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4) Measuring noise
As the levels of outside noise varies between job sites, the range of transmission will change.
For this reason it is useful to take a reading of the noise level of the jobsite before beginning.
Ⅰ) Perform calibration as described in section 3) - Depth Correction (calibration)
Ⅱ) Remove the batteries from the probe so that there is no signal coming from it.
Ⅲ) Take a depth measurement.
Confirm the measured depth on the locator of the jobsite at which you will be using the unit.
Ⅳ) Calculate the transmission range of your site based on the measured depth.
Formula: Transmission range = Measured depth × 0.8
（
e.g. for a measured depth of 30.0 m, the transmission range would be 24.0 m
）
The frequency and magnitude of noise varies depending on the jobsite.
For example, strong noise may be emitted from nearby power transformers or the lights from a large retail
store.
For users with multiple probes, please measure the noise of your jobsite and select the probe that is best suited
for that environment.
Features of each probe type
· VPL-G7P: Frequency – 38 kHz
When the noise level is good, this probe has the longest range.
· VPL-G9P: Frequency – 9.5 kHz
This probe has the lowest frequency, making it less susceptible to
interference from metal plating or other obstructions.
· VPL-G4P: Frequency – 14.4 kHz
This is a more balanced, midrange probe.
26.5m
VPL-G7P
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Take a depth reading
Check the settings of the probe
