High frequency for gold and lower frequency for coins...I know over the years all gold nugget machines were real high frequency units but most are interested in gold rings and they are mixed with other metals which may or may not make higher fequencies better for gold jewelry...Any input appreciated...One club member had a unit where he could change from one freq.to the other and always used the low frequency so one wonders as he got as many gold rings as fellow clubmembers. Just a thought for discussion as the paint is not dry on units and they are talking about high frequncy coils...I really don't know but has anyone experimented and could add their thoughts..
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Is it a truism...
- Thread starter Dan-Pa.
- Start date
Dan, metals have a natural resonant frequency. I think we refer to that as the electromagnetic signature of a metal in our hobby. The resonant frequency of gold is higher than for silver. If coins are tested at different frequencies gold and nickle has a higher resonance than copper and silver. Somewhere in all that we end up with the best frequency range for detecting coins and jewelry.
High frequency electromagnetic fields will detect smaller targets than low ones but have less ground penetration. Lower frequencies penetrate the soil deeper but have less sensitivity to smaller targets.
Detectors for tiny gold nuggets are often in the 50khz to 60khz range for this reason and with the idea that not as much depth is needed as searching for deep coins.
With all that in mind if we have a detector operating at 6.5khz and some others at 3.5khz to 20khz than does one do better based on which frequency is used. Not really as I have listened to multiple frequency detectors on gold, nickel, copper and silver and while the sound is different all of them would detect a gold ring, silver coin, etc.about the same. The only serious difference is for tiny pieces of gold then the higher frequency does better. Assume a piece of gold smaller than a bb and some lower frequencies will miss them or only get a faint signal.
Also, gold comes in a log of shapes, sizes and alloys. This also has to be considered. We end up with gold alloys and different sizes and shapes resonating all over the spectrum so find them in just about all areas of acceptance and rejection of a detector. That is were all metal detecting comes in handy.
High frequency electromagnetic fields will detect smaller targets than low ones but have less ground penetration. Lower frequencies penetrate the soil deeper but have less sensitivity to smaller targets.
Detectors for tiny gold nuggets are often in the 50khz to 60khz range for this reason and with the idea that not as much depth is needed as searching for deep coins.
With all that in mind if we have a detector operating at 6.5khz and some others at 3.5khz to 20khz than does one do better based on which frequency is used. Not really as I have listened to multiple frequency detectors on gold, nickel, copper and silver and while the sound is different all of them would detect a gold ring, silver coin, etc.about the same. The only serious difference is for tiny pieces of gold then the higher frequency does better. Assume a piece of gold smaller than a bb and some lower frequencies will miss them or only get a faint signal.
Also, gold comes in a log of shapes, sizes and alloys. This also has to be considered. We end up with gold alloys and different sizes and shapes resonating all over the spectrum so find them in just about all areas of acceptance and rejection of a detector. That is were all metal detecting comes in handy.
Ralph Bryant
New member
n/t
Jackpine Savage
Active member
When it comes to gold jewelry detecting which to me means fresh water wading there are many considerations to take into account, least of which is the operating frequency.
HH Tom
HH Tom
Based on your post if I lived in gold nugget country would buy a good gold nugget unit and get all the nuggets no matter how small..
Whats the reason for the new coil for the 50 model that is close to 20 khz's just to get the large nuggets or am I missing something...as you stated both will get that gold ring...which the majority of hunters are looking for and with a loss of depth and of course at lets not forget the cost of same..
Whats the reason for the new coil for the 50 model that is close to 20 khz's just to get the large nuggets or am I missing something...as you stated both will get that gold ring...which the majority of hunters are looking for and with a loss of depth and of course at lets not forget the cost of same..
That your posts hit the nail on the head and in many cases another coil will basically give you a new machine. Case in point I know one fellow who uses a unit with the stock coil, larger coil and smaller coil and its surprising even in small old yards what one will find that the others will miss...In any case its all up to the operator..Many change machines and others just change coils or a combination of both so whatever works..I really feel one should learn his machine with the stock coil and then move onto the above to become a true detectorist..Many companies have done tests both in labs and in the field and should give you ballparks numbers...
and find something that someone (even ourselves) have missed. Heck, I have been doing that for over 30 years. And it isn't all because of the advancement of technology. We just plain miss them sometimes. Either we sweep too fast or too slow, don't overlap our swaths, or just plain didn't hear the signal. Another reason that we find coins with one coil and not another (on the same detector) might be because of target masking. A smaller footprint on a coil typically allows for a better separation of targets. Simply because the adjoining target is not being detected simultaneously. On the other side of the coin (no pun intended) bigger is not always deeper. But, generally speaking, when comparing coils of the same manufacturer, on the same model of detector and on the same piece of soil, a larger diameter coil will allow greater depth of detection. Again, simply because of the diameter of the magnetic field, produced by the windings, and being induced into the earth. Randy
Beachcomber
New member
Basically the rule of thumb is that the smaller the gold that you are looking for the higher frequency machine you need to find it. For larger men's gold rings the 6.5khz machines do very well and will have more overall depth. The detectors that run in the 12-20khz range will find gold down to grain size and the 30-70khz machines can find gold flakes and gold that you need a magnifying glss to see. An example is a thin gold chain that I use for testing machines ability to see small gold. Since a detector only sees the individual links of a chain it's very hard for most detectors to find the thinner gold chains. So far I have not found a machine that runs below 10khz that can even see this chain. The Tesoro Lobo ST sees it easily but can only detect it at about 2.5-3". The Fisher Gold Bug 2 operating at 72khz can see this same chain at 6". But if we reverse things and use a large man's gold ring the results are totally different. Now the 6.5khz detector is the clear winner by several inches over the Gold Bug 2 but only marginally better than the Lobo ST. Another factor is that small gold being lighter usually doesn't sink as deep as a larger piece of gold.
Since you said the person from your club has a 3 frequency but only uses one I think you are probably talking about one of the Minelab's such as the Eureka Gold or one of it's older predecessors the XT17000 or XT18000. I would think that with that detector if the person hunted the same area 3 times once using each frequency he would find more gold each time he went over the area. I always wanted to try one fo the Minelab 3 grequency gold machines but never did because they don't have waterproof coils If they did I would have bought one long ago!!!! Instead I settled for an American Made Tesoro Lobo ST running at 19khz as a good overall compromise for my gold hunting because like ALL American made detectors it's coils are waterproof and always have been!!! Still if Minelab ever came out with a 3 frequency gold detector with waterproof coils I would buy it in a heartbeat!!!!
HH
Beachcomber
Since you said the person from your club has a 3 frequency but only uses one I think you are probably talking about one of the Minelab's such as the Eureka Gold or one of it's older predecessors the XT17000 or XT18000. I would think that with that detector if the person hunted the same area 3 times once using each frequency he would find more gold each time he went over the area. I always wanted to try one fo the Minelab 3 grequency gold machines but never did because they don't have waterproof coils If they did I would have bought one long ago!!!! Instead I settled for an American Made Tesoro Lobo ST running at 19khz as a good overall compromise for my gold hunting because like ALL American made detectors it's coils are waterproof and always have been!!! Still if Minelab ever came out with a 3 frequency gold detector with waterproof coils I would buy it in a heartbeat!!!!
HH
Beachcomber