SE Noise canceling - 11.8" or detecting height?

[king-ghidorah]

I was perusing through older threads and a user mentioned this point that I will say out here verbatim in a PM that he sent to me.

We are told to do noise canceling at a height of 30cm (almost 12") when we first begin our MD session if you're doing auto.

But what he says makes more sense to me,

"Ive always ground balanced at detecting heights. Every thing affects balancing and it makes no sense to balance for noise at knee high when you are not detecting there."

AND

"Also if you encounter EMI from the ground would you noise cancel at swinging heights or 30 cm?"

This makes a lot of sense to me unless I am missing something here. So why are we doing this at 11.8"?

 

[Charles (Sabre)(Tx)]

I don't think noise canceling has anything to do with ground balancing. Noise canceling only refers to anything that might send out interference via RF waves...therefore the ground is exempt unless there is something in the ground that is emitting those type waves (maybe a burried dog fence wire?)

I've always thought you could noise cancel at any height or even on the ground as long as there wasn't any metal under your coil. Metal under the coil could possibly reflect the signal back into the coil while noise canceling.

Just my thoughts. Hope this helps. HH

Charles

 

[D&P-OR]

This is a subject that has been kicked around, debated, cussed, discussed over & over-and I guess it will continue to be until "the cows come in" (or they change the noise cancel system).---I used to noise cancel with the coil resting on the ground (while I put on my left glove).--I now cancel 12" above the ground.--If you were to ask me-does it make a difference?--My answer would be "I dunno".--I've done it hundreds if not thousands of times both ways and the end result seems about the same to me.--As pointed out-there can be variations in the ground & the atmosphere though.--They had a lengthy debate about this not too long ago & a Minelab rep. even got in it-I don't think any "do it this way all the time" was decided then either.-------Del

 

[king-ghidorah]

heehee. I guess you're right.

 

[Neil]

n/t

 

[jbow]

Doing a manual noise cancel. First I will do an auto noise cancel then swing the coil over an area a few times. Then I will try changing in manually. I usually will find a more stable setting, especially in bad ground. Yesterday the machine was setting itself on 10 but it ran quieter on 3 and 4.

J

 

[mattockman]

n/t

 

[dewcon4414]

Unlike the Sov GT which sets its freqs every 1.5 kHz the Explorer sets its 28 freq's randomly based on the noise cancel. I know the DFX noise cancels at waist height but has a heck of a problem with EMI. I still found noise canceling at swing height worked best for ME. There is a magnatic influence from the mineral in the ground in some areas which may well be why the height of noise cancel. Since i travel full time i do get a chance to hunted all kinds areas and still havent found a difference. I also noticed less noise manually noise balancing... but im not sure how its affecting those random freq's. It may affect your depth or the type of targets you find. An example would be moving the freq's more toward 1 kHz vs moving it toward 100 kHz.