Induction Balance VS VLF

Can someone please explain the differance between Induction Balance and VLF?

Rather than writing a lengthy reply, and all the inevitable questions to follow, I first suggest getting a copy of "Inside the Metal Detector" by Overton and Moreland.

It's a wonderful mix of theoretical, practical, historical and explanations of terms...and more.

Also, there’s this - Understanding the PI detector by Reg Sniff...

[web.archive.org]

Rick Kempf
Gold Canyon AZ- where there is no gold

Also, I noticed you had asked the same question in the Golden Sense thread, and I answered (what I hope) was the question you were asking.

To follow-up that answer:
In it's simplest terms, IB (induction balance) is a precise term referring to a constant field method of energizing a field between a primary and secondary (transmit and receive) coil.
That's opposed to a method of sending a pulse, then letting the field collapse and listening for a response (PI).

The terms such as VLF and TR are more nebulous terms that evolved to explain the different methods of ground balance...and sometimes discrimination methods.
They are not precise, and in fact are not entirely accurate...they had some influence form the marketing guys.

In short VLF and TR machines are all IB machines...but all IB machines are not necessarily VLF.
Historically, PI machines are not IB, nor are IB machines PI.

Hope I helped,

mike

Yes I did ask this question on multiple post that way I can get different answers and theory's from many people.

Thanks for the info.

Thanks Mike for the book info....just ordered one



Edited 1 time(s). Last edit at 02/03/2019 10:17PM by dewcon4414.

Mike is largely correct.

"IB" refers to the coil design, nothing else.

"VLF" strictly means the frequency range of 3kHz - 30kHz. However, it's common to extend the term beyond that, i.e. the White's Coinmaster V Supreme, Fisher Goldbug 2, and Minelab Eureka are all considered "VLF."

"TR" originally referred to the coil design as well, though most people apply it to detectors which have separate transmit & receive circuitry (unlike the BFO, which did not).

Back in the 70's when VLF emerged, it was a shift from high frequency (100kHz) to the VLF range (5kHz) with the addition of ground balance. Many detectors had a selection for "TR" mode and "VLF" mode, the distinction being VLF had ground balance and TR did not, and discrimination was available only in TR mode. When VLF-disc was introduced, the TR mode faded away. That's the distinction I prefer for TR vs VLF: regardless of frequency, VLF has ground balance.

Thanks for the info guys.

Geotech Wrote:
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> Back in the 70's when VLF emerged, it was a shift from high frequency (100kHz) to the VLF range (5kHz) with the addition of ground balance.

Interesting that it started at 100kHz, went to the VLF range, and now, gold and relic hunters in iron seem to be favoring higher kHz again.

Cal_cobra Wrote:
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> Geotech Wrote:
> --------------------------------------------------
> -----
>
> > Back in the 70's when VLF emerged, it was a shif
> t from high frequency (100kHz) to the VLF range (5
> kHz) with the addition of ground balance.
>
> Interesting that it started at 100kHz, went to the
> VLF range, and now, gold and relic hunters in iron
> seem to be favoring higher kHz again.

It's funny you say that back in the day I had an Orion 3 (100 kHz) made by Wilson of the Wilson Neuman fame after they split. I found some good stuff with that detector, that I know many detector coils passed over.