300 coils prone to EMI?

[TabWhisperer]

I had a 300 coil laying around (I didn't have a compatible machine for a while) and decided to try it out on a M6 I just picked up. The ear is stamped SS 0378 (I think original stamping for V rating) and it seems to work correctly otherwise. I don't remember 300 coils being real subject to EMI noise but this thing chirps like crazy when the gain is around 80-90. It quiets down when the gain is turned down to around 50. The stock coil gets EMI chirps just a very tiny bit in the same area with the gain turned all the way up but runs normal around the 80-90 range.

I also noticed when pinpointing a surface target using the audio the coin would be just touching the left edge of the inside circle when it was loudest, not centered like most of Whites coils. Does this coil have problems?

 

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[christo000]

I myself dont know about that coil I even looked in the accesory guide didnt have it in there but ya its funny more & more talk on the m6 from one post I was wondering where they all went lets c if the dfx's come out I just mentiond those & there good to

 

[a4wdguy]

I'd say it does not have problems. Larger coils are more sensitive to EMI than smaller coils, so what you are describing doesn't seem out of line. Even though 90 is the preset position for the 950 coil, I have been able to run over 100 with no issues for the most part. Additionally, pin pointing to the inside edge of the inner coil translates to only a couple inches off from center. Again, that doesn't seem too bad for a large coil to me. However, I've never tried my 300 on my M6, so can't be sure how it would act. At this point, I'd assume the coil is good, but try to find an opportunity to try a different 300 to compare them side by side.

 

[DizzyDigger]

Are you sure it is EMI and not just hotter soil conditions?

Could be that the coil is picking up some spurious emissions from the
detector itself, or it is not properly calibrated to the machine and freq.
of the unit you have it on.

Are you near any low-freq, sources? Detectors operate are very low frequencies,
so if you are getting EMI on that coil it's coming from a rather powerful magnetic field
you are relatively close to.

 

[chinchilla]

it's normal, larger coils seems to act like a radar dish with EMI. there are places I can't even use the 950

 

[Sandman]

Coils are calibrated for one model of detector and to use it on another even if the pins match is anyone's guess what your results will be.

 

[a4wdguy]

The White's 300mm coil can be used on the M6, MXT, DFX, and even the V series detectors. The caveat is that a coil (any coil) that isn't 'V rated' may not function at higher gain.

 

[TabWhisperer]

Thanks all. I'll keep running it. I figured if they were normally a quiet type of coil I would ship it off to Whites to look at. I have noticed some detectors in this school yard can get a little noisy. There are nearby cell antennas, power lines and a bunch of wireless stuff in the school. I was just surprised at how noisy this particular coil was. I had used another 300 coil in the past on a V3i and don't remember it acting like this one and wanted to do a reality check.