Eliptical vs Round

[Ism]

There are some areas I hunt by power lines (transformers in particular), that are very difficult because of EMI.
I'm talking about 100 ft away that is fairly brutal on the ears (especially when I set the detector down to dig).

It is generally accepted that eliptical coils are less affected by noise than round coils.
I'm curious about the EMI factor between the two. Is it significant or not enough to notice?

 

[Andy Sabisch]

Not sure the coil shape will have any noticeable impact on the EMI impact you experience. A larger coil may be more susceptible.

A change in the operating frequency may address this - I have found that using on offset (+ or -) can correct or at least minimize the impact of EMI

Andy Sabisch

 

[Ism]

Thanks Andy, I often adjust the frequency when working in those areas as well as sensitivity.
Lower reactivity also makes quite a difference in reducing the noise.
It was a point of curiosity in consideration of the larger elliptical coil for the farm field hunts.
Some of the areas have power lines running through them about 300 ft from the road, not just at the road.
Really screws up some prime hunting.

 

[Andy Sabisch]

Again, not sure how much the coil shape will impact EMI versus other adjustments or the overall coil size does.

Lower frequencies tend to be less effected by EMI than the higher ones . . . . I tend to drop to 8 or even 4 when working under high voltage power lines. Offsetting the frequency may help a little - see if a +1 or -1 setting helps

Reactivity - the higher the setting the more susceptible to EMI the detector will be.

Increasing the Silencer setting can get rid of some of the chatter so try bumping it up to 3 or 4 when you get into a bad area

Sensitivity is another feature that lower can help . . . but be careful as the drop in detection depth increases as you go lower; i.e., once you get below 85, each number produces a greater drop in detection depth

Hope these help . . .

Andy Sabisch

 

[Ism]

Andy, funny thing is I have tried lower freq's under power lines. Everything is noisier than 12khz.
I've even tried offsets. I haven't changed silencer mode, so I will try that when I get a chance.

 

[Hobo lobo]

A DD coil may be slightly less sensitive to EMI than a concentric, but I don't think a round coiln is more prone to EMI than a eliptical.

 

[Ism]

A DD coil may be slightly less sensitive to EMI than a concentric, but I don't think a round coiln is more prone to EMI than a eliptical.

Maybe not, I read it somewhere about elyptical vs round but that was for concentric. Now I can't find it.