PVS-14 How did I do?

I got my new NEPVS-14 from TNVC on Tuesday and wanted to see how the data sheet looks to y'all. I am a newbie to NV but this website has really helped with info and I'm thankful to all for the help. Here are the specs:

Photocathode 2306

EBI .22

Resolution 72

S/N 29.3

Thanks Vic for a fine piece of equipment.

Kick ass tube. I would be proud of that tube.

Thanks. It is a great piece of equipment but I am going to want an IR Illuminator and I'm looking at the Torch vs Luna ELIR-3. Anybody have opinions on the better choice?

Thank you for the kind words about our Night Enforcer unit. I remember that tube quite well.

As for IR illuminators, Besides our Torch which has been around for many years...I can tell you to stand by for another interesting unit hitting the shelves sometime this summer. Testing is continuing...

For ~75-80m max range, a KM2/KM3 head works quite well.

Never used the Luna so I can't comment. I use the Torch and it is a very good long range IR light. I like my Surefire M1 for short ranges (under 75 yards) and indoor use. I also use a GCP laser illuminator but that is overkill for me most of the time. They are also not for public sale. Commercial laser IR illuminators are available but not legal because of FDA regulations. They don't want you hurting yourself or others. That said, many people here own them.

Nice! Pics, or you have gen1!

Damn fine tube.

I am often amazed at just how many 29 + SNR units come out of TNVC.

Nice to see a first post in the night vision forum ! I forgot to say welcome aboard !

Thanks for the welcome. I will get some pics next weekend when I get to the ranch. Thanks again Vic and TNVC for the great NEPVS-14.

OP, did you pay for the hand pick option? After talking with Vic on the phone I decided not to get a hand picked one, and even though I'm totally new to NV, I'm still curious how good my tube will be once it comes in.

Post a scan of the data sheet or you have gen 1 !

In seriousness a data sheet is what hard core NV enthusiasts want to see. Additionally a scan of the data sheet will add some weight to the recent discussions of high spec tubes.

Tiny Crumb

I did get the hand select NEPVS-14 and got a really good one so I am fortunate.

I don't think you can really do that as it is a grey area Itar thing. Stupid Itar thing I know, but can be twisted to be a violation. I am sure it can be scanned and sent to a third party for verification though.

Could someone explain to me in layman's terms what these numbers represent
or point me a direction of thread to better explain please, or why are the below numbers good?


Photocathode 2306

EBI .22

Resolution 72

S/N 29.3

For a truly good tube what would be your minimum spec and what priority if any do you give one vs. another.

I have a Mum Gen2+shp that I could not be happier with frankly and looking to purchase another unit.
Appreciate any help

Photocathode 2306

David, very technical and detailed reply as always, but isn't your decimal point off by one digit on the EBI specs, i.e. 0.1 and 0.25 versus 1.0 and 2.5?

Thank you so much David for the time and detail.

Obviously the finer critiquing of a tube for things such as "Other things include distortion, uniformity and blemishes ( or lack, thereof )." is where experience comes into play as with most things.

Uniformity and blemishes I believe I understand. Distortion I'm picturing as "out of focus" type of effect? So you could still have a tube with great specs and not look as good as another if simply looking at the numbers, if I understand correctly.

Not really, no. 0.1 and 0.22 are correct when referring to microlux.

Distortion in a tube is usually that the image is not linear - so a straight object in reality (such as a power pole ) might appear curved or even have a slight S-shape in it, or objects on the left of the tube might be slightly bigger than the same sized objects on the right side of the tube.

I'm a bit puzzled.

The EBI value listed by the OP should be in the standard form of [(.22 × 10^-11)(lumen)] / cm^2 and not microlux.

[(.22 × 10^-11)(lumen)] / cm^2 ––––> 2.2 × 10^-8 lux ––––> 0.000000022 lux × 1,000,000 = 0.022 microlux

If the EBI on the OP's tube is given in microlux units then the tube is not as great as it appears but on the other hand if it is given in standard for of lux, the tube is very nice.

Yea it's rather obvious that either I'm confused or there is something really bizarre happening.

In the past the (EBI) value for a particular tube was listed in standard form (2.5 x 10^-11lumen/cm^2) and not in the standard decimal form of micro lux.

When I specify that I want a tube with an EBI value of x.xx I can expect that it be in the standard form of lux, not microlux. Though those two values can be transposed it's not how data sheets list them, unless something over at ITT has changed.

So is the OP's data sheet listing EBI as Microlux or some other unit?

Sample Data Sheet since no one else is able to produce one as of yet.



Violation one of ITAR

Y'all have me completely confused on the units of measure.

On the x.x scale, 0.22 would be exceptionally good, particularly in conjunction with the other very favorable values. On the 0.xx scale it would be alot less desirable, but more realistic. The few ITT data sheets that I have seen use the x.x scale, with 2.3 being the maximum acceptable value.

Yes, but those types of figures are also always written in scientific notation - so there is never a leading zero.

I had e-mailed to me a scan of what I'm told is the data sheet referred to in this thread and I can confirm the numbers are exactly as posted in the OP––though I have no clue what any of this means. There is an ITAR warning at the top right of the sheet, but I don't know what that means either. Anyway, the OP's post is in agreement with the sheet.

I'm leaving for the weekend anyway, so please don't ask me anything else about it, as I'm clueless.

Murderman,

The scale is x.x with the maximum acceptable 2.3. The data sheet shows an EBI of .22 which appears to be very good.

Thanks Beekeeper. I didn't want to run afoul of the ITAR regulations.

Both ITT and L-3 use the _ . _ x 10^11 lumens/cm^2 standard/scientific form and since the OP purchased an ITT tubed unit with a factory data sheet (assumed) then it's only reasonable to presume that the EBI is [(0.22 x 10^-11)(lumens/cm^2)].

[(0.22 x 10^-11)(lumens/cm^2)] = 2.2 x 10^-8 lux

and

[(2.2 x 10^-12)(lumens/cm^2)] = 2.2 x 10^-8 lux

The latter is the correct way of writing standard/scientific form but they are both equivalent expressions.

Big difference between .22 x 10^-11 and .22 microlux

.22microlux is not very good

Just for a frame of reference and to put things in a visual context, here are two photo's from two different Mil-Spec tubes that had EBI values below or equal to [(2.5 x 10^-12)(lumens/cm^2)]. The photo's clearly show what EBI values can mean in the real world.

MX-10160A/AVS-6
CONTR. DAAB07-01-D-N414



MX-10160C/AVS-6
CONTR. FA8522-04-D-0015



Levels of illumination where the same for both photo's as where the camera settings. The ambient temperature of 79 degrees fahrenheit is higher than those under which EBI is measured so it's not perfect.







.

Maximum acceptable 2.3, something is just not adding up.

What is the unit of measure the was used to determine the EBI value?

ETA: just found out there is no method listed on these data sheet so there's no way of telling from the data sheet what an EBI of .22 actually means.

These data sheets do say the following though:

"Non-Export Statement - This information is not subject to the controls of the International Traffic in Arms Regulations (ITAR) or the Export Administration Regulations (EAR). However, this information may be restricted from transfer to various embargoed countries under U.S. laws and regulations.

Compasscall,

The ITT data sheet has readings and min and max values set . The max value for the EBI is 2.3. The reading is .22. It does not show the units on the EBI. TNVC provided me with a great NEPVS-14. I don't give a rats a** if you believe it or not.

0.22 EBI on the "2.3" scale is absolutely superb, particularly in conjunction with the other high end specs. I have gotten some really nice tubes from TNVC, but not like that one....hang on to it!

He was once known as Anakin Skywalker...


Being serious and keeping on topic. I have a couple ITT data cards and I don't know what math figures they use. But the ITT cards seem to use the x.xx method. Below 1.0 would be a great tube. I believe milspec figures are below 2.5 which I think is a bit high but everybody has a opinion. Based on the figures and data cards I have seen ITT use, 0.22 would be a smoking EBI and well below milspec figures.

Don't ask me the math involved to achieve these numbers. When you two start tossing long math equations about I head out to my boat for fishing and a beer. I am sure I won't be alone. These are both tubes I once owned. My pics were stolen so they are both freely seen on the web.



The EBI on this ITT tube is 1.060 which is very good and well below milspec.



As you can see with the second sheet the EBI is not as good but still pretty good in my opinion. The others figures are very good as you can see. We have a EBI of 1.58

Great numbers on your PVS-14 NE ! Sorry to continue the geekiness, but would you mind sharing the Halo number from the data sheet?

Texag82, if your tube has an EBI of 0.22 on the scale of x.x then it's not great at all, It's a freak. I have never heard of such a low EBI ever and I think it will be a long long time before anyone on this forum manages to find a tube to beat it.

David,

Thanks to you for the compliment and thanks to Victor at TNVC for selling me this unit.

Knowing he is a connoisseur of high spec tubes, I think compasscall was just trying to figure out if that was the indeed the true number due to the differing units of measurement. As cj7hawk said that is a REALLY low number to have.

This is exactly what I was after and not whether texag82 was making stuff.

@texag82 WOW you have a lot of misdirected hostility toward me. Where have I attacked you or said you where making stuff up, If anything I question what method ITT is deriving these values from because the maximum of 2.3 is a lot lower than even Mil requirements (by a fair margin) if they are using the same method? You may not give a rats a** how to read specs or ever care but some of us do and for those of us who do tube specs are a pretty important piece in understanding the technology. You posted your specs asking for it to be evaluated which is exactly what was done. Reading and understanding the Non-Export Statement on your data sheet might have helped expedite this evaluation.

Compasscall

The ITT data sheet that came with the PVS-14 states "This information is subject to the controls of the International Traffic in Arms Regulations (ITAR). This is why I didn't put up a copy of the data sheet. The rats a** wasn't how to understand the specs but whether you believe me or not.

Then you are justified in not putting it up. The ITT Data Record have been sent says it is not subject to the controls of ITAR, so you can see the discrepancy.



I believed you where stating the EBI value just as it was listed on the sheet, the confusing was in the way it which ITT determined this value. I see your point but never did I question your honesty.

Op- anyway you can take a picture of the tube would love to see how well it performs!!!

Great example photos compasscall, but now I'm wondering about electronic manual gain tubes like the MX-11769. Does turning the gain down on a PVS-14 have any effect on the EBI level seen in the tube? Or is this simply a constant illumination level irregardless of the amount of gain the tube is set at?

If you turn your gain down a bit, you'll notice much less scintillations, and it appears that the contrast of the scene is better, but is it really?

Yes, it is better. The gain control primarily affects the MCP which at higher gain levels produces much higher levels of noise. The MCP is the biggest contributor of noise in the entire system. So when the gain is turned down, you get much better contrast. ( Contrast ~ S/N )

Disregarding any electro-static forces, the levels of illumination needed to overcome the veiling affects of dark current (thermally generated electrons), the levels at which these thermal electron are generated would remain relatively constant regardless of any change in the PC to MCP potential.

Since the photo cathode is the primary source (not sole source) of all thermally generated electrons, reducing the PC to MCP potential would act on thermal electrons in the same way as photo electrons, reduced multiplication. For the most part the photo cathode act separately from the MCP, regardless of the MCP voltage the photo cathode will generate the same ratio of photons to electrons. The photo-cathode, just as with photoelectrons, will generate the same quantity of thermal electrons regardless of the MCP voltage. So reducing the MCP voltage just reduces the gain or multiplication of the thermal electrons being generated at the photo-cathode. Keep in mind that I have taken electro static forces out of this because I don’t believe they have a significant enough effect on dark current, at least that the human eye can discern.

So reducing the MCP voltage does not reduce thermally generated electrons at the photo-cathode.

In all but the darkest environments, photoelectrons will out number thermal electrons, so reducing MCP voltage results in a proportional decrease in both photo and thermal electrons. Since there are less thermal electrons than photoelectrons to begin, decreasing MCP voltage will have a greater visual affect on thermal electrons, increasing contrast.

Poor contrast as it relates to dark current: Thermal Electrons (dark current) = Photo Electrons and when Photo electrons aren’t being generated in significant quantity to overcome the veiling effect of the thermal electrons

Good contrast: Thermal Electrons (dark current < Photo Electrons and when photo-electrons are generated in great enough numbers to overcome the veiling affect of thermal electrons.




David keeps bringing up a very important point, thermal electrons increase with temperature (drastically), with the increase in thermal electrons, higher levels of illumination (photo-electrons) are going to be required to maintain an image with good contrast.

I’ve had the experience of using a tube at sea level, where the temperature was 79 degrees F and then 45 minutes later at 9000ft where the temperature was in the upper 30’s. At sea level the dark current was very noticeable but hardly apparent at 9000ft where the temperature was low.

For those interested in the affects on dark current and cathode temperature check out the following videos:

Long version: http://www.youtube.com/watch?v=U7qZd2dG8uI

Short version:http://www.youtube.com/watch?v=iS4yu4LQJ54

Hey guys, thanks for the detailed answer, the videos and photos are a great help CompassCall, thanks for that.

Oh Hell yes! This sounds right up My ally. I love My Torch but, just want a bit "more".. Would this new toy be of interest to Me?

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