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QED and EMI
If you are suffering from EMI when out and about in the goldfields (i.e. getting unwanted wavy type
responses with the coil stationary), then:
1. Drop THS-A down to around 30, and then
2. Drop THS-B as far below NULL as you can get.
A medium/high/very high THS-A (say anything above ~45) will pick up more EMI than when at ~30.
So when you drop to A=30, and you drop B as far as you can below NULL you will find that the
effects of EMI will be muc
h less and you’ll be able to detect more or less normally.
If you still get some EMI coming through, then increase THS-B more towards NULL.
This works for atmospheric generated EMI. Of course, if you have an electric drill operating very
nearby, then no amount of setting changes will eliminate it.
Ground Balancing with the latest 2019 upgrade
For those lucky QED owners with the latest 2019 upgrade, there are two methods to initially
determine whether to go up in numbers or down to GB.
1. Listen for the tone as you lower the coil to the ground and determine whether it is:
•
A
high (rising) pitch, in which case you’ll need to go down in numbers, or
•
A
low (falling) pitch, in which case you’ll need to go up in numbers
2. Use the AGB to determine which way it wants to go, up or down in numbers
•
Once you’ve got the direction, then very, very slowly bob the coil whilst depressing the
appropriate (up or down) button.
•
You will notice that it will get quieter and quieter as you approach GB, at the quietest point
release the button.
•
Bob the coil to check the GB and if needed incrementally adjust to get a perfect GB.
Manual Ground Balance (MGB)
Two things to remember when performing a MGB:
1. Always allow the audio to recover before moving the coil back down to the ground, and
2. MGB slowly; take your time and you will get a much more precise ground balance, for example,
the minelab ground balance (bobbing) speed is way, way too fast and you will probably not be
able to ground balance. Slow it down; find the rhythm based on the audio recovery time and you
will find the MGB works perfectly.
Summary of Contents for PL3
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