HF vs LF on depth of high conductive target question.

[bigtim1973]

Ok so reading in my Deus manual the new style HF coils do not offer the remote boost mode as found on the 4khz X35 coil option as it says it does not need it and they will not be updating the HF coils to do so either as it states the battery life with boost mode on the HF coil would reduce it to about 6 hours of detecting time since it uses so much power.

So with this being said...everything seems to not stand true for what I have been told and read about all my detecting years that lower frequencies are best for deep coins and higher frequencies for gold and brass.

After using higher frequencies the past several years.....to me it seems that since higher frequencies see lower conductive smaller targets better in trashy sites........ wouldn't higher frequencies see high conductive large targets and coins better at depth as well?

It seems that way to me from my own experiences....how about some of you all??

Also read in the manual that the 50 khz frequency uses the least amount of power from the battery in the coil. Very interesting to me. I have not searched much on 50khz but use 31khz for the most part. May try that out.

 

[Jim in Idaho]

The problem is high freq's don't penetrate against the ground mineralization very well. The reason they're used for gold is because tiny pieces of gold give almost no response to lower freq's. And most gold is pretty small. Another problem is how we talk about all this. We call some targets "High conductors", and others "Low conductors". But what we're actually meaning is how well they create and retain an electrical current in the presence of a moving magnetic field. Gold is actually a much better conductor than iron, but ferrous metals respond to the transmit coil's magnetic field much more strongly than some non-ferrous metals, including gold. Take a look at a chart of metals on "magnetic reluctance".
Jim

 

[bigtim1973]

Well I see that in high mineral soil conditions but here in my mild soil the high frequency setting do very well on deep targets.

It really does not seem like it should but it works.

I have talked with a few more on other forums who are having great luck at pulling old silver up with the elliptical coil and 72khz and getting 12 inches.

I think that's pretty impressive.

However in high mineralized ground I see where the limitations can fall into place.

 

[Jim in Idaho]

ALL metals respond better to hi-freq's. The reason the makers don't use it for all their detectors is the ground mineralization problem.
Jim

 

[LTimedigger]

This is my steadfast rule. If only coin digging use the X35 at 8kfz and switch to 4 to check for trash. The 4 with boost is terribly noisy in trash so never run it. Run on 28 with the elip if wanting to look for coins and gold. Its really deep on the high conductors but begins to lose depth above 28 on the high conductors. Use 28 and 54 for relics. Ive only been able to pick up tiny gold chain with the 78 but it will also pick up lots of tiny aluminum. Best.

 

[bigtim1973]

So from your experience your saying you see a loss of depth past 28 khz for high conductors then right and stick to the higher frequencies while relic hunting??


Thanks for sharing your input. What part of the USA are you in and what is your soils mineralization like??

 

[kaolinwasher]

I have the X35 on the ORX and i have a 8" dime at the 27khz i cant detect it , but at 8 and 12 Khz it comes thrue nicly. I am glad I got the x35 coil I was tryng to get the HF 9" but i just could not get one so i settled for the 9 X35 and am glad i did its got a wide range, I have found that even 12 Khz is good on silver AND Gold

 

[jmaclen]

Very interesting topic BigTim1973.
Like Jim from Idaho, I am a gold prospector and love to use my ORX on 31kHz or higher for really small gold. I also use my ORX for coin and jewelry sometimes. In my moderate to high mineralized dirt I have to use higher frequencies. I only own one single frequency detector which runs at 19 kHz. All of my other detectors have selectable frequencies or are multi frequency just for the high mineralization. The lower frequency "normal detectors" running below 14 kHz get no depth here at all since the lower frequency wavelengths are just too big to penetrate the mineralization fog. Higher frequencies may not punch as deep but they will penetrate the mineralized ground easier than lower frequencies. It is a trade off for sure.

So, this is just my opinion OK? I believe that running higher frequencies no matter what soil conditions are, can occasionally hit deeper targets that are showing a small profile for whatever reason. Maybe they are deep coin sized or less sized objects. Maybe they are tilted or on edge, partially masked or are just not giving a "big" profile that a lower frequency detector would hit easily. This is sort of like the tiny sub gram gold I often find at 3" or less which a detector running below 19 kHz would completely miss.

Jeff

 

[LTimedigger]

So from your experience your saying you see a loss of depth past 28 khz for high conductors then right and stick to the higher frequencies while relic hunting??


Thanks for sharing your input. What part of the USA are you in and what is your soils mineralization like??

Exactly. Keep in mind the HFs "bunch" your numbers more but not at issue if your doing relics. Calabash does a nice utube using the 54 for deep relics on "pitch". Way too noisy for trashy areas but great for cleaner sites. Found a rare Whitworth CSA bullet with this program. Live in LA most areas real low mineralization-advantage. Most good stuff real deep-disadvantage. Best.

 

[bigtim1973]

Very interesting topic BigTim1973.
Like Jim from Idaho, I am a gold prospector and love to use my ORX on 31kHz or higher for really small gold. I also use my ORX for coin and jewelry sometimes. In my moderate to high mineralized dirt I have to use higher frequencies. I only own one single frequency detector which runs at 19 kHz. All of my other detectors have selectable frequencies or are multi frequency just for the high mineralization. The lower frequency "normal detectors" running below 14 kHz get no depth here at all since the lower frequency wavelengths are just too big to penetrate the mineralization fog. Higher frequencies may not punch as deep but they will penetrate the mineralized ground easier than lower frequencies. It is a trade off for sure.

So, this is just my opinion OK? I believe that running higher frequencies no matter what soil conditions are, can occasionally hit deeper targets that are showing a small profile for whatever reason. Maybe they are deep coin sized or less sized objects. Maybe they are tilted or on edge, partially masked or are just not giving a "big" profile that a lower frequency detector would hit easily. This is sort of like the tiny sub gram gold I often find at 3" or less which a detector running below 19 kHz would completely miss.

Jeff

I see what you are saying. If at depth the high conductive target could be a coin on edge and the higher freq can reach out and touch it better and make a better tone signal more so than a lower frequency would do.

 

[jmaclen]

The Deus, ORX, Anfibio, Kruzer, VX3, V3i, and Equinox all make it possible to totally grid a search area since they have selectable single frequencies and/or multi frequencies. The vast majority of detectable targets are going to be detected by hunting from different directions and by using different frequencies even if they are small, deep or poorly oriented.