For backpack use - similar to the cart, but different:
1. Connect the battery packs to the transmitter and receiver electronics. The
transmitter electronics has a single fiber optic cable connecter on top with
a T next to it. The receiver electronics has dual fiber optic cable connectors
on top with an R next to one connector and a D next to the other. Be sure that
battery packs are latched to each piece of electronics.
2. Connect the battery pack to the control unit (located inside of backpack)
3. Attach transmitter and receiver electronics to the transmitter and receiver antenna, respectively. Matching up the appropriate male/female serial pairs does this. Also, be certain to latch the electronics to the antennae.
4. Assemble the wooden antenna handles and attach them to the transmitter and receiver electronics. Do not pull hard on latch. If you have to pull hard, then rotate latch hooks counterclockwise to extend them upwards. This provides more slack to the latches. Use the 0.6 meter wooden separator bars for the 200 MHz antenna, the 1.0 meter wooden separator bars for the 100 MHz antenna, and the 2.0 meter separator bars for the 50 MHz antenna.
5. Connect one end of the single jumper fiber optic cable to the transmitter electronics and the other end to the control unit. The control unit has the letter T near the appropriate fiber optic cable connector. You must line up the notch on the fiber optic cable connector with the groove in the connector for the electronics. Once the notch is lined up, push down, and rotate to lock cable. Feed one end of the cable through the velcro window in the backpack so that the backpack may be zipped up with the cables connected to the control unit. NOTE: It is beneficial to have a small resealable plastic bag so that all the protective caps for the cables and cable connectors can be stored and not be lost.
6. Connect one end of the dual jumper fiber optic cable to the receiver electronics and the other end to the control unit. The control unit has the letters R and D next to the appropriate fiber optic cable connectors. NOTE: Make certain that if you have the black side of the fiber optic cable connected to R on the electronics that the black side is also connected to R on the control unit. Feed one end of the cable through the velcro window in the backpack so that the backpack may be zipped up with the cables connected to the control unit.
7. Attach one end of the parallel cable to the back of the laptop and the other
end to the control unit. Be certain to feed one end of the cable through the
velcro window in the backpack.
Performing a Measurement with the RAMAC GPR
Nominal velocity is 10 cm/ns (0.1 m/ns). Thus, if you want to investigate 1 meter deep, and remembering you have "two way time" and time=distance/rate, you will need:
(2 meters of travel)/ (0.1 m/ns) = 20 ns of signal per meter of investigation.
1. Record the start point of the desired line with a GPS unit.
2. Measure out the distance of the desired line.
3. Record the end point of the desired line with a GPS unit.
4. Turn on the power to the laptop
5. Turn on the power to the transmitter and receiver electronics (power switches
located on side).
6. Turn on the power to the control unit (power switch is located on side of
unit). At this time, the three lights on the control unit and the lights on
the electronics should be flashing.
7. Double click on the icon for the Groundvision software to load the program.
8. Click the Start (F5) key in the menu to create a new measurement. In the
dialog box specify the name of the file, the directory it is to be saved in,
the trigger mechanism, the antenna type, and then click the Settings button
on the dialog.
9. In the settings dialog box, make sure the antenna separation is correct for
the antenna type being used, set the desired trig interval, set the number of
stacks to 8. Then, click the Search for Time Zero button two to three times
so that the first arrival will occur near the top of the trace window. Also
make sure to collect only enough signal (total time) to cover the depth of interest.
Then click OK.
10. When ready to begin the measurement, click the Start Measurement button.
11. Collect data along the desired line.
12. When ready to quit the data collection, click the Stop (F6) button.
13. Close the window for the measurement data. This is to ensure that data collection
does not resume with the current file if the Start (F5) is accidentally pressed.
1. Access the Filter Manager Dialog Box. This is done by first going to the
Radargram menu and selecting Filter.
2. Highlight the DC Filter option and click Add.
3. In the DC Filter dialog, typically, select a point below the direct wave,
and click OK.
4. Highlight the Band Pass Filter option and click Add.
5. In the Band Pass Filter dialog, maintain the default settings, which should
sandwich the central frequency, and click OK.
6. Highlight the Time Gain Filter option and click Add.
7. In the Time Gain Filter dialog, in the left window, adjust the red highlighted
area so that it is just below the input wave pulse. Then, alter the linear gain
and exponential gain. Start with the exponential gain set approximately ten
percent less than the linear gain. Also make sure that the newly gained signal
in the left window does not have its extremes outside of the window. Once you
are satisfied with the gained signal, click OK. This takes some experimentation.
8. Highlight the Subtract Mean Trace option and click Add. Decide if
this helps or hurts.
9. In the Subtract Mean Trace dialog, click Total Average as the subtraction
method and click OK.
10. In the Filter Manager Dialog Box, click OK to see the newly filtered data.
11. If the data needs to be filtered again for better results, remove all the
filters and start over.
1. The laptop brace will come loose unexpectedly and start to drop the laptop.
2. The fiber optic cables become easily hung-up on brush or start to get pulled
under the antennae if they are too low to the ground.
3. Data collection will suddenly cease with the error "Communication Interruption"
if the unit undergoes too much vibration. This problem was encountered when
walking with the unit and also when attempting to use the unit with a four-wheeler.
1. Unable to operate unit in areas of heavy brush due to the lack of maneuverability
of the unit and also the increased risk of snagging the fiber optic cables.
2. Laptop battery life is approximately 2.5 - 3 hours.
3. GPR battery life is approximately 6 - 8 hours. NOTE: The battery life range
is an estimate.
4. Recharge time for one set of GPR batteries is approximately 8 hours.