Zenit NV-100 night vision, any replacement intensifier tubes available?

[CaptDon]

I have one of the Zenit NV-100 moonlight nightscopes. It worked up to my expectations. Sadly the intensifier tube was cracked when the unit was dropped. I got a replacement tube years ago for $100.00 but it was of poor quality. It looked like the phosphor screen was burned from excessive brightness and never had the light gain of the original tube. I was told these tubes were 'graded' like A,B,C as to quality. The factory tube must have been top shelf while the replacement was a used floor sweeping. Anyone got a line on a good quality replacement source? I see the entire NV-100 units going for $65.00 on Ebay. Maybe I should just look for something better? I know this is a 'thermal' forum, but most of the thermal guys I know also dabble in night vision. Thanks!!

[Fraser]

I know the Zenit NV-100 well as I was working in Moscow when they were being sold. Some background to the Zenit units…..

You are quite correct, the IIT’s are graded according to the number and positioning of the phosphor defects, as well as tube performance. I used to talk to the The Moscow dealers about their NV equipment and they showed me the differences between the different price ranges of NV scope. The best ones have excellent, high gain (for Gen1), low defect imagery. The cheapest $20 units were a real ‘lucky dip’. Some were pretty good whilst others had tragic numbers of phosphor defects and low performance.

Now the bad news, the good NV scopes were costing me around $120 in 1997 and the cheapies that I personally tested and selected cost me $20. The Cyclops 1 was the cheapest model and they are actually good if you get a nice tube in one. As I said though…it was a lucky dip on those whereas the expensive units were fitted with hand selected tubes at the time of manufacture. The Zenit NV-100 was basically a Cyclops 1 in different clothes and was dressed up for sale to the West. I could buy the NV-100 in Moscow for $40 while it was selling in the UK for something like £150+. I was warned off of them though as they were known to often have poor performing tubes in them. You obviously got lucky with your unit but I advise against buying another NV-100 unless you can test it first. Spare tubes are not something I have seen for sale, except used ones that can be risky as they break easily in transit if not packed well.

The bottom line is that the Zenit NV-100 is likely better consigned to the NV graveyard and a more modern unit purchased. You could waste a lot of money on that NV-100 and still be unhappy with the image produced due to the variable quality of the tubes. Those tubes are 1960’s technology and OEM’s were using military surplus. As time went on and surplus stock levels dropped, the tube quality also suffered. I did buy a used NV-100 a few years ago purely out of curiosity. I still have it but the performance was pretty awful.

Do your homework and see what models impress their users in the current market. You may be able to save money by purchasing a used unit. Think very carefully before buying units of the same era as the NV-100 though as their high voltage inverters can fail without warning and are difficult to repair.

Fraser

[Fraser]

As a side note to my above story, the best Gen1 NV scope that I bought in Moscow was a personal recommendation of a dealer who I got to know and I trusted. He showed me the White Night model that was very good and cost around $120. That was a very nice unit….but he also showed me a Belarusian unit that actually looked quite plain and ‘utility’ compared to the dressed up White Night and their ilk. I immediately noted that the unit used a 2CR Lithium battery pack, which was unusual at the time. The Belarusian unit contained a Gen1 IIT tube that was described as “Scientific Grade” by the dealer. I tested the unit and was amazed at the performance and clean images that it produced. The dealer said that these were the best unit’s that he could find in the market and they used hand selected high gain, low defect tubes that are a totally different type to those used in the other NV scopes. I suspect that the tubes were Military Surplus Enhanced Gen 1 units that were far rarer than the common 1960’s type Gen1 IIT’s. The Belarusian unit had a smaller lens diameter than the White Night, yet produced a higher gain image. The unit looked like a laser range finder but was equipped with IIT and IR illuminator. I bought both the White Night and the Belarusian NV units. The Belarusian unit cost me $140. I still have both units in the attic

[Fraser]

Pictures of the Cyclops 1, White Night and Belarusian Solar Panther NV scopes.

[CaptDon]

Fraser, thanks for the reply! I think I'll try to offload the NV-100 at a ham radio flea market for maybe $40. It still works well using the I.R. illuminator but the true 'starlight' gain is very poor. I have been thinking about entering into the thermal monocular world but want to limit my cost to maybe $600.00 USD. The ability to see (not necessarily identify) a human in my wooded area at 300 to 400 feet would be my goal. Is there a certain model new or used (if used I would be shopping on Ebay) you would recommend me trying to obtain? It doesn't need to have a color display but some sort of video storage / streaming would be nice. Thanks!!

 

[Fraser]

Hi,

Sadly I am not up to date on thermal monoculars but I do know that they tend to be quite expensive and especially so if the lens is quite powerful for long range working. Used fire fighting thermal cameras are very affordable but they have wide angle (50 Degree) lenses suited to working inside buildings. Longer range surveillance really needs a thermal camera or scope that has a telephoto lens and sadly such lenses are expensive new and used.

You could start another thread asking for advice on thermal spotting scopes as there will likely be owners of such on this forum. I only have the FLIR spotting scopes in my collection. They use the FLIR TAU core and 19mm lens so are quite wide angle. Avoid the FLIR TK as it will not be up to your distance detection needs. The TK uses the Lepton 3 160 x 120 pixel core and that is not the best for long distance applications.

Fraser

[Lambda]

Hello,

Thank you Fraser for your feedback and CaptDon for having started this thread.

Just a short passage for sharing my feeling about this kind of old Russisn/USSR night vision device.
I was starting my teaching in this NV world with an old T3C-2 equipped with a gen 1 tube from the company EKRAN (if i rmember well), wit a lens "Helios" 100mm/2. It was a nice unit quite capable in urban environment with light pollution but far to be usable in passive mode under "starlight" conditions.

I was nevertheless able to improve its performances in passive mode, by making two "modifications:

- the first was to use faster lens (50mm/1.2 for instance, or faster....)
- the second was to modify a bit the voltage DC supply, in order to increase the gain of the tube.

Typically the common concept is to use a low voltage oscillator and to inject the alternatif signal produced by this oscillator in a voltage multiplier (diode bridges in cascades..). The resulting DC high voltage/low current is applied between the photocathode and the "phosphore screen", with the using of a voltage divider for feeding an electrostatic focusing lens assembly.

The tube from the T3C-2 is polarized, between the photocathode and screen, with 19kV voltage. By increasing this value, it is possible to accelerate more the electrons emitted by the photocathode. They will strike with more kinetic energy the "phosphor" screen. It will result in more brightness in the final observed image.

What i did was simply to feed the oscillator from the elctronic on board with, instead of using the 2xAA batteries (2X1.5 serial = 3V), a 9V batterie with a classical good old variable voltage regulator LM317, with a muliturn potentiometer. Therefore, i was able to increase slowly the voltage beyond the 3V required, and by being very progressive for avoiding to generate sparkles, electrical breakdown, i was able to go a bit over 5V, which would correspond to a larger value than the initial 19kV.... The gain was greatly increased, the locust or bee noise also.... .

By using a fast lens and this little trick, i was able to use this tube for doing some astronomy and to start to do terrestrial night vision in more darker conditions...

Sorry for the digression. Hoping it can be useful.

Thank you.

Regards.
Stéphane

[Fraser]

I managed to buy a couple of very nice image intensifiers, one is a Gen2+ rifle sight/spotting scope and the other is an Electrophysics Gen3 Astroscope that mounts on a C mount camera and takes a 42mm Pentax thread lens. Lovely bits of kit but I have no real world use for them 

Fraser

[Bill W]

I managed to buy a couple of very nice image intensifiers, one is a Gen2+ rifle sight/spotting scope and the other is an Electrophysics Gen3 Astroscope that mounts on a C mount camera and takes a 42mm Pentax thread lens. Lovely bits of kit but I have no real world use for them 

Fraser

Point upwards !

Good for galaxies, nebulas and the like.  For some the II must be heavily biased to being red sensitive.  Certainly the case for the one I made with the mechanics you let me have and some EEV tubes.

Bill

[ArsenioDev]

Lovely bits of kit but I have no real world use for them 

Fraser

Fraser, find out how to mount them to an eyepiece (PVS-14 are readily available) or to project into your eyes, then go out and look up.

I've spent HOURS wearing dual tube goggles of Gen3 era, green and white phosphors just staring into the sky, it's somethin special to be able to see that much more than usual, especially during meteor showers or the like.