PVS-31A, 2376+ FOM
L3Harris | Minimum Specifications and Spots
Tubes with a model code UM (Unlimited FOM Military) and UA (Unlimited FOM Aviation) have differing tolerances for dark spots.- UM tubes limit spots that are >.003" to Zone 2 and 3. Spots that are >.003" are not permitted in Zone 1.
- UA tubes limit spots that are >.003" to Zone 3. Spots >.003" are not permitted in Zone 1 or 2.
Military Spec
Performance summary:
L3 Unfilmed White Phosphor | 18UM:
- SNR: 24.1 minimum
- FOM: 1540 minimum
- Center Resolution: 64 lp/mm minimum
L3 Unfilmed White Phosphor | 1610 tubes (2376+ FOM models of PVS-31A, 1531):
- SNR: 33 minimum
- FOM: 2376 minimum
- Center Resolution: 72 lp/mm minimum
Spot summary:
No spots >.003" are allowable in Zone 1. Max spot size of .009". While spot sizes and quantities per zone are listed below, there's a max of 4 spots allowed per tube which are limited to Zone 2 and Zone 3.
| Spot Size | Zone 1 | Zone 2 | Zone 3 |
| (Inches) | Limit | Limit | Limit |
| >.012 | 0 | 0 | 0 |
| >.009 | 0 | 0 | 0 |
| >.006-.009 | 0 | 1 | 1 |
| >.003-.006 | 0 | 2 | 2 |
| Bright Spots | 0 | 0 | 0 |
| Dark spots </= .003” are acceptable |
Aviation Spec
Performance summary:
L3 Unfilmed White Phosphor | 20UA:
- SNR: 28 minimum
- FOM: 1792 minimum
- Center Resolution: 64 lp/mm minimum
L3 Unfilmed White Phosphor | High FOM, 36 SNR min:
- SNR: 36 minimum
- FOM: 2304 minimum
- Center Resolution: 64 lp/mm minimum
- Exceeds 24UA
| Spot Size | Zone 1 | Zone 2 | Zone 3 |
| (Inches) | Limit | Limit | Limit |
| >.012 | 0 | 0 | 0 |
| >.009 | 0 | 0 | 0 |
| >.006-.009 | 0 | 0 | 1 |
| >.003-.006 | 0 | 0 | 2 |
| Bright Spots | 0 | 0 | 0 |
| Dark spots </= .003” are acceptable |
A final note-
As manufacturing capability has improved and technology has continued to advance, many tubes now well exceed their model minimums for FOM, SNR, and Center Resolution. While spots are a normal by-product of the intensifier tube manufacturing process, they are becoming smaller and less frequent.
Model minimums only define the minimum performance threshold that a tube must meet (UM and UA tubes have no defined maximum). As a result, it is possible for a 18UM tube to exceed the performance of a 20UA tube (or 24UA) both for FOM and cosmetics.
What is ITAR?
International Traffic in Arms Regulations (ITAR) is a United States regulation that controls the manufacture, sale, and distribution of defense related articles and services, and data. The ITAR covers a variety of items on the United States Munitions List beyond night vision (e.g. ballistic / missile targeting systems, etc) and serves to protect military related technologies and protect U.S. national security.
Violating ITAR is a serious crime that caries penalties that include fines & imprisonment. Night vision devices utilize protected technology that provide a unique overmatch advantage in night time operations. We ask that our customers help us safeguard this technology.
Our products are only available for sale to US citizens and permanent legal residents located in the U.S. We will only ship within the U.S.
Can I travel outside of the country with my night vision device?
Generally speaking, no. Transferring a device out of the country (whether shipping it or traveling with it) is considering an export of defense technology on the US Munitions List and is illegal under the ITAR without a license.
For further information, contact the Directorate of Defense Trade Controls @ (202) 663-1282 and / or the U.S. Department of Commerce.
