Document Page: First | Prev | Next | All | Image | This Release | Search

 equipment will include clogged filters0 mechanical problems with switches and
 connectors, and poor electrical contact caused by sand and dust interference.
 Dust.accumulation will also reduce the efficiency of heat sinks.   Filters and
 external heat sinks must be cleaned often to avoid overheating problems.
 Switches and connectors must be protected as well as is practical and cleaned
 to prevent build-up.  Connectors should be i~pected before mating and sand
 removed to prevent damage to electrical contacts and mechanical fasteners.
 Covering equipment with anything available (cloth, plastic, etc) will help
 during dust storms. - - Use caution when cleaning equipment, filters, etc. with
 compressed air.  We have found that high pressure air can damage filters and
 drive sand and dust particles past equipment seals, making things worse.

     b.  High Ambient Temperature.  Overheating is an obvious problem with
 electronic equipment.  Not only can it cause immediate failure0  it can
 accelerate component aging and dramatically reduce NTBF.   There are many things
 that can be done to reduce the risk of damage due to high temperatures.   Turn
-equipment off when not needed.   Seek shade for electronic equipment - even the
 shadow from a building or other~equipment will help.   Ensure un-restricted air
 flow around equipment.  Clean filters and external heat sinks often.   Operate
 equipment at night when mission permits.

     C.  Large Day/Night~Temperature Differentials.   Condensation when
 temperatures drop rapidly at night can cause problems for electronic equipment.
 The risk can be minimized by keeping the equipment powered-on at night.

     d.  Solar Leading of Power Cables.   Power cables lose efficiency as
 temperatures rise.   Consider providing shade or burying cables to protect them
 from solar heating.

     e.  Salt Marsh.   Salt can cause corrosion of electrical contacts resulting
 in reduced performance and early failure.   Inspect connectors/contacts often
 for signs of corrosion and clean using methods appropriate for the equipment
 and conditions.

 12.   The following are some problems that may be experienced and possible so-
 lutions:

     a.  Poor Electrical Cround:   This can be a difficult problem to overcome in
 dry sand/rocky terrain.  Experience in conducting tests in the Yuma and Cila
 Bend areas of Arizona show that a chemical pit may be helpful.   Bury copper
 with a large surface area (copper plate0 coils of copper cable, etc) or use
 multiple ground rods.  Bond the rods together to form a single ground point.
 Treat the pit with available chemicals (rock salt0 epsom salt, etc).   Keep the
 pit moist.  Use waste water from a latrine, condensate from air conditioners,
 etc.  Field expediency:  Install ground rods in a latrine pit.   A grourJ
 plane/counterpoise can provide an effective ground for antennas.   Construct
 the ground plane with bare copper wire0  if available0 or field wire wD-l (ex
 pedient).  Make it large enough for the operating frequency (consult appropri-
 ate technical manual or see AF Manual 52-19, Antenna System) and connect it in
 grid fashion.  Use as much wire as is available.   Two wires are better than
 one; one is better than none.   When a counterpoise is used for transmitting
 antennas, personnel must be kept clear since it may present a serious electri-
 cal shock hazard.

Document Page: First | Prev | Next | All | Image | This Release | Search