Assembly and Usage Instructions for the Ground Penetrating Radar
Unit
1) Setup
What to
Bring to Field:
-
These GPR Instructions
-
GPR Control Unit and power cell
-
Transmitter and Receiver Antenna Electronic Modules
with power cells for each
-
4 black plastic Control Unit screws
-
Control Unit backpack frame and computer rack
-
2 Antenna Elements (Transmitter and Receiver) which
adequate to the frequency at which you wish to scan
-
Optical Cables:
-
1 single strand cable with black connectors
-
1 double strand cable of cables with both red and black
connectors
-
One 25 pin parallel port cable
NOTE: the fiber optic cables are
extremely fragile. Do not bend,
pull, twist, step on, or chew on them.
-
Antenna Handles:
-
2 “Y” shaped wooden supports, each have two metal snap
connectors and four holes.
-
2 wooden separators which are placed horizontally
between the supports
NOTE: the lengths of the separator bars vary
depending on the type of antenna being used.
The chart below gives the recommended lengths for each antenna.
|
Separator Length
|
.6 m
|
1.0 m
|
2.0 m
|
|
Frequency on Antenna
|
200 Mhz
|
100 Mhz
|
50 Mhz
|
-
8 screws and wingnuts are
required to assemble the antenna handle
2) Assembly
-
Attach the 2 horizontal separators to the 2 vertical
supports with the 8 screws and wingnuts.
NOTE:
some of the horizontal separators have make shift
handles for attaching the hip chain. Put
this separator on the top.
-
Locate the two Antenna Electronics and a power cell for
each. Attach the power cells to the
Antenna Electronic using the clamps on each side of the power cells.
-
Locate the Antenna Elements (large black bow tie shaped
things) you wish to use and attach an Antenna Electronic unit to each. (The ports are setup in such a way that the
transmitter and receiver ports will only fit with their corresponding ports.)
-
Place the Antennas on the ground and attach the handle
to the hooks on either side of the wire jacks.
Be sure the fit is tight. You may
have to turn the hooks to adjust their height.
-
Locate the Control Unit and it’s
power cell. Attach the power cell.
-
Locate the back-pack frame and 4 black plastic screws.
-
Place the Control Unit on the back of the pack with the
jacks and LEDs facing outward. Line up the holes on the pack with the holes
on the sides of the Control Unit and secure it with the screws.
NOTE: The tips of the cables are very delicate and
can be broken off easily. They do go in
the jacks easily, it’s just a matter of lining up the metal indention on the
jack with the metal bit on the cable then pushing the cable down so that the
groves on the sides line up, turning clockwise and releasing it so that the
cable is locked in place.
-
Locate the Optical cables and remove the protective
covers from both the cables and the jacks on the Control Unit. Connect one end of the black single strand
cable to the “T” jack on the Control Unit then connect the other end to the “T”
jack on the Antenna Electronic.
-
Connect the red and black double strand cable to the
corresponding “R” and “D” jacks on the Control Unit and Antenna
Electronic. Be sure to save all the
plugs from the cables from the cables and Control Unit in a bag, they get lost
easily.
-
Locate the hip chain distance meter and attach the 9
pin serial port to the Control Unit at the port marked “Enc”.
-
Attach the hip chain unit to either a makeshift holder
on the wooden antenna handle or secure it to your person.
-
Locate the laptop PC and 25 pin parallel cable.
-
With the computer turned off, attach the parallel
connector to the parallel port on the PC then to the port marked “LPT 1” on the
Control Unit.
-
Put on the Control Unit pack and adjust the straps for
comfort. Locate the metal foldout
computer stand and hook it into the metal rings on both shoulder straps and let
it hang.
-
Place the computer on the stand and line up the velcro strips to secure it.
-
Turn on the Control Unit and both Antennas.
-
Boot up the PC and allow the antenna to warm up for a
few minutes.
NOTE: If an LED on any unit does not light up the
power cell is empty. If an LED does not
blink it is not connected properly. If
an LED is blinking that it is connected and transmitting data.
3) Using the GPR
-
With everything online and connected find the MALA Geoscience Ground Vision program and run it.
-
For a simple reflection scan Goto
File à New à New SCH (single
channel measurement)
-
Input the file name, the directory to save the data to,
type and frequncy of Antenna, unit of measure for the
trigger, and the type of trigger. Don’t
hit “Start Measurement” till you are ready to begain.
-
You can click on “Settings” to change the measurement
settings. There is a great deal of
modification that can be done at this point but for a simple scan use the
defaults. Be sure to hit “Search for
Time Zero” to insure that the pulses from the radar system are being processed
most efficiently.
-
Locate your transect and stake
the string from the hip chain trigger into the ground at the starting
point. As you move the GPR will take
readings at the interval entered into the startup menu as the string is let
out.
-
Do not drag the bare Antenna on the ground. It might be helpful to secure a tarp around
the unit and drag it if the ground is level.
-
Hitting F6 will stop the measurements and F5 will start
them again.
-
Walk your transect
slowly. Keep the “Work Load” meter out
of the red and watch the data appear on the screen.
-
Filters can be applied to the data by going to Radargram à Filter à and moving the filters into the Applied
slot with the Apply button. The details of each filter and in the manual.
-
After measurements are done there is no need to save
the data as it is done automatically.
End of Directions for a Simple Reflection Scan
