Coil question for the 705 gold

[everyday]

Hi All,
After months, days, and hours searching forums I've decided on the 705 gold as my first detector. I need advice on what coil would be best for my type of detecting. About 60% of the time I will be detecting on Ohio farm ground, and parks. The other 40% will be in the Quartzsite, AZ area detecting for gold. What do you all recommend?

Thanks
Everyday

 

[Old Longhair]

If you're starting with the Gold Pack, then you'll already have your basic prospecting coil, so for the farm ground I'd recommend a larger MF DD. The Coiltek 15" would be great for the farm, but would risk missing stuff due to masking at places like parks where the trash density is up. So the 10.5" MF DD would likely be the most practical. Later, if you decide that it might be an advantage to go deeper, you can invest in a 15", and you'll have a better idea by then of which frequency coil will do what you want.

 

[everyday]

Thanks Old Longhair
Sounds like good advice
I really need to find a beginners book, something that starts with " this is a metal detector" then proceeds on. Although I'm lost in most post I'm slowly getting there.
Again thanks
Everyday

 

[Old Longhair]

If you haven't already, you should sign up on the Minelab website, Then go to the MEMBERS area and download Randy Horton's free E-book "Understanding Your Xterra". It's an easy read and packs more useful information into an understandable format than you will find anywhere else.

Beyond that, I would highly recommend going through the FAQ-FAQ thread at the top of this sub-forum page. There are many links to videos and articles to assist you in learning your fantastic new machine.

 

[everyday]

Many thanks again.
Will do both
Everyday

 

[7centsworth]

Welcome to the forum.

 

[Mark in S.E. IA]

hi Everyday, What I would do first is wait until you get your MDer and use it some in different areas to see what kinds of ground balance numbers you get. that might help you in decideing on which coil to buy. I have a friend in Ohio. Goes4ever and several years ago I talked him in to buying the 10.5 MF DD coil and it just did not work for him too good because of the mild ground in his area. Here in IA I have a lot of hot ground so it works great for me so I would say to hold off on buying another coil until you know what type of ground you have in your area and then come back to the forum an tell us what kind of GB numbers your seeing in your area. then we can help you out a lil better in choosing a new coil.

 

[Old Longhair]

hi Everyday, What I would do first is wait until you get your MDer and use it some in different areas to see what kinds of ground balance numbers you get. that might help you in decideing on which coil to buy. I have a friend in Ohio. Goes4ever and several years ago I talked him in to buying the 10.5 MF DD coil and it just did not work for him too good because of the mild ground in his area. Here in IA I have a lot of hot ground so it works great for me so I would say to hold off on buying another coil until you know what type of ground you have in your area and then come back to the forum an tell us what kind of GB numbers your seeing in your area. then we can help you out a lil better in choosing a new coil.

Only problem with that Mark, is that he's getting a Gold Pack, so his GB numbers will be with a HF coil and not necessarily a good basis for making a determination.

Someday I'll have to get a hold of G4E to find out the speciffics of his beef with the 10.5 MF. I've never heard of trouble due to mild soil before. I could understand that he may have felt that the depth advantage of the concentric was better in his mild ground, but I can't see how the DD wouldn't work.

 

[Mark in S.E. IA]

Longhair, are the GB numbers that much of a difference between the MF and the HF coils where you can not get a idea if the ground is hot or mild? I do not have the HF coil and it's been about 6 years since I have used the Conc. coil to know if their is a big difference in GB numbers between the coils.

 

[Billium]

Thanks Old Longhair
Sounds like good advice
I really need to find a beginners book, something that starts with " this is a metal detector" then proceeds on. Although I'm lost in most post I'm slowly getting there.
Again thanks
Everyday

Everyday,
Jump on Minelab's web site, go to Knowledge Base and down load Randy's book "understanding your X-Terra". Good book and very helpful to me when I first got mine. I got mine from a dealer who actually trains his customers on how to use their machined but the book helped even more.

 

[Old Longhair]

Longhair, are the GB numbers that much of a difference between the MF and the HF coils where you can not get a idea if the ground is hot or mild? I do not have the HF coil and it's been about 6 years since I have used the Conc. coil to know if their is a big difference in GB numbers between the coils.

Not necessarily that much different, and that can in itself be deceiving.
Part of the difference would be because of te difference in search patterns, and the frequency's response to the minerals is another. That response varies due to the earth's lack of consistant levels of both conductive and magnetic minerals. I've corrolated just enough data to conclude that the HF coils will have higher GB numbers where the levels of conductive minerals is high and magnetic minerals is low compared to lower frequencies. And the inverse is also true.

So, he could show reasonably high numbers with his HF coil, and have a LFcoil not work worth spit. He could also have low numbers with the HF and still not get good results with the LF, or any other number of combinations that you can come up with. Measuring both magnetic and conductive minerals separately and comparing to existing data is about the only way w/o having a stock 7.5kHz 9" to use for a baseline.