VLF Concentric Vs DD Coils

[Argyris]

Thanks Steve, nothing compares to real time testing, so I completely agree.

I'm thinking of pulling the trigger for a Multi Kruzer for shallow underwater use (instead of risking again with my Nox 800 which drowned and got fixed)....I've found an offer from a Makro dealer who offers me one additional Multi Kruzer's coil for free in the package (stock is 11''x7'' DD...and he offers as an extra for free either a 9.5''x5'' DD, or a 7'' concentric)...so I was trying to decide which one should I choose as best for underwater in salt (I need a small one anyways). 

I think I'll choose the small DD....must be a safer option

[kac]

Salt water I have found the narrower dd more stable than a wider one and a dd in general more stable than a concentric. Comparing the 2 DD's I have for my Multi Kruzer the stock 7x11 is a little more stable towards the wet sand and doesn't false when hit with the surf but the 12" is deeper for beach combing. It does false when hit with the waves but that could very well be from the coil cover having water trapped behind it.

Having a smaller concentric for the Multi Kruzer is really good when you have a lot of flat iron like washers, steel bottle caps etc in trashy parks where they will come in closer to the iron range. DD coils will ring in flat iron up in the higher numbers but not all is lost if you keep iron audio on you can use the nose or heal of a dd to see if you get that really awesome grunt iron makes.

[Argyris]

13 minutes ago, kac said:

Salt water I have found the narrower dd more stable than a wider one and a dd in general more stable than a concentric. Comparing the 2 DD's I have for my Multi Kruzer the stock 7x11 is a little more stable towards the wet sand and doesn't false when hit with the surf but the 12" is deeper for beach combing. It does false when hit with the waves but that could very well be from the coil cover having water trapped behind it.

Having a smaller concentric for the Multi Kruzer is really good when you have a lot of flat iron like washers, steel bottle caps etc in trashy parks where they will come in closer to the iron range. DD coils will ring in flat iron up in the higher numbers but not all is lost if you keep iron audio on you can use the nose or heal of a dd to see if you get that really awesome grunt iron makes.

Many thanks Kac, that's what I was looking for...! Since I have the option for an extra free coil from the dealer, I'll go with the smaller DD for salt water use. Later I may add a concentric also for the reasons you mentioned when inland.

[kac]

Will the dealer swap that coil out for waterproof headphones?

Note on the Nokta waterproof headphones you need to crank the audio to 10 to hear it. Waterproof headphones in general have poor audio because of the speaker type.

[Argyris]

22 minutes ago, kac said:

Will the dealer swap that coil out for waterproof headphones?

Note on the Nokta waterproof headphones you need to crank the audio to 10 to hear it. Waterproof headphones in general have poor audio because of the speaker type.

Hmmm.....free waterproof headphones would be a really usefull alternative vs the free extra coil...it didn't cross my mind!

I will definitely ask him! 

Thanks!

[ODIE]

Any  input from White's V3i owners would be appreciated.

gary

[☠ Cipher]

On 1/26/2015 at 11:36 AM, Steve Herschbach said:

Finally, depth is more related to coil width than coil length. Think of a 5" x 10" coil as a stretched out 5" coil, not as a skinny 10" coil. That is why when listing elliptical coil sizes you will often see me putting the small number first. Marketers do it the other way around so you tend to think you are getting more than you are. A truer picture can be had by comparing the total area of a coil, one to the other, but for quick and dirty comparisons, comparing by width will give you a more conservative idea of comparative coil performance, than comparing by length.

This explains why we see so little depth gain with coils like 13”x17” and 12”x15” over their 11” round counterparts. The dimension that matters to depth rather than coverage is only 1”-2” larger than stock. So when someone asks on the equinox for example, which is deeper, the 12”x15” Minelab or the 15” round Coiltek, it should be the 15” round depending on the target as well of course 

[phrunt]

That and the fact detectors seem to have a depth limit where putting on a longer coil adds no extra depth at all or very minimal noticeable depth improvements, and this seems to be the case with comparing the Equinox and 12x15" coil and the 15" Coiltek.  It was the same with my T2 as well, I wasn't able to get any extra depth using the 15" trash can lid coil over the 12"x13" Mars Tiger coil.

[☠ Cipher]

This has me dubious about the Deus 11”x13” coil as well. It is not uncommon to see an awful lot of these for sale and complaints that they gained no depth over the 11” round, only coverage, which made the unit nose heavy. The Deus II is one unit I would love to see an actual 13” round coil for, but I’m guessing we will never see it. It looks like all they have in store for us is another 11”x13”