Tuning The Coil To The Detectors Electronics

[Bohemia Miner]

I looked for this topic before posting so I wouldn’t duplicate something that’s already been discussed.  Nothing came up.

I remember back in the day, you used to have to send the coil in with the detector when having it repaired so they could also tune it (the coil) to the machine.  This was on those with Auto GB.  According to Vince Gifford at Tesoro, Manual GB didn’t care because you could manually “tune” it.

I was also told that as a result, accessory and aftermarket coils won’t work as well as the original coil that came with it for that reason.

Is this still true?

Thanks!

Walt

[Steve Herschbach]

Yes, back in the analog days detectors were often tuned for the coil they came with (not the other way around). It was a functional set, and tuned as such. Any accessory coils may or may not have varied enough to matter. In most cases they did not, but for something like a Gold Bug 2 on the tiniest gold, it might. I did send my old GB2 back to Fisher once to get properly tuned up for a new small coil.

New digital machines, not so much, or just a flat no. Equinox coils by Minelab, for instance, have some amazingly tight tolerances. But you get some aftermarket coil for a Garrett AT Pro, for instance, I’d bet stuff still can vary. Minelab has gotten really anal about controlling aftermarket coils, and this issue has a lot to do with that. The PI world in particular is still a Wild West show. And we have the case of the GPX 6000, where OEM coil failures have been surprisingly common for coils made by a top manufacturer in the 21st century. It’s not outright failure that is the problem, but subpar performance.

I think a substantial number of detectors made by all brands have varying numbers of functional coils that are delivering substandard performance. This in turn fuels misguided detector comparison videos, and outright internet arguments. It may be the biggest sleeping dog in metal detector land, but nothing short of a very expensive, independent, cross brand, scientific test regime will ever reveal the truth.