Before we dive into a quick synopsis of tube types it’s important to understand these are minimum qualifying characteristics or metrics. Tubes of all types regularly exceed their minimums. These serve as only a baseline representation point of reference.
PHOTONIS DEFENSE
Photonis Commercial:
A tier just below ECHO. These tubes typically exhibit a dark spot or a data metric that is just outside or below ECHO range. They also exhibit a lower maximum system gain value.
Photonis ECHO:
Minimum 1800 FOM. Typically solid cosmetics with very few dark spots to none. Often in the 2000-2200 FOM range. You may see these referred to as 4G, 4G Hybrid, ECHO 4G. ECHO are technically not 4G tubes but of the 4G family of tubes. They are 4G fallouts.
SNR min: 26.5
Res min: 62
Halo max: 0.95
If SNR is 26.5 then a resolution would need to be 68 to achieve the 1800 min FOM. Is resolution is 62 then SNR would need to be a 29.03.
ELBIT SYSTEMS OF AMERICA
Elbit Systems of America produces 3rd Generation Thin-Filmed intensifiers.
XLSH & SLH are used depending on availability. We hold both to above minimum standards for cosmetics and data metrics. Being a commercial grade tube type these are allowed dark spots in all zones. We do our best to keep our offerings as clean as possible per batch allowance. Minimum specifications are below. Again, we use tubes of higher performance of each to remove the chance of getting a base spec’d tube.
XLSH (Commercial):
SNR min: 21
Res min: 64
Halo max: 1.25
SLH (Commercial):
SNR min: 24
Res min 64
Halo max 1.25
Elbit YH (MIL-SPEC):
This is a MIL-SPEC tube type with ground spot spec allowance from Elbit Systems of America. This means these tubes are held to tighter performance and cosmetic tolerance than commercial grade tubes. In terms of comparison to an L3H tube grade, which more are familiar with, YH would be most similar to an 18um tube in terms of minimums and cosmetic tolerance.
SNR min: 25
Res min: 64
Halo max: 1.0
Elbit VH (Aviator): This is an Aviator tube type from Elbit Systems of America held to Aviator spot specification. The most strict cosmetic tolerance. These tubes routinely exhibit fantastic specification and excellent screen cosmetics.
SNR min: 28
Res min: 64
Halo max: 0.85
L3Harris
L3Harris produces both Thin-Filmed and Unfilmed intensifiers. We only offer their Unfilmed intensifiers for L3H options.
1701 (Commercial):
This is a commercial grade tube type most similar to Elbit XLSH in terms of spec minimums and cosmetic tolerance.
18UM (1800 Series):
This is a MIL-SPEC tube type with a ground spot spec requirement.
SNR min: 24.1 for White 24 for Green (We only offer white)
Res min: 64
Halo max: 1.0
Data Sheets may reflect — in place of SNR minimums as well as Photocathode minimums.
20UM/UA (2000 Series):
These are a grade above 18UM. M are held to ground spot spec requirement A are aviator spot specification.
SNR min: 28
Res min: 64
Halo max: 1.0
Data Sheets may reflect — in place of SNR minimums as well as Photocathode minimums.
22UM/UA (2200 Series):
Grade above 2000 series tubes. Again, M for ground cosmetics A for aviator.
SNR min: 30
Res min: 64
Halo max: 1.0
Data Sheets may reflect — in place of SNR minimums as well as Photocathode minimums.
Wrapping up; these are all MINIMUMS, it’s likely and regular for tubes to exceed their minimums. For instance someone may be worried about getting a lower spec’d XLSH since the minimum FOM is 1344 so technically a 1344 FOM is possible. Not the case, not only do tubes exceed their minimums by a large margin, we also preselect our tubes to be of higher performance. Likewise for other tube types and grades. With Night Vision technology constantly advancing tubes are getting better and better every day. Just a couple of years ago a 28 SNR was incredible and crème de la crème territory. It still is a fantastic value and by no means low. The point is these are only reference points to give you a working understanding for establishing realistic expectations. The more precise and high specification tube you want typically the longer it takes for tubes of that type to become available. Tubes are ordered in batches with only minimums known. They could all be absolute rock star tubes with insane specifications or, more likely, they will be comfortably over their minimums. We will do everything in our power to accommodate and deliver on all requests. Part of that is establishing realistic expectations. If you’re wanting a 40 SNR 81 lp/mm XLSH tube, you have every right to want what you want, but something as such likely won’t come in for a very very long time and is an unrealistic expectation for the given type of tube. This is where the minimums come into play. It would be far more likely for a higher grade tube to come closer to those numbers than one of a lower grade, in this case Commercial.