Frequency

pastorals · May 10, 2011

Please pardon this dummy question, but different detectors operate at different frequencies. Is one particular freq. better than another? Does a higher freq. have an advantage over a lower freq. for a particular type of detecting? Or vice-versa? In other words, can someone 'splain these freq. for me? Thanks

Alan

rockhound · May 10, 2011

That is not a stupid question at all. Many people are confused when it comes to detector frquencies. Most detectors are VLF(very low frequency),since about the early 1980's. That being said,detector manufacturers have their own particular frequency used in their products.They can vary from about 5KHz to 25KHZ. Most all purposed detectors stay closer to the lower 5-12.5KHZ,as they are more sensitive to silver and copper,which is what most people find. Gold detectors, on the other hand,have a higher frequency from 12.5-50KHZ,which is more senstive to lower conductivity metals(gold,nickel,brass),where most people are searching for gold nuggets and need to find tiny bits of gold that most all purpose detectors would pass over. Also most gold detectorist use no discrimination,which could mask small gold.Most relic detectors are in this range also, to find brass,especially civil war relics(buttons,belt buckels).The multi frequency detectors scan the ground and try to match up a frequency to the greound mineralization. These work best on the beach, or where highly mineralized soil exists. Also there are pulse detectors. Mostly used for the beach or gold prospecting,where highly mineralized soil can wreak havoc on most VLF detectors. It all depends on what type of detecting and where you will detect most when determining which will work best for you. Most poeple have several detectors to fit most situations they might encounter.I hope this gives you some insight into frequency variations. Good Luck. rockhound

pastorals · May 10, 2011

Yes, that does help a lot, thank you... but it raises another question. You say the higher freqs. are good for relic hunting while the lower freqs. are good for copper and silver coins. My question now is, how do some manufacturers claim their detector is both a relic hunter and a coin shooter??

Alan

ivan salis · May 10, 2011

relics -are mostly lead , iron or copper items * --- gold is a lower end of the scale item * similar to aluminum thus higher freq's pick up tiny bit of "raw natural GOLD"

some VLF models are single freq that will pick all the items up but are not really the "best" freq for any one set of items

pastorals · May 10, 2011

Ahhh...I get it...find the common denominator. Makes sense.

Thanks for the lesson

Alan

Terry Soloman · May 10, 2011

pastorals said:
Please pardon this dummy question, but different detectors operate at different frequencies. Is one particular freq. better than another? Does a higher freq. have an advantage over a lower freq. for a particular type of detecting? Or vice-versa? In other words, can someone 'splain these freq. for me? Thanks

Alan

Can't say it better than Rockhound, but will just add: Look for the best detector that you can AFFORD, and will do the best job finding what YOU want to find. Gold Nuggets? Minelab GPX5000 Pulse Induction - $5,000.00 or, Tesoro Lobo SuperTRAQ (17.8kHz) Very Low Frequency - $800.00 There is a machine for every purpose - and budget. Good Luck Alan!

glabelle · May 10, 2011

What was just said here was repeated urban legend. Regurgitated replies that are not accurate and not scientific.

Lower frequencies are not more sensitive to coins, and higher frequencies are not more sensitive to gold and lower conductors. Higher frequencies are in fact more sensitive to all metal! Lower frequencies are able to discriminate between mineralized ground and higher conductors. Higher frequencies, because they are more sensitive to all metals, are able to pick up small conductors, like small gold nuggets better. That is the fact.

If you want to find deep silver coins, you would want to use a low frequency detector (up to a few KHz), in average mineralized ground, because it is able to differentiate better (because of the way the electronics work) between the ground matrix and the high conductive coin. In air, or ground that has very little to no mineralization (depends upon what area of the country you are in) a high frequency detector would do better for all types of hunting. That is why the Minelabs have gained the reputation of the "deep silver" machine, because they operate as low as 1.5KHz. Machines made specifically for gold hunting are in the 20-50KHz range for sensitivity to small targets/metal (the average nugget).

George
Aloha, Oregon

U.K. Brian · May 11, 2011

Glabelle sums it up rather well but then you have to take account of size as well. Pure gold reacts as a high conductor at a quarter oz. or above and silver coins if small become low conductors.

Most DFX books say straight out that the lower frequency (2.98 kHz) is what should be used for silver coins. Try that in Europe and you find your not doing at all well for hammered silver and its far better to use the detectors higher (14.91 kHz) frequency. A deeper silver U.S. coin in effect shrinks as far as the detectors electronics are concerned so may be detected more easily with a higher frequency. Mineralisation has its effect to be taken into account and should be the decider as to frequency choice as you can tell how bad the ground is but you have no idea whats under it.

Really the only rule is that there's no rules.

ivan salis · May 11, 2011

3 and 15 are highly popular freq's -- one for its ---for depth / the other for detecting small items

pastorals · May 11, 2011

Well, Ivan I guess I'm right on target...I'm planning on buying a Tesoro Vaquero - 14 kHz

Alan

ivan salis · May 11, 2011

if your looking for "small raw gold" yes -- or small gold items in general --yep

of course it will find bigger gold as well.

Terry Soloman · May 11, 2011

glabelle said:
What was just said here was repeated urban legend. Regurgitated replies that are not accurate and not scientific...

...Machines made specifically for gold hunting are in the 20-50KHz range for sensitivity to small targets/metal (the average nugget).

George
Aloha, Oregon

Hi George! No need to slam folks and call them names. If you don't agree, just say "I don't agree." For instance, I don't agree that "machines made specifically for hunting gold are in the 20-50kHz range.." The VLF machines most commonly used for gold prospecting are the Fisher Gold Bug II (18kHz), the Tesoro Lobo SuperTRAQ (17.8kHz), and the Whites GMT (17.8kHz). We use them to look for sub-gram gold at shallow depths of 2" - 9". We all know you mean well, but slamming people when they are just trying to help? Let's go find some Treasure! - Terry

rockhound · May 11, 2011

Each detector manufacturer has their own target frequency that they use in their detectors. Most also build specialty machines for gold,relics and general purpose. Although many manufacturers have frquencies close to one another, they will differ somewhat,mostly according to the electronics used and how the coils are wound. Their engineers spend many hours in R&D trying to find the one frquency or design to give them an edge over their competition. No one frequency is better than another except in certain ground conditions. There are just too many valuables to consider. More than frequency are a whole other world of things to consider when purchasing a detector. There are many variations,turn on and go,TID,manual ground balance,notch discrimination,volume control,frequency adjustment,silent search,tone adjust,coil configuration,plus the weight of the detector are all contributing factors.All detectors will find treasure,but specialty detectors will work better using them for their designed purpose.Good Luck. rockhound

U.K. Brian · May 12, 2011

There was a post by one of the top Polish designers last year explaining why he had developed some detectors that would appear to be operating at the wrong frequencies for the task they were designed for and come to that it wasn't that long ago that the Dave Johnson and John Gardiner interview was on most U.S. forums. This stated that "frequency is no longer critical".

I didn't think George was rude he just stated the facts....times (and detector design) change.