blowfly1967
New member
to-day i was told by a seller of metal detectors,that if you want to find coins,you should use a vlf in the vicinty of 2.5 khz.is this true?i thought that the optimum frequency was 12.5 khz.hh blowfly,see ya
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operating frequencies?:ausflag:
- Thread starter blowfly1967
- Start date
I a thr
Member
I have used many machines with many freq. and they all will find coins. From my own personal experience the two detectors that have found the most, oldest and smallest silver have been the Musky Advantage at 5.5 KHz and the XL Pro at 6.59 KHz. Like I said I have found coins with ever detector I have had but these two have really proven for me. IMHO!
I do need to get a 3 KHz for my X 705 and give it a whirl as have heard good things about it and silver coins.
I do need to get a 3 KHz for my X 705 and give it a whirl as have heard good things about it and silver coins.
BarberBill
New member
I've found LOTS of coins with my MXT which is near 15Khz and with my 10 Khz Tesoros.
HH
BB
HH
BB
As Mr Bill said, George Payne invented/designed almost every feature found on modern VLF detectors, below is what he has said and written about transmit frequencies and how they respond to targets in different conductance ranges.
"The target signal returned to the receive coil can be thought of as composed of two components, one we call x and one we call r. The polarity of the x signal (its direction) tells us if the target is ferrous or non-ferrous. The r signal has only one polarity. Also, the ratio of the x and r signal tells us the target’s phase. In addition, the signal magnitude (which relates to sensitivity) of both x and r are a function of operating frequency.
The x and r target signals are frequency dependent and obey very predictable characteristics when the operating frequency changes. We know that the x component decreases as the operating frequency decreases. Above a certain frequency the x component reaches a maximum. The r component acts differently. It is maximum at one particular frequency and decreases if you go up or down in frequency. We call the special frequency at which the r signal is maximum, the target’s -3db frequency. It also turns out that at the -3db frequency the x signal is one-half of its maximum value. This special frequency is unique to each target and is different for different target.
The higher the conductivity of the target the higher will be the targets -3db frequency. Conversely, the lower the conductivity the lower the -3db frequency. The -3db frequency of the high conductivity target will also make the r signal peak at a high frequency, normally well above the operating frequency of the VLF detector. This will make the high conductivity target have lower sensitivity on the VLF detector because the r signal amplitude drops if we are significantly below the -3db frequency. Simply put, maximum sensitivity on a VLF detector would be if we position the operating frequency directly at the target’s -3db frequency. For example, a dime and penny have a -3db frequency of about 2.7KHz. This is where their r signal peaks and would be the best frequency for picking them up using a VLF detector. However, a silver dollar has a -3db frequency of 800Hz. Nickels, on the other hand, have a -3db frequency, where its r peaks, at about 17KHz. Targets like thin rings and fine gold are higher still. Clearly there is no one frequency that is best for all these targets. The best you can do is have an operating frequency that is a compromise. Generally we can say that high frequencies are best for low conductivity targets and low frequencies are best for high conductivity targets."
George Payne, Copyright
"The target signal returned to the receive coil can be thought of as composed of two components, one we call x and one we call r. The polarity of the x signal (its direction) tells us if the target is ferrous or non-ferrous. The r signal has only one polarity. Also, the ratio of the x and r signal tells us the target’s phase. In addition, the signal magnitude (which relates to sensitivity) of both x and r are a function of operating frequency.
The x and r target signals are frequency dependent and obey very predictable characteristics when the operating frequency changes. We know that the x component decreases as the operating frequency decreases. Above a certain frequency the x component reaches a maximum. The r component acts differently. It is maximum at one particular frequency and decreases if you go up or down in frequency. We call the special frequency at which the r signal is maximum, the target’s -3db frequency. It also turns out that at the -3db frequency the x signal is one-half of its maximum value. This special frequency is unique to each target and is different for different target.
The higher the conductivity of the target the higher will be the targets -3db frequency. Conversely, the lower the conductivity the lower the -3db frequency. The -3db frequency of the high conductivity target will also make the r signal peak at a high frequency, normally well above the operating frequency of the VLF detector. This will make the high conductivity target have lower sensitivity on the VLF detector because the r signal amplitude drops if we are significantly below the -3db frequency. Simply put, maximum sensitivity on a VLF detector would be if we position the operating frequency directly at the target’s -3db frequency. For example, a dime and penny have a -3db frequency of about 2.7KHz. This is where their r signal peaks and would be the best frequency for picking them up using a VLF detector. However, a silver dollar has a -3db frequency of 800Hz. Nickels, on the other hand, have a -3db frequency, where its r peaks, at about 17KHz. Targets like thin rings and fine gold are higher still. Clearly there is no one frequency that is best for all these targets. The best you can do is have an operating frequency that is a compromise. Generally we can say that high frequencies are best for low conductivity targets and low frequencies are best for high conductivity targets."
George Payne, Copyright
blowfly1967
New member
i think this has soundly answered my question and now i have to repeatly read this post to make it sink into my aging brain so i'll be ready for the next person who thinks he knows more than me and tries to give me a hard time!! blowfly
Man, I wish I new 1/8 of what you guys know. I have no idea what you are talking about. Guess that is what all newbees would say. I'm just a 55 yr old midwest Indiana boy with only a 12th grade education, so its all over my head. I will probably never understand it all, but I sure have fun with my new hobby.
Carolina Phil
New member
I don