Noise cancellation?

[mlitty]

I'm new to the X-Terra 505 and loving it. I'm on my third read-through of Mr. Horton (Digger)'s book, "Understanding Your X-Terra" and I'm watching all of the videos that I can find on the detector.

My question is about Noise Cancellation. I know what it does, canceling out electronic interference from external sources. I know why it's important to avoid outside signals from corrupting the detector signal. And I know which buttons to push to make adjustments to the Noise Cancellation. I don't understand WHEN to make the adjustment and how I know if I'm on the right channel.

With threshold, there is an audible tone one can hear when making adjustments.
With ground balancing, there is a tone that indicates if the balance is too high or too low.
With sensitivity, one can listen for chatter and back down to a working level.

With Noise Cancellation, all I hear is silence, even when I'm standing next to a power line across the street from a terrestrial radio broadcasting tower. The Minelab video says, "find the quietest channel to remove most of the emi interference." What am I listening for that would indicate interference? How do I find "the quietest channel" when everything is silent? How would I know that I'm on a noisy channel?

Thank you for your help.

 

[Old Longhair]

If it's quiet, then you have a clean channel.
If the machine seems "chatty", especially when not moving the coil, then you need to pick a different channel.

 

[mlitty]

If it's quiet, then you have a clean channel.
If the machine seems "chatty", especially when not moving the coil, then you need to pick a different channel.

So it's really the same feedback that I might hear if the sensitivity is set too high or the ground balance is off? By process of elimination then,

1. Set Ground Balance
2. Set Sensitivity
3. Set Noise Cancellation

If I can't find a quiet channel, back down sensitivity and try noise cancellation again, repeating until the chatter has died down?

 

[michaelosully]

Yep!
Just to illustrate, yesterday I went out to a new spot. I usually detect old campsites, river crossings, and other very remote locations in the middle of nowhere... so much so that I've gotten into the bad habit of not even paying attention to 'noise cancelling'. In this deep canyon along side a river bank I fired on the 705 and couldn't get it to stop chattering. I even went so far as to pull the coil cover and clean it good to see if it would resolve the problem, but it made no difference.

I set down on the tailgate to think through the situation and it hit me ... 'look up STUPID'! Yep, right there in middle of nowhere, probably 300' overhead were two electric transmission lines (one four line running North South, and below that another 2 line running East West). I did a quick noise cancel and solved the problem. Was then able to return to my other bad habit of 'diggin stinkin lincolns' .

Oh well, it was a good day!

Good luck with the 505, I've owned one and thought it was great...only reason I moved up to the 705 was for the prospecting mode option.

 

[Old Longhair]

I usually pick a clean channel before doing anything else. It makes everything you do afterward more accurate if there is no interference.

 

[mlitty]

Thank you for the info. It's exactly what I was looking for.

I guess that I just haven't run into a situation in which noise was an issue. I will keep it in my setup rotation though, just to keep the habit going.

Also a good reminder to clean my coil cover now and then.

 

[mapper65]

I usually pick a clean channel before doing anything else. It makes everything you do afterward more accurate if there is no interference.

Same here.

 

[brianincnb]

This is my standard drill order when I power mine on at a new site:
1. Set Noise Cancellation
2. Set sensitivity to about 10-12
3. Set Ground Balance(GB)
4. Reset sensitivity up to what I'm confortable with and that is stable ie: > 20
5. Detect away and checking GB every 10minutes or so..