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12/11/2018 1:58:31 AM
Posted: 12/3/2018 8:20:44 AM EST
I was wondering if temperature has any effect on nvg tube's ? Recently I was at the cabin with my pvs-14 gsci version, and it would seem that the colder it got, the better it worked..or could this just be my imagination ?

https://www.youtube.com/watch?v=tjNTtvK6_tk
Link Posted: 12/3/2018 8:44:07 AM EST
Originally Posted By stianfred:
I was wondering if temperature has any effect on nvg tube's ? Recently I was at the cabin with my pvs-14 gsci version, and it would seem that the colder it got, the better it worked..or could this just be my imagination ?

https://www.youtube.com/watch?v=tjNTtvK6_tk
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I dont know that mine works better. I always felt like my tube needed to "warm up"

ever since I got my 14 from TNVC in cold weather especially when I turn it on and set the gain a few seconds after it being on it flickers a little.
after 3-4 minutes once its been running the adjustment is smooth.

For me this is more pronounced in cold weather and takes a few minutes longer.

but overall performance seems to be the same regardless of summer/winter
Link Posted: 12/3/2018 9:12:14 AM EST
[Last Edit: 12/3/2018 9:20:21 AM EST by cm]
as the tube gets colder, the ebi current drops, so there is less apparent noise interfering with viewing

affects of temp on ebi


how the level of light illuminating something has to be above the ebi, for things to be visualized


thanks to past member for creating videos
Link Posted: 12/3/2018 9:33:50 PM EST
Originally Posted By stianfred:
I was wondering if temperature has any effect on nvg tube's ?
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cold weather takes moisture out of the air and settles dust which makes make nvgs better. At least in AK it did during the winter.
Link Posted: 12/4/2018 5:20:39 AM EST
Really interesting video's, thanks for sharing ! So in theory..if you put the pvs-14 in the fridge, and use it afterward, one would have a clearer image ?
Link Posted: 12/4/2018 8:35:42 AM EST
Yes, but putting NODs in the fridge and then bringing them out into normal temperature and humid air results in fogging lenses.

Though, if you purge them and wrap them in cling wrap, you might prevent that.
Link Posted: 12/6/2018 4:42:15 PM EST
[Last Edit: 12/6/2018 4:44:34 PM EST by Alex_B]
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Originally Posted By cj7hawk:
Yes, but putting NODs in the fridge and then bringing them out into normal temperature and humid air results in fogging lenses.

Though, if you purge them and wrap them in cling wrap, you might prevent that.
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I wonder if anyone has ever tried to cool a tube with a peltier module in a NVD.

Edit: Ahhh Yes. http://www.freepatentsonline.com/3751709.pdf
Link Posted: 12/6/2018 11:02:10 PM EST
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Originally Posted By Alex_B:

I wonder if anyone has ever tried to cool a tube with a peltier module in a NVD.

Edit: Ahhh Yes. http://www.freepatentsonline.com/3751709.pdf
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That's a slick arrangement.

Photomultipliers (great grandfather of image intensifiers) are pretty routinely cooled in a variety of scientific applications. Depending on the photocathode, dark current (EBI) can decrease by a factor of two for every ~3C. Benefits can compound pretty quick. Want to say I've seen temps as low as -80C for cooled photomultipliers.
Link Posted: 12/7/2018 7:21:55 AM EST
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Originally Posted By txdx:

That's a slick arrangement.

Photomultipliers (great grandfather of image intensifiers) are pretty routinely cooled in a variety of scientific applications. Depending on the photocathode, dark current (EBI) can decrease by a factor of two for every ~3C. Benefits can compound pretty quick. Want to say I've seen temps as low as -80C for cooled photomultipliers.
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Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
Link Posted: 12/7/2018 8:24:19 AM EST
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Originally Posted By cj7hawk:
Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
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Originally Posted By cj7hawk:
Originally Posted By txdx:

That's a slick arrangement.

Photomultipliers (great grandfather of image intensifiers) are pretty routinely cooled in a variety of scientific applications. Depending on the photocathode, dark current (EBI) can decrease by a factor of two for every ~3C. Benefits can compound pretty quick. Want to say I've seen temps as low as -80C for cooled photomultipliers.
Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
Yep it is true of all electronics. In fact some old satellite amplifiers use in communications receivers used nitrogen to cool them to reduce the noise. Even newer amps for that purpose are rated by temperature rather than noise figure.
Link Posted: 12/7/2018 10:41:03 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By cj7hawk:

Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
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Did the 1928 concept or 1934 prototype image tube rely on secondary emission for gain? I'm all for historical tidbits. Don't think image tubes had gain as a product of electron multiplication through secondary emission until an MCP was stuck in? If so, PMTs predate that. Image dissectors (like an orthicon) that had gain through secondary emission aren't the type of "image tubes" I had in mind either. ;)
Link Posted: 12/7/2018 11:31:45 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By cj7hawk:
Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
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View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By cj7hawk:
Originally Posted By txdx:

That's a slick arrangement.

Photomultipliers (great grandfather of image intensifiers) are pretty routinely cooled in a variety of scientific applications. Depending on the photocathode, dark current (EBI) can decrease by a factor of two for every ~3C. Benefits can compound pretty quick. Want to say I've seen temps as low as -80C for cooled photomultipliers.
Image Intensifier tubes: Concept, 1928, First working 1934, Netherlands.
Photomultipliers: Concept 1930, First working, 1934, Russia.

I don't think this quite qualifies as "great grandfather"... :)

David.
I would agree, a photomultiplier tube used secondary emission to detect very low levels of light but were incapable of anything to do with images by themselves. they were used in some very elementary TV equipment to produce pictures but just as a light detector.
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