Roscoe,
Yes, I did get the detector to hiccup over the rocks. What I also found was what I mentioned in an earlier post and that was the GB over such radical ground (as a box of the rocks) isn't perfect or linear, meaning it might GB at 1" but have a different GB setting at 2" or less than 1". So, the hiccup happens as a result of the GB change.
This happens with ML's also and I bet they can't run a plain mono without a lot of mods or serious detuning. I used to own a SD2100 and a SD2200 and both of them were far worse and touchier when it came to GB'ing. I am guessing they use DD coils or a form of cancel mode.
Now, I haven't given up on finding a simple solution to eliminating the hiccup. I believe it can be done.
I did try a home made DD coil and it GB's at the same GB number as my mono's even over the rocks, which makes me wonder why others are having a problem. I think I know the answer but I need to find my old DD ML coil to see.
One more thing, the gain pot on the SPP and SL is a 50K so the gain of the last main amp ranges from a gain of 1 to a gain of 50. This is a radical range and is really too wide. As you will find out, a gain of 1 or other very low number doesn't work well on small gold, but the SPP or SL in disguise was made more as a universal detector and as such could use a very low gain with looking for larger near surface objects such as ring just lost.
What even White's found was after a certain gain, about the only thing gained is more noise. Any depth increase is minimal like Dazza found. The extra gain was left because the noise reduction circuit minimized the negative effects. Unfortunately, we don't have ground over here that even comes close to the conditions you have so the excessive gain problem was never noticed or even able to be created. I did it with some special rocks sent to me from OZ. I was told those rocks were like metallic objects but had no metal and made it impossible to use a VLF. So, many years ago, I paid a guy to send me some. Obviously, I asked him to wash and then spray the rocks with strong weed and bug killer before they were sent.
Right now, I am waiting to see if you get a response from White's, but in the mean time, I will try a couple of ideas I have.
If you think what you have is bad, well you would absolutely hate my original SL prototype. In noisy areas it is radical and extremely noisy. The gain was far greater than what is on the final product. Because it was so noisy, I ran some tests and found a certain point were about the only thing that happened was a noise increase, which is what Dazza found. The only difference is I can only get my gain to about 4 or 5 on the prototype before the noise is a major problem. The SPP I have is modified just like your detectors and is not like my original SL prototype so it runs normal over here even at max gain. So, my SPP works fine here with no hiccup you are experiencing.
Anyway, getting back to the SPP, I am confident a simple solution can be found and I will continue to work on it.
Reg
