DX-300 – DIVER HELD MAGNETOMETER
User Manual
7
WITHOUT THE RUBBER SEAL CAN PERMANENTLY DAMAGE THE
SOCKET, WHICH MAY CAUSE THE CONTROL UNIT TO FLOOD.
Note: The charger plug can only be inserted one way round due to the polarising
pin
.
4. Plug the connector on the Bonephone (or headphone) lead into the PHONE &
CHARGE socket and screw down the collar as above. NB. For testing on land the
headphones – if available - are much easier to work with.
5. Locate yourself to the centre of the testing area, hold the Sensor Probe at full
arm’s length from your body, pointing down at about 45 degrees, and switch the
unit on by rotating the POWER – SENSITIVITY control to the LO position. If a
continuous sound is heard immediately, the SET AUDIO control should be
rotated one way or the other until the audio threshold is reached; this is indicated
by a low frequency ticking sound in the Bonephone/Headphones. Note. The SET
AUDIO has a full 10 turns of rotation to give it good resolution of setting. There
is a “central point” where you will achieve the low frequency ticking sound,
turning the SET AUDIO control either way from this point will result in an
increase in the audio output.
Note: The SET AUDIO control is a 10-turn potentiometer. Do not turn it past its
stop point in either direction or permanent damage will result. The audio threshold
should be somewhere in the middle of the 10 turns, so just start turning one way
until you either reach the audio threshold or the stop point of the control. If you
reach the stop point without finding the audio threshold, start turning the other way
until you do. Once you have found the audio threshold the first time you test the
unit, the SET AUDIO control should be in the near vicinity of the correct location
for future uses, so you will normally just need to tune it back and forth a few turns
unless someone has turned it away from this setting.
6. Once you have achieved the audio threshold adjustment, turn the POWER -
SENSITIVITY control to HI. You will probably have to make minor
adjustments to the threshold setting when you switch to HI. Once you have the
threshold set to the low frequency ticking, you are ready to begin testing. Test the
operation of the DX-300 by walking slowly towards the target with the Sensor
Probe pointed down at about 45 degrees rather than vertical to increase the lateral
sensitivity. As the Sensor Probe is pointing in the direction of a target, you
should hear an increase in the audio output. Walking passed the target at a
distance of about 2 metres (6ft) you should get a peak in the audio as you pass the
target then a gradual reduction as you walk beyond the target.
7. Carry out a subsequent test with the X HI range setting – readjusting the audio as
required, this should give an increase in the detection range. Note this range
requires the operator to hold the sensor as steady as possible to avoid any changes
due to angular or rotational effects rather than target responses.
