I been using the Sovereigns since 1996 and use the Sun Ray DTI meters which is said to be a volt meter and with Ron's meter it is a volt meter. Now these meters are very accurate once you know your Sovereign well. With these digital meters they do measure the voltage of the return signal and the tones that are so close to tell with the tones the Sovereign gets so the meter can and will tell the difference. To me when I get a 179-180 meter reading it is telling me it is probably a copper penny, or clad or silver dimes or quarters or even a half it is seeing. a 176-177 tells me it can be a zinc penny or even a IH penny and some of the early Wheaties will read here too.. Now nickles seem to have a tone all to there selfs and read 143-145 and the war nickles can read up to 151, but they have the nickle tone to them. The round pull tabs read in this area too, but don't have the nickle tone, but close. The beaver tails off the old round pull tabs will read 140-141. by using the meter with the tones I find I do dig a few pull tabs but nowhere I do with any other detector. Like I say the Sovereigns with the good 180 meter is the most accurate coin detector I have ever seen and have some great coins and jewelry finds in many places that have been well worked over the years.
Rick
