Minelab CTX 3030 Detecting Forum

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Re: EMI problem
Posted by: Geobound
Date: January 27, 2019 08:42PM
Ben Town
Noise Canceling
This is one of those things that has some fuzzy edges.
At one of the boot camps a few years back this was disscused and we were told to put the coil on the ground and NC.
It’s been awhile but the reasoning was you don’t hunt with the coil a foot off the ground why NC there , NC on the ground where you hunt.
So I remember starting out NCing a foot off the ground and after the class on the ground.
I’ve got major power lines about 200 yards from my house and really haven’t noticed much interference , I think I’ll give this a look when things warm up and see if it makes any noticeable differance when I play around in the test garden.
It makes sense to NC where you hunt but when it comes to the internal workings of the CTX who knows

The information given on Noise Cancel that says to touch the coil to the ground is incorrect. Below you will find the instructions from Minelab.

Perform Auto Noise Cancel
Auto Noise Cancel is recommended.
1. Make sure there are no large targets or obvious sources of EMI close by, and hold
the detector coil 12 inches (30 centimeters) above the ground (Figure 17). **Figure 17 is the attached picture below**
2. From the Map or Detect screens press the Noise Cancel button to initiate Auto
Noise Cancel.
Automatic channel selection will commence and a progress bar will be displayed. Keep the detector still during the selection process, which may take up to 30 seconds. Press the trigger to terminate Noise Cancel at any time.
When the progress bar reaches 100% it will disappear and an audio signal will convey that Noise Cancel is complete.
12” (30 cm)
Figure 17 – Correct detector position for Noise Cancel
Manual Noise Cancel
The Manual setting allows you to manually select and listen to each channel for the least interference.
To manually adjust Noise Cancel:
1. Make sure there are no large targets or obvious sources of EMI close by, then hold
the detector 12 inches (30 centimeters) above the ground (Figure 17). **Figure 17 is the attached picture below**
2. Open the Noise Cancel Quick Menu and use the down arrow button to highlight
the Manual option. Press Select.
3. Press the left or right arrow buttons to select a channel. Pause and listen to the interference coming from the detector. Keep the detector still during this process.
4. Once the channel with the least interference has been found, press the Select button to save and exit the menu.

Hi Ben,

Funny I just posted a reply about my thoughts on this in this thread here.......,2476524

In short I agree with the logic of doing the NC on the ground, but it isn't always ground interference that's the problem.

In year one I did the NC just skimming the ground, and year two I did it about 12" off of the ground. I'd be hard pressed to notice any significant difference, and that's for hunting in the city or the country. Water hunting is a whole new ball game. LOL......

The few times that I was in an area with high EMI (above ground), I found holding the machine at the 12" mark to make a bit of a difference. There was still the electro magnetic interference going on, but it seemed to soften it some.

I guess the only way I would know for sure would be to do a test with each method, and a few purposely buried targets in the same EMI location.

This could be a new spring project for me to try out...........far too much snow where I am right now to be out detecting. LOL.......

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