What do you think about this 'point of view'? RE: The HammerHead

[Qiaozhi]

The second sample (HH1) is used to remove the Earths magnetic field. To cancel ground mineralization the detector would need 3 or 4 samples.

Both the HH and the Surf-PI have a second sample located much later in the pulse cycle, at around 200us. Since the target cycle has substantially died away after 200us, and the signal due to the Earth's magnetic field is relatively constant; subtracting the second sample from the first will remove the Earth field signal.

You can use a similar technique to provide ground balance, but in this case the second sample is much closer to the first sample, with something like 10us to 20us separation. However, this is a little more tricky than the EF elimination process, as the amplitude of the second sample is lower and needs to be amplified to match that of the first sample. You can either do this by increasing the gain in the GB sample channel, or increase the sample pulse width. Also, don't forget that the EF signal needs to have the GB sample subtracted as well, otherwise the EF elimination will be compromised. This technique does reduce the depth of the detector, but allows it to be used in ground conditions where you otherwise would find it impossible to hunt. The final drawback is the "hole" in the conductivity response that you may have heard about. Any targets that fall within the conductivity window created by the GB subtraction technique will also be rejected.

[mickstv]

Both the HH and the Surf-PI have a second sample located much later in the pulse cycle, at around 200us. Since the target cycle has substantially died away after 200us, and the signal due to the Earth's magnetic field is relatively constant; subtracting the second sample from the first will remove the Earth field signal.

You can use a similar technique to provide ground balance, but in this case the second sample is much closer to the first sample, with something like 10us to 20us separation. However, this is a little more tricky than the EF elimination process, as the amplitude of the second sample is lower and needs to be amplified to match that of the first sample. You can either do this by increasing the gain in the GB sample channel, or increase the sample pulse width. Also, don't forget that the EF signal needs to have the GB sample subtracted as well, otherwise the EF elimination will be compromised. This technique does reduce the depth of the detector, but allows it to be used in ground conditions where you otherwise would find it impossible to hunt. The final drawback is the "hole" in the conductivity response that you may have heard about. Any targets that fall within the conductivity window created by the GB subtraction technique will also be rejected.

I've had some success with three samples, one short sample the a long GB sample then another sample to cancel the EF But this method or the other method using all equal samples with more gain on the GB channel, all suffer from the electronic hole problem.

I've even tried multiple period TX pulses, all that happens is the hole moves to a different conductivity range.

[jladre]

Im interested in barracuda.. can we build it without oscop? If yes where can i buy the kit?

[kt315]

barracuda cover

[satdaveuk]

If you don't have access, or and have not the knowledge to use precision equipment such as a scope then you will not and never will end up with a precision built project, However you can purchase a out the bag DIY kit version from Silverdog which are very reasonably priced and according to some on here works reasonably well , his details are published here in Geotech.

Regards

[jladre]

Tnx a lot sir...