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IT IS ASSUMED THAT YOU ARE ALREADY FAMILIAR WITH THE OPERATION OF THE MT24 SYSTEM.
1. Power Connections
All boxes are powered off 12V batteries, and cables are configured so that they
can be connected to terminals on 12V lead acid batteries. Do not modify these
cables in any way. Standard connections are red and to positive and black to
negative. Each cable as a green LED that is lit when the proper polarity exists
on the power cable.
DO NOT CONNECT A BOX TO THE POWER CABLE IF THE GREEN LIGHT IS NOT LIT!!!
Failure to follow this instruction will result in (expensive) damage to components which
you get to pay to repair.
Based on very limited experience, a 120 A-h battery will power the CSU or computer
for 24 hour runs without any problems. The FAMs will run off much smaller batteries, if
weight is a consideration. All equipment was configured to run off external 12V lead
acid batteries to facilitate overseas work. Airlines will not ship batteries on passenger
flights (FAA regulations), and many remote areas are reached only by passenger flights.
2. Electrodes
The electrodes (see diagram)provided by EMSOC are Pb-PbCl2
electrodes designed and built by Steve Park at UCR. They have standard connectors for
the FAM modules. Some electrodes have long leads, while others have short ones.
Use the long lead electrodes at the FAM boxes as the negative sides of your dipoles
(each dipole requires a positive electrode and a negative one. For the purposes of
noise reduction, the negative electrodes at the FAM box are separate.)
The electrodes are designed to be shipped and stored dry. See the EMSOC web page
for electrode design. A user will need to ship NaCl (not grocery store quality!) and
PbCl2 powder along with the electrodes. These can be purchased from a chemical supply
house. Prior to the field survey, prepare a saturated solution of distilled water, PbCl2
(at least 33 g/l), and NaCl (at least 333 g/l).
Mix well and let it stand to warm up (the mixing process is endothermic and the lower
temperature reduces the salt solubility in the solution). Then, add a teaspoon of
PbCl2 and 2-3 teaspoon of NaCl to each electrode (the extra salt guarantees saturation
of the solution). Add solution to fill to within 3 cm of top. Seal the electrode and
tape the top to prevent the stopper from coming loose. The electrodes are now ready
to use. They can be transported in a bucket of wet bentonite mud (made with NaCl
solution) or in a NaCl brine. This brine can be made with table salt as it does not
go inside the electrode. Only the solution inside the electrode must be pure.
The electrodes are installed by digging a hole 30-35 cm deep and adding about 2 kg of
bentonite mud made with NaCl solution to the bottom of the hole. Wet the hole thoroughly
with NaCl solution (4-6 l) and then set the porous top of the electrode in the bentonite
mud. Fill the hole carefully and bury the electrode completely. Connect to the cable/FAM
and you are off!
Once the survey is done, the electrodes are drained and washed out thoroughly with
distilled water. They can be dried and shipped empty. Be sure to dispose of the
solution in accordance with local laws regarding toxic wastes; it contains lead.
3. Electric Lines
EMSOC has provided 10 e-lines with length of 100 m. These are rolled on spools
designed to be laid from the FAM to the electrode. The connector on the outside
of the spool is the male plug into the FAM. Do not roll these up backwards!
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