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Single Frequency
- Thread starter prester
- Start date
Under those conditions they all are deep.
Best Frequency to Use is determined not only by metal content, but also size and thickness. For thicker coins with high silver content there is no question that 2.5 kHz will hit harder than 22.5 kHz. For US nickels 22.5 kHz will hit hardest. 22.5 kHz may also work best on small thin coins, even those with high silver content, due to skin effect. High frequency may also work best on low silver content coinage. 7.5 kHz is typically better on copper coins. Test the detector for the items you want to find. If all you want is US silver, then you should use 2.5 kHz. If all you want are thin gold rings or small nuggets, then select 22.5 kHz. If you want the best depth on a wide range of targets, use 3 frequencies.
Best Frequency to Use is determined not only by metal content, but also size and thickness. For thicker coins with high silver content there is no question that 2.5 kHz will hit harder than 22.5 kHz. For US nickels 22.5 kHz will hit hardest. 22.5 kHz may also work best on small thin coins, even those with high silver content, due to skin effect. High frequency may also work best on low silver content coinage. 7.5 kHz is typically better on copper coins. Test the detector for the items you want to find. If all you want is US silver, then you should use 2.5 kHz. If all you want are thin gold rings or small nuggets, then select 22.5 kHz. If you want the best depth on a wide range of targets, use 3 frequencies.
Neil in West Jersey
New member
One thing I have noticed is that many times Best Data - Multi Freq. allows me to raise up the gains and sensitivity a bit higher, which negates any advantage of single frequency use.
Rob, your assessment about frequency and types of targets needs qualification. The frequency you use depends upon the ground you are hunting in! This is one of the least understood technical aspects of detecting. Firstly, 22.5KHz is more sensitive to ALL metals, therefore its reputation as being better for low conductors and small nuggets, etc. Secondly, the low frequency (2.5KHz) can be more sensitive, in practice, to high conductor coins like silver dollars - only if the ground you are hunting in reads VDIs in the high -90s. This is due to the wrap around effect and the fact that your ground balance when set to a high negative value, renders the detector less sensitive to high conductor larger coins. I've discussed this at length with Jeff Foster and he has explained this in his DFX book amongst other places.
In fact, I was told by another prominant detectorist that he had tested some detectors once from a well known manufacturer that would not detect a quarter! The reason was that they had improperly set the internal fixed ground balance.
George
Aloha
Oregon
In fact, I was told by another prominant detectorist that he had tested some detectors once from a well known manufacturer that would not detect a quarter! The reason was that they had improperly set the internal fixed ground balance.
George
Aloha
Oregon
Larry (IL)
Well-known member
Rowan's explanation supports what Rob said 100% and counters your assumption the 22.5 is more sensitive for ALL metals. If 22.5 was more sensitive to ALL metals, ALL detectors would be using 22.5.
PokerShark
Member
WOW! That presentation is VERY informative and helps to understand why the V employs the 3 frequencies that it does. Not to mention it further validates my reasoning for going with the V over an E-Trac in the first place. Not that the E is a bad machine because it is not. It is just a different bite of the apple for a different need. I enjoy more information and the V certainly supplies it.
Thank you gentlemen for the great info.
The Shark
Thank you gentlemen for the great info.
The Shark
Glabelle,
I see you are asking Carl to clarify. Honest what I posted is what he posted in an earlier post. He is Carl's post.
http://www.findmall.com/read.php?66,1078329,1079961#msg-1079961
Here's Jeff's post, http://www.findmall.com/read.php?66,1153936,1153936#msg-1153936
He's not saying what we said is not true. He just explains why.
I see you are asking Carl to clarify. Honest what I posted is what he posted in an earlier post. He is Carl's post.
http://www.findmall.com/read.php?66,1078329,1079961#msg-1079961
Here's Jeff's post, http://www.findmall.com/read.php?66,1153936,1153936#msg-1153936
He's not saying what we said is not true. He just explains why.
I was not going to respond further, but since you want to chase me around the Internet... ;-)
I'm attempting to get clarification from Carl on the Whites forum. I'm a retired electronics engineer, and understand fairly well how metal detectors work, circuitwise.
I know what Carl wrote, but his explanation, was not technical and misleading from an electronics perspective. What does "hit harder" mean, and why? Also, if you'd watched the video I referred to, the detail was there, but was not obvious, While Mark made a sweeping statement about low frequency was better for high conductors and vise-versa, he did not clarify it. The detail was in the VDI wheel and how frequency relates to it - and the discrimination circuitry (which really wasn't mentioned).
Note Mark said 1) The length of the arrows represent intensity. 2) the higher the frequency, the more target arrows point to the right, towards the +95 axis (all metals higher intensity). However, this crams all the high VDI numbers together, towards the +95 axis, which is real close to the -95 axis coming up from the bottom. If your ground balance is near -95 (near +95 on the wheel), then you lose sensitivity to the +95 signals due to the "wrap around" of the circuitry. Another way of putting it - your discrimination has only a couple of VDI numbers to work with. An analogy would be setting discrimination to +24, when nickels are +26 - you would then lose sensitivity to nickels due to the lesser ability of the circuitry to differentiate between the two. That is why you normally set your discrimination to JUST reject nails not further. This is the real reason silver coins are "hit harder" with the low frequencies - due to the discrimination circuitry, not the frequency itself. Does this make sense?
George
I'm attempting to get clarification from Carl on the Whites forum. I'm a retired electronics engineer, and understand fairly well how metal detectors work, circuitwise.
I know what Carl wrote, but his explanation, was not technical and misleading from an electronics perspective. What does "hit harder" mean, and why? Also, if you'd watched the video I referred to, the detail was there, but was not obvious, While Mark made a sweeping statement about low frequency was better for high conductors and vise-versa, he did not clarify it. The detail was in the VDI wheel and how frequency relates to it - and the discrimination circuitry (which really wasn't mentioned).
Note Mark said 1) The length of the arrows represent intensity. 2) the higher the frequency, the more target arrows point to the right, towards the +95 axis (all metals higher intensity). However, this crams all the high VDI numbers together, towards the +95 axis, which is real close to the -95 axis coming up from the bottom. If your ground balance is near -95 (near +95 on the wheel), then you lose sensitivity to the +95 signals due to the "wrap around" of the circuitry. Another way of putting it - your discrimination has only a couple of VDI numbers to work with. An analogy would be setting discrimination to +24, when nickels are +26 - you would then lose sensitivity to nickels due to the lesser ability of the circuitry to differentiate between the two. That is why you normally set your discrimination to JUST reject nails not further. This is the real reason silver coins are "hit harder" with the low frequencies - due to the discrimination circuitry, not the frequency itself. Does this make sense?
George
I understand that nowhere in the original post that was asked is the word WHY used. The question was asked and answered.
Making the statement that Carl's post was not technical and misleading is ridiculous. As an owner of a Whites product I read the Whites forum and am not chasing you around the forum.
Also the DFX transmits both frequencies in single frequency unlike the V3i which is a true single frequency detector. On this forum I am not concerned with the DFX.
Since the post was answered and there is no more to say I am closing the post. Start a new post if you want to discuss VDI wheel or wrap.
Making the statement that Carl's post was not technical and misleading is ridiculous. As an owner of a Whites product I read the Whites forum and am not chasing you around the forum.
Also the DFX transmits both frequencies in single frequency unlike the V3i which is a true single frequency detector. On this forum I am not concerned with the DFX.
Since the post was answered and there is no more to say I am closing the post. Start a new post if you want to discuss VDI wheel or wrap.