101
GSM19 Series Magnetometers - Version 7
GEM Systems, Inc. Advanced Magnetometers
For more technical information, visit www.gemsys.ca
C3. STARTING A READING
Press
A-start
to start the survey. The VLF readings are presented as on the following screen
SCREEN C7
24.0 kHz 005.6 pT
i-022.1% o+014.2% p 053 v 024
A-menu 1-repeat (same position)
L00100N S00112.50E
Each Station will have 6 Values displayed:
Frequency in kHz.
b: Field strength in pT
i: In-phase component as a percentage of the field strength
o: Out-of-phase component as a percentage of the field strength
p: Horizontal component - coil axis parallel to the operator’s direction, arbitrary scale
v: Horizontal component - coil axis at the right angle to the operator’s direction, arbitrary scale
The last line displays the position coordinates in the form of the current positioning system.
When conducting the survey with the VLF option on the GSM-19, the quality of the incoming
signal can be effectively determined by the
field strength
shown in the upper right corner of the
screen. This value is directly proportional to the strength of the incoming signal. A field strength
reading above 5pT yields excellent quality results. Below this level, the readings still give useful
results, although of lesser quality. A field strength reading of less than 0.5pT indicates a VLF
signal so weak, the results are not useable.
To conduct a useful survey of an area, you should tune into a station with the highest possible total
electromagnetic field reading.
To determine the field strength of the stations you can use the
Scan
option.
The
Scan
option gives you a general view of the available VLF spectrum. The entire VLF range is
scanned and all stations of sufficient strength are displayed along with their signal strength in pT
(or mgamma).