Making A Drag Coil From Scratch

[phrunt]

5 minutes ago, Northeast said:

Have also just seen these  -  https://detectormods.com/shop/77/flexible-drag-coil   

Wow, that seems just what you are after, I can't imagine they're very sensitive but if you're chasing some big stuff, I wonder if they'll hit a 2 grammer with any depth.

They look nice and light and all you'd need to do is make a suitable skid plate it seems.

[Northeast]

32 minutes ago, phrunt said:

Wow, that seems just what you are after

It is pretty much exactly what I had in my head - and it is already made with all of the bugs ironed out. 

It takes away the learning and the fun but it lets me get on and use it and work out how best to run it before W.A. next year. 

A vid about it here.  Make it a long oval shape rather than round and the 50" coil could be roughly 25" X 65"  💪

 

 

Might need to change the heading of the thread  😂

[phrunt]

I like the way he explains how the AI coil works, Good luck with it all Northeast, at least it's a cheap and easy for you now so hopefully it makes your next trip a successful mission.

[GotAU?]

Something rigged up like Jim Straight using this Bismarck coil by Jim Stewart for a Coiltek Mothership 40x20 coil, or mounting it on a plastic cart made with PVC tubes may work better…

[Ridge Runner]

Northeast  

 Go to this site called hotfootrug 

.com 

  This coil is a blanket that you can drag behind just about anything you want.

 Chuck 

[Ridge Runner]

Northeast  

Under the picture it says find a 1/2 ounce nugget at 4 ft without getting off your quad .

 I’ve got the Brooklyn Bridge for sale but do you want it with pigeons are not.

 All I’m saying is seeing is believing but you got to spend the money to find out if it’s true.

 Maybe be best if I come down and dig for you.haha

 Chuck 

[jasong]

Are you aiming to cover ground or aiming for depth on patches? Seems to me those large drag coils are mostly for depth on patches and not ground coverage, especially not being towed. But maybe I misunderstand them due to not having used one.

I tried a 25" round and gave that up as too large for exploration because it was slower to swing and produced too many spurious signals that caused lots of lost time investigating, and investigating each target was laborious due to coil size. So one even larger seems like it may come with the same problems for covering lots of ground. 

You probably already know about these NF 30x7" Patch Pros and eliminated them, but here's one if not - swiped this from Rob's site. I haven't tried one my self so take what I say with a hefty grain of salt. If ground coverage is the key and not depth, then more elliptical is better (large swath coverage, but skinny so quicker to locate targets, less EMI per area swath coverage). This one has the area equivalent to a 15" round roughly, so the EMI should be about equal too, and a 15" is ok for exploration IMO. The EMI/spurious signals on coils like 20 or 25" rounds increase quite a lot (especially on uneven ground where the coil is at an angle)...on a big drag coil it seems like you might be chasing ghosts often all day, and that means less ground coverage. Just a guess though, I could be totally wrong. And we definitely have worse EMI issues here so that may just be a big problem for us and not for you. 

The other consideration is if you are working salt ground then you want to minimize your total coil area too, and in those cases and extreme elliptical shape is the best too since total coil area is small relative to swath coverage. 

Just another thought to toss out there anyways.

 

[phrunt]

Ply would add a lot of weight so I don't really like that idea if you're walking along dragging it, I'd personally make a poly carbonate skid plate to use as a way to mount the coil in it, I'd drill and use cable ties to hold the winding in place where I wanted it and If I never wanted to change it's position I'd put some glue down too, even just hot glue so it can be removed easy enough and I'd attach small round conduit PVC piping to the bottom of the skid plate to drag it around in the front, middle and back, I'd use something like Nylon rivets to hold the poly skid plate onto the PVC pipe, plenty of them.

If the PVC pipe ended up too hard to drag little plastic wheels could be added to the ends of it using plastic screws.

 

[Northeast]

8 hours ago, GotAU? said:

Jim Straight’s Bismarck coil for a Coiltek Mothership 40x20 coil

Thanks GotAU.  Although that set-up is weighted better I'm trying to find an alternative to the side-to-side swinging motion.  Walking/pulling in a straight line seems like it would be better on the body long term  👍

7 hours ago, Ridge Runner said:

This coil is a blanket that you can drag behind just about anything you want.

Actually seems like a decent option RR, thanks.  Made in Idaho - I wonder if @Gerry in Idaho has seen them out and about?  Looks like you have to use their P.I. module though.  And shipping to Australia - I don't even want to know 🤣

5 hours ago, jasong said:

Are you aiming to cover ground or aiming for depth on patches?

Definitely ground coverage in the first instance Jasong.  Depth is just an added advantage.  

 

However, I think the option below will give me both.  It could be laid out in a wide oval shape to get ground coverage.  Then, if a patch is found or I wanted to go over the B-I-L's original patch (found 1/2 a kilo and counting) then it could be shaped into a 50" round coil.   

https://detectormods.com/shop/77/flexible-drag-coil

 

 

[GotAU?]

1 hour ago, Northeast said:

Thanks GotAU.  Although that set-up is weighted better I'm trying to find an alternative to the side-to-side swinging motion.  Walking/pulling in a straight line seems like it would be better on the body long term  👍

 

 

How about pulling the 40x20 CT Mothership coil sideways on a little PVC pipe cart or sled?