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8.   ~ight Vision coggles (NVG)~ NA/PVS-7A/7B.  Based on our testing and obser-
vations, the following are some problems that may arise:

     (a)  Blowing Sand.  Both the *7A and 7B are very susceptible to lens damage
from blowing sand.   The only method of proteGting the lenses are to use the
eye piece de-mist shields whenever possible and to always use the lens covers
when the devices are not in use.

     (b)  Humidity and Salt Fog.  The metal parts on the 7B are susceptible to
corrosion under high humidity conditions.   The corrosion experienced during
testing caused movement of the Eye Relief Distance (ERD) mechanism to be dif-
ficult to move.    The ERD mechanism is attached to the head gear and allows the
operator to adjust the ERD duting hands-off use of the NVG.   It was recommend-
ed that the susceptible areas be cadmium plated.   It is not known if they
were.  A small amount of lubricant may prevent the mechanism from sticking.
Care should be taken to keep oil off the lenses since this may damage the op-
tical coating.

     (c)  Use with Protective Masks and Helmets.  The 7A and 7B NVCs are com-
patible with all protective masks and helmets with the following exceptions:

          (1)  When using the NVCs with the Ml7Al chemical/biological protec-
tive mask,   the field-of-view is reduced significantly to approximately    300
This poses a significant hazard, especially with reduced depth perception due
to the monocular objective lens.   The user should practice a scanning tech-
nique (moving the head around a particular scene) that is used by aviators
during NVC flights.

      Cd)   In cold weather, the lenses tend to fog. Fogging is aggravated by
the eye cups which prevent air from circulation.   During testing, operators
exhaled away from the mask.   This helped.  Another useful technique is to re-
move the N~C at regular intervals to allow the fog on the lenses to dissipate.
Wiping the lenses with lens paper, or more practically, a tee shirt, also
helps.   Care should be taken to insure that there is no grease or abrasive
(sand) on the paper or shirt.

9.   OPS Lithium Batteries.  During IOT&E, we had several incidents where lith-
ium batteries overheated in the manpack version of CPS.   In these cases, the
CPS set was being carried in the Army rucksack (Alice Pack) in the AN/PRC-77
radio compartment.   The set fits snugly in the compartment.  When the rucksack
is filled with the soldier1s other necessary items,  there is little air flow
around the set.    During extreme temperatures, we recommend that equipment with
lithium batteries not be operated in enclosed rucksacks.

10.   CPS SI£R.  There have been reports that exposure of SLCR to extreme heat
has lead to shortened battery life and operational problems.   SLCR should be
kept in shaded areas as much as possible to increase battery life and minimize
operational problems.

II.   The following general experiences/observations may be helpful to soldiers
deployed as part of ODS:

     a.  Blowing Sand and Dust.  Generally, problems encountered by electronic

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