoneos.com/products/images/ANPVS-7D.jpg[/img] Hope this helps, havoc
Link Posted: 8/7/2001 5:43:49 AM EDT
CIB: Always go with American made, and if you can, a USGI / Military type unit. This is for a few reasons: Mainly because these will have the highest number of parts and accessories available, and are easier to service. Also, the optics in the system will be designed to make the most of the image intensifier, giving you the best performance for the unit's intended purpose. As far as an actual "product endorsement": The good ' ol AN/PVS-4 is a daisy. It is a little heavy compared to the smaller AMT brand scopes, but it is well made, and usually very available. Surplus PVS-4's can be had for as little as $1100, depending on tube quality and exterior / lens condition. And weapon mounts exist for just about everything, including the M60 and AT-4, should you be so lucky! Here's a pic: [img]www.littoneos.com/products/images/ANPVS-4.jpg[/img] Happy (GenII) hunting, havoc
Link Posted: 8/7/2001 5:57:11 AM EDT
HAVOC, Got a question, I've been considering a night vision device for checking out the deer herd. The smart ones hit the woods when they see the spotlight. Anyway, I will need to see from 50yds to 200yds, 50yds being very optimistic. What generation would you suggest and what brand? Also I'm on a budget is there anything capable of doing what I'm asking for at a reasonable cost?
Link Posted: 8/7/2001 6:03:46 AM EDT
GWIGG: It sounds like you could do what you want with a GenI unit, however distances approaching 200 yards, and any farther, will require the use of a high-powered infrared spotlight. Or, just go with GenII. The problem is, when you see GenII compared to GenI, you don't want GenI anymore. The same is true for GenIII vs. GenII. For your stated purpose however, I think GenII will do good things for you. As far as a brand: only USA made, with US made image intensifiers (i.e. Litton or ITT image tubes). What are your cost constraints?
Link Posted: 8/7/2001 6:09:59 AM EDT
With some creative accounting I think I could go between $300 and $500.
Link Posted: 8/7/2001 6:17:21 AM EDT
Originally Posted By GWIGG: With some creative accounting I think I could go between $300 and $500.
View Quote
OK. For that you are somewhat limited to GenI. The AN/PVS-2 is a Vietnam-Era US made night vision scope that can be found for this price range. There were lots of beautiful factory reconditioned units available not long ago, try: Morovision [url]www.morovision.com[/url] North American Integrated Technologies [url]www.nait.com[/url] And of course, there's the EE and Ebay. Some may disagree here, and say GenI Russian is OK. IMO you're better off with a flashlight. It is very hard to find a good Russian unit. If you need other sources, let me know. havoc
Link Posted: 8/7/2001 6:23:47 AM EDT
I was afraid you were going to say that. Thanks for the info, I think I'll probably stick to scaring them off with my spotlight [:D]
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