Double D Null Question

[Kurt]

Hi, New to post. I have three 10" Double D coils. When held in the air two coils null at suggested gain 8 and the third that I just purchased suggests a gain of 15.
All coils tested at the same site. I contacted White's and was told that anything 8 and above is accepable and there is nothing wrong with the first two coils.
The 3 coils are V rated. Any thoughts?

 

[ak_1234]

In the air (NOT on the ground) if you crank your gain to 15, and turn TxBoost on, does your machine overload? If you get the overload groan, then your coil is bad. (Make sure there is no metal by your loop...)

Do you notice a significant difference in performance between the loops (does the loop with the suggested gain of 15 read deeper than your other 2 coils? Are the other 2 a lot noisier as you sweep compared to the one that recommends gain of 15)?

 

[Kurt]

Yes in the air. I have not had the time to try the new coil that nulls at 15. One of the two coils that nulls at 8 came with the Spectra and the other that nulls at 8 rides on one of my MXTs. The coil which was just purchased that nulls at 15 was intended for my other MXT. I have had no issues of erratic behavior or falsing.
I was concerned that the V3 might not acheive it's full potential with the coil that nulls at 8 and of coarse the coil that now nulls at 15 will ride on the V3.
I live in the Sierras and have not used Boost due to the soil conditions ( If you can call decomposed granite soil ) I will try boost and test all 3 coils.
Perhaps I do not fully understand nulling and it's impact on performance.

 

[ak_1234]

Yes in the air.

I'm confused - did they give the overload groan with Tx Boost on, and gain set to 15 in the air? If so, then the coil is bad (at least for the V). If there isn't any overload, you have good coils and not to worry. The recommended gain was calculated for an arbitrary percentage of used signal (10%). Could have been higher (and probably should have been). But, it is not a loop test.

I have not had the time to try the new coil that nulls at 15. One of the two coils that nulls at 8 came with the Spectra and the other that nulls at 8 rides on one of my MXTs. The coil which was just purchased that nulls at 15 was intended for my other MXT. I have had no issues of erratic behavior or falsing.
I was concerned that the V3 might not acheive it's full potential with the coil that nulls at 8 and of coarse the coil that now nulls at 15 will ride on the V3.
I live in the Sierras and have not used Boost due to the soil conditions ( If you can call decomposed granite soil ) I will try boost and test all 3 coils.
Perhaps I do not fully understand nulling and it's impact on performance.

If they're not overloading, they are good and you shouldn't see any degradation in performance.

 

[Kurt]

Thank you ak 1234. There is no overload groan with Tx Boost on.