GB Numbers

[Danno]

Why do manufactures make it so complcated when displaying GB Numbers as opposed to discrimination numbers.
Take the Deus for example the disc runs from -6.4-99 which includes the ground, the GB system though has a completely different numbering system.
Surely it would be easier to have one scale so you know where ground is set in relation to your disc setting?

Whites were the same on the XLT/DFX, disc was -90 - 0 - +90 but GB was 0-255.

[Skippy]

Ground balance covers a different range to Disc range, for one thing. Ground phases go from 0^o to 90^o lag, whereas Disc range is from 0^o through to 180^o lag. Then there's the problem of scaling and resolution: GB needs fine resolution over the 0^o to 20^o range ( for soil/dirt), but not much resolution from 20^o through to 90^o ( saltwater). Whereas Disc needs less resolution from 90-110^o lag (foil range), and more resolution for 160^o - 180^o lag (large silver/copper coins).
So it's all maths tinkering to stretch and squash the scales/ranges to make them seem sensible, and fit on a '88' or similar display.
And the result is every manufacturer and seemingly every machine on the market end up different. Not to mention things like the Deus giving different readings for every operating frequency ( because it probably uses the same algorithm regardless of mode); then there's the GB on the Equinox - it runs at several frequencies, so presumably gives a different GB reading for each frequency, so how do you display one GB value?

[Danno]

Agreed that there needs to be finer resolution at certain ranges, I just think they over complicate what is displayed to the user. Resolution is easy to solve by just having decimal places between whole numbers on a certain range. Deus does do it for iron on the disc and GB but the scales are completely different.

The pic below shows it in simple terms, maybe i am just over thinking it.

[Skippy]

"I think they over-complicate what is displayed to the user"
Quite the opposite, they put some thought into displaying info in a simple to comprehend way. Though they don't always get it right.
Your attachment clearly shows the problem. Almost no-one wants 90 points of iron resolution. 10 or 20 points is plenty enough for most people. But for ground balance, in 'strong' soil/dirt, 0.1 degrees can seem a bit course. If I recall correctly, the Fisher F75 GB values have '90' to '50' covering phase lags roughly 0^o to 20^o, but the rotary shaft encoder actually takes 5 clicks per digit, so it goes in 0.1 degrees steps. [this is from memory, I didn't check the manual]
And the non-ferrous scaling is one of those juggling acts. The Yank coin-shooters seem to want to tell the difference between near-identical coins. European relic hunters are more interested in low-conductors, and want some resolution there, but don't want to distingush between big milled silver coins and slightly bigger milled silver.

[Danno]

Makes sense what your saying Skippy, thanks.

I'm I right in thinking the main difference between the F75 & T2 is the resolution on the iron disc, which would make sense on what you say about American coin shooting and European Relic hunting.

[Skippy]

I prefer the 'American Coin-shooting' scaling of the F75 for European non-ferrous relic hunting. The 40 points Iron range of the T2 is too large. If the F75 has 20 points Iron range it would be OK, it could be split into 4 blocks of 5 points for notch-related stuff. They could squash up the top 10 points ( 90 - 99) without any issues to compensate. Or ... be inventive, and extend the scale to 109 by displaying h0, h1,....h9 for 'hundred and 9'.
There's actually a fair number of differences between the T2 & F75, too many to bore you with... concentric coil options, notching, non-volatile settings memory, backlight, more modes.

Regarding your mention of using decimal points for GB or Disc: I personally dislike this, as the point is not easily visible, 2.5 or 25?