Xterra 705 general question

[DigginDoc]

I have read Randy's information on which coil is best as well as other stuff on it. Thanks Randy I have downloaded your book also. My question is,
What do you posters think is the best DD coil or otherwise for general hunting in parks, schools, and fields? Keeping in mind coverage of the ground and all assorted targets. I have yet to find any gold with mine and that has caused me to go back to one of my other units. I try and dig every good signal on the plus side. I have found good silvers etc.
Basically what is your favorite?
Thanks
Doc

 

[mapper65]

I'd have to say for open field areas you can't go wrong with either of the 10.5" DD's. I know that's a vague statement. I have both and I've done really well with both coils although I have to say that the MF is not as strong in the nickel department. If you are going to buy just one of the two coils and you ever plan on beach hunting then I would go with the HF version. It's a little better with the type of mineralization that you will have on a salt water beach.

I've always favored the HF coil but I think I overlooked something that makes these two coils now play on pretty even ground. The MF coil is not a quick to react as compared to the HF coil. I think my original dissatisfaction with the MF coil was that I was expecting it to react as quickly as the HF coil. Once I slowed my swing down while using the MF coil it really started to shine just as much as the HF coil. I'm almost to the point that I don't care which one I grab. I think a person's detecting abilities as far as knowing what to listen for when using either of these two coils is more important than the coil itself.

I'll also add that when using the 6" coils, the HF does a little better job and gives you a little better depth. I recently found my second oldest coil with the 6" MF coil but it is still not my favorite of the two smaller coils.

 

[DigginDoc]

I'd have to say for open field areas you can't go wrong with either of the 10.5" DD's. I know that's a vague statement. I have both and I've done really well with both coils although I have to say that the MF is not as strong in the nickel department. If you are going to buy just one of the two coils and you ever plan on beach hunting then I would go with the HF version. It's a little better with the type of mineralization that you will have on a salt water beach.

I've always favored the HF coil but I think I overlooked something that makes these two coils now play on pretty even ground. The MF coil is not a quick to react as compared to the HF coil. I think my original dissatisfaction with the MF coil was that I was expecting it to react as quickly as the HF coil. Once I slowed my swing down while using the MF coil it really started to shine just as much as the HF coil. I'm almost to the point that I don't care which one I grab. I think a person's detecting abilities as far as knowing what to listen for when using either of these two coils is more important than the coil itself.

I'll also add that when using the 6" coils, the HF does a little better job and gives you a little better depth. I recently found my second oldest coil with the 6" MF coil but it is still not my favorite of the two smaller coils.

Thanks very much Mapper. I was considering the 10.5 HF as the better choice at this time. Even though there re fresh water beaches here, I go to the coast quite a bit to salt water areas and want to be prepared. Your information was very helpful.
Cheers and HH
Doc

 

[chuckciao]

Ditto with everything Mapper65 said about the 10.5 DD. I have the 7.5 Mhz mainly for increased depth. In fact, I have had it on my machine for the past 6 months. Initially, I thought it was going to be too heavy but that changed the more I used it.. My second would be the 6 DD HF if you are hunting extremely trashy areas.
HH
Chuck

 

[Mtnmn]

For parks, schools and fields you won't go wrong with using either of the 10.5" DD coils and although the 10.5" HF coil may hit slightly harder on nickels, the 10.5" DD MF coil is no slouch in that department either as over 12.5% of my total coin finds this year have been nickels while using the 10.5" DD MF coil on the XT-70. Like mentioned previously that little 6" DD HF coil has good depth for its size and it is surprising on how small of gold it will hit on. A "general" rule of thumb would be to use a DD MF coil if more interested in silver than gold and a DD HF coil if more interested in gold than silver and the 9" LF coil if concentrating solely on finding silver. Also the smaller the DD HF coil the smaller the gold it will hit on, but at a loss of depth on bigger gold as compared to the larger DD HF coils.

 

[rseasy1]

It's my understanding that the DD coils will perform better in higher minerlized ground I usualy ground balance in the low 20"s to upper teens in my area
so I used the 10.5" 7.5KHZ DD coil,If this wrong please correct me! I can't tell any better results between the DD and stock concentric but I guess the machine can so thats
what matters to me.The 705 runs smooth and quite and I get good depth and get alot of good finds.
HH.

 

[lerafe]

It's my understanding that the DD coils will perform better in higher minerlized ground I usualy ground balance in the low 20"s to upper teens in my area
so I used the 10.5" 7.5KHZ DD coil,If this wrong please correct me! I can't tell any better results between the DD and stock concentric but I guess the machine can so thats
what matters to me.The 705 runs smooth and quite and I get good depth and get alot of good finds.
HH.

Good question, I am interested in the answer to thet also

 

[Old Longhair]

With a same size DD and CC, the DD will tend to do better in highly mineralized soil than the CC because it is looking at a narrower slice of ground, and is thusly effected by ground minerals less.

Beyond that, the 7.5 will have more honest TID over the entire range, and the HF will tend to be less accurate on high conductors due to the difference in bin widths.

 

[Digger]

The number on the display when you ground balance is actually a numeric representation of the phase angle of the ground. That is why I refer to it as the ground phase number, not the ground balance number. Ground phase does not tell us how strong the mineralization is. But it does tell us if it is more magnetic in one area than another. (smaller ground phase numbers are indicative of more magnetic soil conditions and larger ground phase number are typical of less magnetic soil.) Regardless, when you properly set the ground balance on the 705, you are electronically adjusting what the detector interprets as the phase angle of the ground. The parameters of the ground phase adjustments on the 705 are: 0 = -1 degree .................. 90 = +9 degrees. So in your example, when you are able to ground balance your 705 with a ground phase reading on or around 20, your detector has determined that the ground at that specific location requires a "phase shift"" of approximately +1 degree, to allow your detector to "compensate" for the phase angle of that soil. If you don't properly ground balance your detector, TID numbers become skewed and you can actually end up getting an audio response from the soil itself.

In my eBook, "Understanding your X-TERRA", I talk about my "theory" on when it is best to use a DD coil, compared to a concentric coil. I believe that if you are able to properly set your ground balance with a ground phase reading of 28 or larger, when using the 9-inch concentric coil at 7.5 kHz, the soil conditions (low to moderate magnetic mineralization) allow for concentric coils to perform quite well. However, if when properly ground balancing your X-70 or 705 you get a ground phase number that is smaller than 28, your soil conditions indicate a higher level of magnetic mineralization and would be better served by using a DD coil. That does not mean that you can't use a DD coil for areas that are moderately mineralized. Nor does it mean that you can't use a concentric coil in areas with higher levels of mineralization. It simply means that, in my opinion, to get the optimum performance out of your X-TERRA, you need to equip it with a coil design that allows the electronics to best "compensate" for the mineralization and provide the most effective phase angle adjustment. And the "magic" ground phase number of 28 is what I came up with. JMHO HH Randy

 

[lerafe]

... when you properly set the ground balance on the 705,........ If you don't properly ground balance your detector,....

if when properly ground balancing your X-70 or 705 ........HH Randy

Great info as always Digger. This may be a bit simplistic of a question. I may be splitting hairs, our over complicating things, but in the above quotes, the part that concerns me is the "properly ground balance".
Question... I think GBing is fairly simple, but worry when reading about "properly ground balancing" that I may not be GBing correctly. Is there a way to not properly ground balance? Is there a way to tell if not?
Thanks,
Lee

 

[Digger]

If you follow the procedure outlined in the manual, you'll be OK. Just make sure you don't have the coil over any metallic objects when you perform the GB. Bobbing it from 1 - 8 inches is good. Just don't let the coil touch the ground while bobbing up and down. Using the Auto GB procedure will provide more accurate results than relying on our ears in the manual GB method. Another method that works well is to simply put the 705 in the Tracking mode, make a few sweeps, and then shut off the Tracking when you are sure the coil is NOT over a metallic object. JMHO HH Randy

 

[baggins]

Great info, thanks!