Let me start with some of your closing comments first and take it from there:
Right here you stated you plan to "dig it all" and that is best accomplished by:
• Long-term commitment
• Making small, yet effective grids of the site
• Use of a model with a true, Threshold-based All Metal mode
• Slowly and methodically working each grid (something like maybe 6'X10') from at least two directions
• Overlapping the search coil on each advancement by moving forward no more than the diameter of a US Dime
• Making no less than 3 passes on each sweep route prior to coil advancement
• Recovering ALL target responses, even if only from one direction, and be sure to recover very weak signals as well as soft, moderate or strong audio responses
• Relying ONLY on the audio response and never referring to the visual TID display for a dig/no-dig decision
These eight steps can be performed using ANY detector you currently have that features a Threshold-based All Metal mode ... if you plan to "dig it all" and not leave any targets behind.
It would make a great report to share on a few Forums once you accomplish that task and describe the amount of time and effort devoted to such a project and the results you had. It would be especially interesting if you indicated the number or trash targets recovered as well as desired targets recovered per individual marked grid. Very educational for many newcomers to this hobby.
Now, if trying to decide how to get it all and not just 'cherry pick' for select higher-conductive coins, then we've covered most detector choice needs:
1.. Gridding the entire site into marked 6 foot X 10 foot grids.
2.. Using a Threshold-based All Metal search mode.
3.. Using a versatile and efficient deeper-seeking coil such as a 'standard' size as mentioned.
4.. Covering each grid from at least two different directions.
5.. Overlapping after 2-3 sweeps across one sweep route by no more than the diameter of a Dime.
6.. No use of visual TID, only making sure to recover ALL targets, providing even just a one-direction audio response.
All of this can be accomplished with ANY make or model detector in a Threshold-based All Metal mode. The amount of time and effort required to achieve the goal of total metal target recovery could be attempted following all of the above suggestions, leaving only one question to be answered:
I could use a Tesoro Bandido II µMAX at 10 kHz and a Vaquero at 14.5 kHz for slightly different results.
There would be only a subtle difference between a 14 kHz Makro Racer/Racer 2 and 15 kHz Nokta FORS CoRe, but you could use a 14 kHz Racer or 15 kHz CoRe and then re-hunt the entire gridded site with a 19 kHz FORS Relic for a chance at pulling a few extra missed targets out.
Considering this approach or the one using the two Tesoro models, the site would be gridded and hunted with a standard-size search coil with a moderate-range frequency [size=small](10 kHz to 15 kHz)[/size] and a higher-range frequency [size=small](something in the 18 to 20 kHz range)[/size], and that would be very good.
But perhaps the best approach would be to grid the entire park off a 3rd time for a thorough search using a lower-end frequency in the VLF range [size=small](roughly 4 kHz to 8 kHz)[/size]? If so, the Nokta Impact would make the logical choice in detector selection because you have the option of selecting 5 kHz, 14 kHz or 20 kHz so as to work the gridded location, completely, in one of each frequency group in the VLF range. So, get a Nokta Impact, use the 'standard' 7X11 DD coil, make a gridding device so you can mark and completely cover each grid
♥ - from at least two directions ... using each of the 3 operating frequencies ...
♦ - always advancing no more than a Dime's diameter after 2-3 sweeps each direction
♣ - recovering each and every audio response target
♠ - and making notes on each recovery, or at least a report of the total recoveries, per grid, at each of the three operating frequencies
If you have a nice, small, square-shaped park of about 100 feet by 100 feet, we should get your final gridding report next year.
Consider thorough gridding for a moment. We have had some smaller-size coins in regular circulation here in the USA during the past 130 years [size=small](the age of your park)[/size] such as a Half-Dime, silver type 3¢ piece, nickel type 3¢ piece, $1 and even $2.[size=small]50[/size] gold coins, if we are considering coins smaller than the common US 10¢/Dime coin.
A Dime measures almost ¾" in diameter. If you do not want to miss a Dime, you should advance your coil no more than 50% of that diameter, but we can be a little more forgiving and say advance the search coil no more than ½" when overlapping. You should sweep each side-to-side sweep path at least 2 times and really at least 3 times before advancing the search coil to the next sweep path.
If you make a short 24 inch side-to-side sweep and allow 2 seconds per sweep from one side to the other, then it will take a minimum of 6 seconds to make 3 side-to-side sweeps of that ½" wide path. If you have a small 2 foot by 2 foot square grid to search, thoroughly, then you would sweep left-to-right and right-to-left plus one more pass from either direction [size=small](3 passes)[/size] is no less than 6 seconds to cover ½" of that 24 inch square, and it will take a continuous sweeping of 288 seconds to sweep each ½" path [size=small](48 paths)[/size] to cover 24" going forward. If you then immediately turned 90° and re-covered that same 24" X 24" square again, thoroughly, it will take another 288 Seconds for a total search time of 576 Seconds. Thus, it would require you to spend 9.[size=small]6[/size] Minutes to completely and efficiently cover a 24" square from 2 opposing directions.
Now, let's remember that you will have to pause briefly when you stop to reverse direction, and make incremental partial steps to advance the coil to completely cover the grid, and time for movement to move to the side of the grid square to cover it from a 90° angle, so let's be generous and figure that other than actual scanning time you needed an additional 1.[size=small]4[/size] Minutes for your physical movements and positioning, and that would then mean you could completely cover a 24" by 24' grid, from 2 different directions, in 11 Minutes.
If you have a very small park, or private yard or other dedicated sport to "dig it all" and not cherry pick, and you marked it off in 24 inch [size=small](2 foot)[/size] squares, then that would divide the 100'X100' grassy area into 50 2 foot grids by 50, 2-foot grids, making a total of 2500 separate grids [size=small](50 X 50)[/size] to be searched.
If we allowed a best time of 11 Minutes per 2'X2' grid, and you want to cover 2500 of grids, then that would require 27,500 Minutes. This would not include moving grid markers, moving from one 2' square grid to another, taking a break, eating a meal, getting any sleep, changing batteries, going potty or any other time delay. Just 27, 500 Minutes to cover the 10o foot by 100 foot park/yard/area, from two directions, uninterrupted. And 27,500 Minutes equals 458⅓ Hours. Uninterrupted.
Then you have to factor in the time to get down for target recovery, the time and effort to recover the target and tidy the recovery site, then get back up, drop the target in your pouch and start hunting again. If you are using an All Metal mode to get a signal on every target present, then let's just guess you will find ferrous and non-ferrous targets and maybe 'average' a recovery of 5 metal targets per 2'X2' grid. Maybe you can move easier than me or others with some mobility issues like me and you could get a signal, isolate [size=small](pinpoint)[/size] the target and get down to make the recovery, clean up, and be back into search position in 1 minutes or less per target. So 5 targets per grid, easy to do if finding ALL metal objects to be recovered, would require another 5 Minutes of time devoted per grid.
Remember, there are 2500 of the 4 ft. sq. grids in that 100 ft. by 100 ft. area, such as a really small 100 foot square park, so that's another 12,500 Minutes required for recoveries. That equals another 208⅓ Hours to completely remove ALL targets from a 100'X100' area making a total search and recovery time of 666⅔ Hours, so let's just round that off to 667 Hours.
One efficient gridding of ALL metal targets in a 100 foot by 100 foot grid and recovering 5 targets per 2'X2' grid [size=small](quite possible when getting ALL ferrous and non-ferrous targets in a well used, 130 year old park)[/size] will require at least 667 Hours, to work from two directions ... with ONE operating frequency. Do it with 2 different frequencies or 3 different frequencies and that's going to take even longer!
I you happen to have an 100'X100' park, yard, school or any other human activity site that is 130 years old and there are NO targets to be recovered at all, then the least amount of time to cover it would be the 458⅓ Hours at one frequency. To re-hunt the same area without any metal targets to recover using 2 frequencies would then need 916 Hours, and with 3 frequencies it would need 1375 Hours.
One complete coverage at 1 frequency at 458⅓ Hours = 19.10 Days
Two complete searches using 2 frequencies and taking 916 Hours = 38.20 Days
Three complete searches using 3 different frequencies that takes 1375 Hours = 57.3 Days
Uninterrupted ... Without a single target hit to be recovered ... Non-Stop for sleep, food, or anything, it would require a LOT of time. Multiply this coverage of a 100'X100' space by the actual size of any dedicated area you would like to scour for anything and everything and a person would be quite busy for a long, long time.
I still grid small, dedicated areas and have my grid rope and stakes along with me in my detecting tote just in case I need them. However, I gave up long, long ago on any decision to grid off an entire park or school, or even most private yards ... unless they presented a very exceptional potential and were reasonably small enough..
Just some thoughts on the idea, so first grid a small area, use what you have, hunt in All Metal with a standard coil and determine if it is really worth it. If you live in a small size town, far away from a lot of other sites, and you wanted to just stay close to home and grid rather than drive around a lot, it might b a consideration.
Monte
[size=small]PS: I was trying to get this reply typed up during the night to get away for some detecting, but was very tired. I should have slept, and I might have erred in my quick math calculations, but I don't think I did. Excuse me if there's blooper[/size].
[size=small]PS-PS: Maybe just stick with 'Cherry Picking' or being a little more generous on target response selection and make use of the smaller-size coils to unmask potential keepers.[/size]
"Cherry Picking" is an art unto itself and is limited by many variables, to include the type of site, type of trash and/or trash density, what targets the operator plans to 'cherry pick' [size=small](such as any potential coin or just those that are higher conductors)[/size], and how selective the operator is with regard to the use of Discrimination, coil choice by size and type, reliance of audio Tone ID and visual Target ID display info, etc.Southwind said:
Right here you stated you plan to "dig it all" and that is best accomplished by:
• Long-term commitment
• Making small, yet effective grids of the site
• Use of a model with a true, Threshold-based All Metal mode
• Slowly and methodically working each grid (something like maybe 6'X10') from at least two directions
• Overlapping the search coil on each advancement by moving forward no more than the diameter of a US Dime
• Making no less than 3 passes on each sweep route prior to coil advancement
• Recovering ALL target responses, even if only from one direction, and be sure to recover very weak signals as well as soft, moderate or strong audio responses
• Relying ONLY on the audio response and never referring to the visual TID display for a dig/no-dig decision
These eight steps can be performed using ANY detector you currently have that features a Threshold-based All Metal mode ... if you plan to "dig it all" and not leave any targets behind.
Yes, it is a good place because I believe a lot of savvy detectorists handle Nokta brand detectors, outnumbering the more casual hobbyist-level detector users.Southwind said:
This ought to be a great project to take on a 130 year old park. I have done similar scourings of small sections of old parks or other popular activity sites, but not an entire park. I don't have that long to live to devote to such thoroughness at one whole park. It would help, too, if the park or dedicated site is of a more squared design so that you can more easily grid it off. I know several of the older-use parks I would like to work that way are so uneven in their contour that 'gridding' would be more difficult.Southwind said:
It would make a great report to share on a few Forums once you accomplish that task and describe the amount of time and effort devoted to such a project and the results you had. It would be especially interesting if you indicated the number or trash targets recovered as well as desired targets recovered per individual marked grid. Very educational for many newcomers to this hobby.
I have the Racer 2, as well as a couple of Impact's, a couple of FORS CoRe's and three FORS Relic units. I also have four Tesoro models, with various search coils. Smaller-size coils would be best to use for 'cherry picking' in very trashy spots, but a 'standard' coil, such as the 7X11 DD on any of the Makro or Nokta models, or the 8X11 DD on my Tesoro Vaquero, would provide the best depth of detection and coverage. Since all coils, regardless of size, would only be advanced the diameter of a dime during thorough coverage, and since ALL targets would be recovered, it might as well be tackled with a 'standard' size search coil.Southwind said:
Now, if trying to decide how to get it all and not just 'cherry pick' for select higher-conductive coins, then we've covered most detector choice needs:
1.. Gridding the entire site into marked 6 foot X 10 foot grids.
2.. Using a Threshold-based All Metal search mode.
3.. Using a versatile and efficient deeper-seeking coil such as a 'standard' size as mentioned.
4.. Covering each grid from at least two different directions.
5.. Overlapping after 2-3 sweeps across one sweep route by no more than the diameter of a Dime.
6.. No use of visual TID, only making sure to recover ALL targets, providing even just a one-direction audio response.
All of this can be accomplished with ANY make or model detector in a Threshold-based All Metal mode. The amount of time and effort required to achieve the goal of total metal target recovery could be attempted following all of the above suggestions, leaving only one question to be answered:
►►► What operating frequency would work the best? ◄◄◄
I could use a Tesoro Bandido II µMAX at 10 kHz and a Vaquero at 14.5 kHz for slightly different results.
There would be only a subtle difference between a 14 kHz Makro Racer/Racer 2 and 15 kHz Nokta FORS CoRe, but you could use a 14 kHz Racer or 15 kHz CoRe and then re-hunt the entire gridded site with a 19 kHz FORS Relic for a chance at pulling a few extra missed targets out.
Considering this approach or the one using the two Tesoro models, the site would be gridded and hunted with a standard-size search coil with a moderate-range frequency [size=small](10 kHz to 15 kHz)[/size] and a higher-range frequency [size=small](something in the 18 to 20 kHz range)[/size], and that would be very good.
But perhaps the best approach would be to grid the entire park off a 3rd time for a thorough search using a lower-end frequency in the VLF range [size=small](roughly 4 kHz to 8 kHz)[/size]? If so, the Nokta Impact would make the logical choice in detector selection because you have the option of selecting 5 kHz, 14 kHz or 20 kHz so as to work the gridded location, completely, in one of each frequency group in the VLF range. So, get a Nokta Impact, use the 'standard' 7X11 DD coil, make a gridding device so you can mark and completely cover each grid
♥ - from at least two directions ... using each of the 3 operating frequencies ...
♦ - always advancing no more than a Dime's diameter after 2-3 sweeps each direction
♣ - recovering each and every audio response target
♠ - and making notes on each recovery, or at least a report of the total recoveries, per grid, at each of the three operating frequencies
If you have a nice, small, square-shaped park of about 100 feet by 100 feet, we should get your final gridding report next year.
Consider thorough gridding for a moment. We have had some smaller-size coins in regular circulation here in the USA during the past 130 years [size=small](the age of your park)[/size] such as a Half-Dime, silver type 3¢ piece, nickel type 3¢ piece, $1 and even $2.[size=small]50[/size] gold coins, if we are considering coins smaller than the common US 10¢/Dime coin.
A Dime measures almost ¾" in diameter. If you do not want to miss a Dime, you should advance your coil no more than 50% of that diameter, but we can be a little more forgiving and say advance the search coil no more than ½" when overlapping. You should sweep each side-to-side sweep path at least 2 times and really at least 3 times before advancing the search coil to the next sweep path.
If you make a short 24 inch side-to-side sweep and allow 2 seconds per sweep from one side to the other, then it will take a minimum of 6 seconds to make 3 side-to-side sweeps of that ½" wide path. If you have a small 2 foot by 2 foot square grid to search, thoroughly, then you would sweep left-to-right and right-to-left plus one more pass from either direction [size=small](3 passes)[/size] is no less than 6 seconds to cover ½" of that 24 inch square, and it will take a continuous sweeping of 288 seconds to sweep each ½" path [size=small](48 paths)[/size] to cover 24" going forward. If you then immediately turned 90° and re-covered that same 24" X 24" square again, thoroughly, it will take another 288 Seconds for a total search time of 576 Seconds. Thus, it would require you to spend 9.[size=small]6[/size] Minutes to completely and efficiently cover a 24" square from 2 opposing directions.
Now, let's remember that you will have to pause briefly when you stop to reverse direction, and make incremental partial steps to advance the coil to completely cover the grid, and time for movement to move to the side of the grid square to cover it from a 90° angle, so let's be generous and figure that other than actual scanning time you needed an additional 1.[size=small]4[/size] Minutes for your physical movements and positioning, and that would then mean you could completely cover a 24" by 24' grid, from 2 different directions, in 11 Minutes.
If you have a very small park, or private yard or other dedicated sport to "dig it all" and not cherry pick, and you marked it off in 24 inch [size=small](2 foot)[/size] squares, then that would divide the 100'X100' grassy area into 50 2 foot grids by 50, 2-foot grids, making a total of 2500 separate grids [size=small](50 X 50)[/size] to be searched.
If we allowed a best time of 11 Minutes per 2'X2' grid, and you want to cover 2500 of grids, then that would require 27,500 Minutes. This would not include moving grid markers, moving from one 2' square grid to another, taking a break, eating a meal, getting any sleep, changing batteries, going potty or any other time delay. Just 27, 500 Minutes to cover the 10o foot by 100 foot park/yard/area, from two directions, uninterrupted. And 27,500 Minutes equals 458⅓ Hours. Uninterrupted.
Then you have to factor in the time to get down for target recovery, the time and effort to recover the target and tidy the recovery site, then get back up, drop the target in your pouch and start hunting again. If you are using an All Metal mode to get a signal on every target present, then let's just guess you will find ferrous and non-ferrous targets and maybe 'average' a recovery of 5 metal targets per 2'X2' grid. Maybe you can move easier than me or others with some mobility issues like me and you could get a signal, isolate [size=small](pinpoint)[/size] the target and get down to make the recovery, clean up, and be back into search position in 1 minutes or less per target. So 5 targets per grid, easy to do if finding ALL metal objects to be recovered, would require another 5 Minutes of time devoted per grid.
Remember, there are 2500 of the 4 ft. sq. grids in that 100 ft. by 100 ft. area, such as a really small 100 foot square park, so that's another 12,500 Minutes required for recoveries. That equals another 208⅓ Hours to completely remove ALL targets from a 100'X100' area making a total search and recovery time of 666⅔ Hours, so let's just round that off to 667 Hours.
One efficient gridding of ALL metal targets in a 100 foot by 100 foot grid and recovering 5 targets per 2'X2' grid [size=small](quite possible when getting ALL ferrous and non-ferrous targets in a well used, 130 year old park)[/size] will require at least 667 Hours, to work from two directions ... with ONE operating frequency. Do it with 2 different frequencies or 3 different frequencies and that's going to take even longer!
I you happen to have an 100'X100' park, yard, school or any other human activity site that is 130 years old and there are NO targets to be recovered at all, then the least amount of time to cover it would be the 458⅓ Hours at one frequency. To re-hunt the same area without any metal targets to recover using 2 frequencies would then need 916 Hours, and with 3 frequencies it would need 1375 Hours.
One complete coverage at 1 frequency at 458⅓ Hours = 19.10 Days
Two complete searches using 2 frequencies and taking 916 Hours = 38.20 Days
Three complete searches using 3 different frequencies that takes 1375 Hours = 57.3 Days
Uninterrupted ... Without a single target hit to be recovered ... Non-Stop for sleep, food, or anything, it would require a LOT of time. Multiply this coverage of a 100'X100' space by the actual size of any dedicated area you would like to scour for anything and everything and a person would be quite busy for a long, long time.
I still grid small, dedicated areas and have my grid rope and stakes along with me in my detecting tote just in case I need them. However, I gave up long, long ago on any decision to grid off an entire park or school, or even most private yards ... unless they presented a very exceptional potential and were reasonably small enough..
Just some thoughts on the idea, so first grid a small area, use what you have, hunt in All Metal with a standard coil and determine if it is really worth it. If you live in a small size town, far away from a lot of other sites, and you wanted to just stay close to home and grid rather than drive around a lot, it might b a consideration.
Monte
[size=small]PS: I was trying to get this reply typed up during the night to get away for some detecting, but was very tired. I should have slept, and I might have erred in my quick math calculations, but I don't think I did. Excuse me if there's blooper[/size].
[size=small]PS-PS: Maybe just stick with 'Cherry Picking' or being a little more generous on target response selection and make use of the smaller-size coils to unmask potential keepers.[/size]
