My first impression from doing limited testing on the new HF 81 khz coil are positive to a point. I have not completed all the testing that needs to be done. This trip I hunted for a certain type of gold in tailing piles so not all types of conditions for nugget hunting were met on this hunt. When hunting tailings I encounter iron, trash of all sorts and non ferrous unwanted targets ( Aluminum beer and pop cans). People just won't take their trash with them. PICK IT UP PEOPLE!!!
I have been working on creating a program with the 9″ standard coil but was not happy with the results. It worked out great getting rid of unwanted targets both trash and unwanted non ferrous targets. The problem I encountered was it would not see some small gold. So when XP Deus announced the new HF coils I was excited at the possibilities. I was apprehensive though since I have been around nugget hunting with different machines and technology everything needs testing to prove it in your areas.
With the 80.8 HF being the highest frequency that I have used over a piece of gold I was hoping for the good things to happen. I have used the Fisher Gold Bug 2 for years and it's 71 khz is a killer on gold and especially small gold.
What I was looking for with the XP Deus was being able to discriminate out unwanted targets and still finding small gold in specimen pieces as well as big gold of course. From my experience with the Deus I knew it really likes hot rocks, it will sound off on them like a pop can. In the area I was hunting there are 3 different frequency"s of hot rocks. With the lower frequency coil I was able to notch or discriminate them. With the HF coil that was not happening.
I had to come up with a new plan. I tried to ground balancing over them but with different kinds that was a no go. The answer go to – tracking mode in the ground balance. It worked perfectly, the hot rocks were gone immediately.
Now I know that using tracking can cause other issues. For instance you can track out a good target with some machines. You also will lose depth. Manual ground balance is always better for getting the most out of your machine. I had to use what worked for my needs in this area. Tracking was that choice. I now had to test out how much sensitivity and depth I was losing. I placed different types and pieces of gold on the area and ON the hot rocks to see if this would work for me.
Here is an example of the gold I tested.
I did lose depth but it was not enough to bother me. When hunting for this type of gold you are looking for larger pieces but will be happy with the little ones as well. Depth is not the biggest concern because digging in rock piles at depth is not productive. There are way too many big chunks of iron found after digging forever with all the rocks falling in your hole. For me in this type of gold hunting is 6 to 8 inches of depth and cover ground is the choice.
I did try the gold only program but it was not the way for me. Now out in clean ground it might be the way to go. When I get a chance to give that a go I will but that was not my goal for this trip.
I used a modified 2 tone coin program to get the XP to perform with the HF coil. I was not able to discriminate out all non ferrous targets like I hoped. The reason being the HF coil reads gold from just over 30 to high 90's on the ID meter. Both type and size of gold makes a difference. In order to dig only the better targets and to identify big iron I also set up my coin program on 14 khz in the next slot to check some of the targets I encountered. It makes things more efficient and wastes less time. The more targets you get over and check the better your odds of hitting the GOLD.
Ron, would love to know the specifics of your program settings. I was able to find two small (0.1 gram) targets last year just using Gary's Hot program at about 79hz. Had zero issues with hot rocks but may have been missing targets due to programs specifics.