Made GasTracker - Page 13

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Things to know about the signal:
With distance, the signal will slowly decrease to a point where the values will be too low to be
good (between 20 and 30%). At this time, you have to switch to ‘Gain 10’; it will immediately
give you a better reading of the signal to continue the localization campaign.
Once you arrive to low values in Gain 10, it is time to disconnect your transmitter, and connect it
somewhere else farther along on the network.
The signal is supposed to decrease slowly, if it drops very quickly (like 88% to 3% at only one
meter, or three feet ahead) it can only mean three things:
- The pipe switches to metal (you cannot find metal pipes with the GasTracker™)
Solution: None. Metal does not vibrate. By the way, if the metal pipe section is
short, and if it goes back to plastic a few meters/feet ahead, you will certainly find
your signal over there.
- The pipe goes in a conduit (the signal is no longer sent through the ground)
Solution: None. The air between the top of the plastic pipe and the top of the
conduit cuts the signal. It is not propagated in the soil anymore.
- The pipe ends here (or makes a curve)
Solution: Go back to the latest known signal, and make a circle around it to check
if there is a curve in the pipe direction (see below). If not, it may signify the pipe is
stopped.
Compare what is comparable
Never compare two signals that are NOT on the same kind of soil, because their compaction will
certainly be different!
Example:
- 78% over asphalt is better than 42% over the same asphalt
- 52% over grass is better than 31% in the same garden
- BUT 42% over grass MAY BE better than 55% over asphalt BECAUSE of the difference in
soil compaction …
If the grass was as compact as asphalt, the result may have been 88% instead of the 42%.