Dave J. said:
.... I was hired in early 1981 to come up with the next advance which was motion discrimination, something White's already had. In 1982 we launched the 1260-X .....
I remember the era well. Was only a teen and early 20s at the time. But had started in the all-metal TR days of the mid 1970s. Quickly swept up into TR-discrimination (Ground-hog).
Then one day, about 1978 or 79-ish, we saw some dude swinging a detector like it was a golf club (very fast pendulum swing). We smuggly laughed at how stupid that guy must be. I mean ... duh ... everyone knows you got to creep slow and listen for the whispers, *right* ? Later we began to bump into a few more of these hunters (about 1980 by now). It was the Bounty Hunter SPD and the Whites 6000D series 1. Again, we smuggly giggled at their un-conventional swinging.
Until we began to see their show & tell at the club meetings. Eg.: silver in hand-fuls from parks that we were doing good to get a single silver at per hunt. We quietly went out and bought our own motion discriminators.
Garret and Fisher were late-to-the-game. As you say, it wasn't till 1982-is that Fisher and Garret rolled out their answers to the Whites 6000d. And by then, Whites had the 6000d for about 4 yrs. by then.
In retrospect, the 6000D had a host of downsides (that have since been addressed). But for the era, for certain types hunting (high disc. silver hunting in turfed parks) the 6000d couldn't be touched. Perhaps it could be argued that with reverse discrimination, in moderate soils, that TR disc. could mimic the depth (with less masking), yet the truth was: The 6000D did it 10x faster. Because by their very nature you covered ground faster. Also they handled minerals better in some soils that prior to that had been un-touchable.
In that 4 yrs. or so, it seems that Garrett and Fisher lost a lot of marketing ground. Whites was selling machines like hot-cakes. Even when Garret finally entered the market with the ADSII and ADSIII, it seemed the Whites guys still did better with the original 6000D.
I never much used the 1260x. But recall that it wasn't as deep as the 6000D if I recall.