How long to search a field?

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Easylife
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I was recently asked how long it took me to grid a 3 acre field?

I gridded this 3 acre field with the 15" coil and full ground coverage. My GPS track logs confirm over three visits how long it took me, what distance I covered and also visually shows how well I covered it.
So I walked 8600m x apx 1.5m swing = 12900sqm = 3.18 acres in 9h 40 min = 3 hrs/acre.
The GPS data usually tells me what with stopping to dig that my overall average speed is about 1 kmh (0.62 mph). Gee, that makes me feel like a snail but is for full coverage. Though if just having a general random wander about then is not as slow a walk but knowingly with ground missed between sweeps.
Of course figures will be dependent upon ground conditions, number of targets dug, etc.
How does that compare to yours? :?:
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Littleboot
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That is very interesting indeed. I must admit to being a bit of a casual wafter myself...unless I find a hotspot and concentrate on that area. i can't remember the last time I gridded anywhere properly....though sometimes I make a half-baked effort at self-discipline and follow crop lines. trouble is I usually drift after a while.
What interests me is the extrapolation of 3 hours per acre as a bottom line. I daresay there are people who take much longer but it is a very good rule of thumb. My average detecting session is 3 hours......and I have some very big fields. I don't tend to stop unless I am digging ....so it is all detecting time. (Whereas Pete, on the occasions he actually comes along with me....seems to spend eons of time leaning on his spade surveying the scene) So it really illustrates what a small proportion of a big arable field I actually waft over in a three hour session.
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Bors
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I never do gridding. I find it tedious and I`ve never found it provides the time spent ,worth the results .Probably because I search pretty barren area`s anyway so like Jan I tend to wander as a star and hope I strike it lucky as I toodle about :D .
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Dave The Slave
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Reckon I must be similar to 3hrs per acre.
Normally a 4hr session.
Like to grid for a couple of hrs, then freestyle.
If I had a field of say 50 acres, normally 18 to 25 visits a season, would probably last me at least 3 years but even then if there was no where else to go, it may have been ploughed or disturbed to make it like a new field.
So far not been on the same field for 2 seasons, due to crop rotation.
No hurry to detect, it will still be in the ground if no one else has access to the permission.
Good Luck everyone, :thumbsup: Dave.
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figgis
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Dave The Slave wrote: Tue Jul 21, 2020 4:09 pm Like to grid for a couple of hrs, then freestyle.
Bruvva fron anuvva muvva. Exactly that. :thumbsup: As Jan says, hotspots get gridded to within an inch of their lives and after that it's as Pete says - tedious. Consequently I go from careful snail to galloping wildebeeste without warning on most sessions.

Mark you, I say "gridded" when I actually mean try to overlap each swing then not be distracted by signals which cause memory loss as to where on the swing the signal occurred and which direction you were walking in when you got it.
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Oxgirl
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I know a two acre field took me way over 15 hours to detect with an 11" coil on a tram line style approach. Then I went back and spent another 8 hours doing it diagonally. So 23 hours or 12 hours per acre. It was a fun field to do with little rubbish on there.

In fact, now I've been reminded of that field, I might do a return visit one day soon, when they next mow it. I think my new coil and a deeper programme I'm now using might find more :D
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shaggybfc
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I always start with good intentions to walk systematically up and down, but then get a gut feeling great finds will be elsewhere so wander off.... I detect slowly, none of this speed detecting like a Tasmanian devil...
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Easylife
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Most of my fields are pasture, they all started off with a random wander or many even. But then I found which ones were consistently producing good finds so went on to grid them and found lots more. None of that ground is going to change from pasture any time soon, so when it's gone it's gone. :boom:
The less appealing previously wandered pasture fields still only justify a wander when only producing a few bits of scrap. There does need to be a good incentive to take the time to grid an area, like you have found several good finds there, or maybe a small non trashy undetected field as a personal project?
The trouble is that you can random wander a field forever and will still not know how much of it that you have actually covered (unless you use GPS tracking) and you will likely be going over much of the same ground multiple times. But the maybe more boring gridding approach is a more efficient way of covering an entire area if that is the plan. :feet:
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Easylife
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Oxgirl wrote: Tue Jul 21, 2020 6:56 pm I know a two acre field took me way over 15 hours to detect with an 11" coil on a tram line style approach. Then I went back and spent another 8 hours doing it diagonally. So 23 hours or 12 hours per acre. It was a fun field to do with little rubbish on there.
I think that a scattered hoard could warrant that. :moneybag:
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alloverover
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Personally I think this type of calculation is way out, unless its billiard table flat and your just swinging.
I get strange size parcels of land to play on quite often, for example, when I was doing a job during lockdown I had some land around the job, I would guess on average 8 meters wide and in a square of around 20 meters by 40meters, I make that about 960M2 so about a quarter of an acre.

For three days I was doing that area in my morning and lunch break, both of what I make sure is about an hour when ive got a bit of land to detect :P so, two hours a day for three days, 6 hours over a quarter acre, still getting lots of signals and not going over the same land ( much).
Having said that, a lot of the land is dug up and rough and also half of it is on a 1/3 batter, but even so, to get all the signals from an acre of land takes a long time in my opinion, and its only when you take that time that you really know whats there, ive been using the hf coil on the Deus lately and I reckon that would add about 50% extra time to searching with the standard black 9" and no matter what people might say, there is no machine that will get it all in one setting :thumbsup:
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Easylife
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alloverover wrote: Tue Jul 21, 2020 11:20 pm Personally I think this type of calculation is way out, unless it's billiard table flat and your just swinging.
Yep, too many variables, but gives you some idea based on your own set-up and land - mine was a quiet meadow. :thumbsup:
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Mucky
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I detect the same old fields time and time again. Very occasionally they surprise me.
Our hobby/pointless addiction, is a game of time in the field and patience. It's also a game of getting off your ass once in a while and finding a new permission. If you are addicted to excruciating disappointment after digging lots of holes, removing crap, and going to the pub sulking..
Then you have cracked it! That's what it's about... Dedication with a pinch of misery = success. :thumbsup:
I'll stop waffling now and get back to me pint. :silent:
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"How long to search a field?"

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Saffron
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I have seen 4 hours an acre quoted previously by somebody that is very methodical in the searching.

Evan
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