Which Of These 3 Coils For Underwater Work?

[pjrough]

I am starting a new project for getting land TDI sl waterproofed. It will be a long story for sure, but I ended up in the same situation and decided to go for Detech 8” Mono.

got my coil delivered to me a couple of days back.

[Tony]

10 hours ago, RickUK said:

I use the 8'' Garrett Mono coil on my 'Crossbow' pulse works exceptionally well,also have the 14x9 coil as well,both work well but the 8'' is my favourite out of the 2.Very good depth and also good for smaller targets like jewellery etc.

That’s good to know......8” is such a good size for the rougher water and poor viz 

[Tony]

9 hours ago, kac said:

Foam filled solid coil might be hard to swing in the water and might be too buoyant. I have used the 8" Garrett mono on my SHMK2 and it handles nice in the water. There is also the 10x14 mono that gives bit more depth and covers more area but I find it hard to pinpoint with, usually end up using the edges of the coil to narrow my dig.

Do want to point out that the Garrett coils can be prone to chipping if you bang them good. Wish they made a coil cover for it.

Thanks Kac......The buoyancy problem with a smaller 8” foam filled coil is probably okay as I got by alright with the bigger 12” dual field...it was more the resistance and coil flop that was the problem in rough water. All of my coils are coated several times with Plasti-Dip.......great protection from rocks.

[Tony]

3 hours ago, pjrough said:

I am starting a new project for getting land TDI sl waterproofed. It will be a long story for sure, but I ended up in the same situation and decided to go for Detech 8” Mono.

got my coil delivered to me a couple of days back.

Keep us posted on this project......sounds very promising 👍

[kac]

Both Garrett mono coils work well really well in the water, I do kind of favor the 8" over the larger one. That's a good idea on the dip, might patch the chip and coat it all. I have some truck bed liner coating that should be good.

[Skull diver]

As an 8" lover, I was strongly interested to buy the Garrett one mostly for the open shape and its underwater epoxy filled nature.

Some of the tech experts here on the board were nicely explaining the different kind of coil compared with a plain mono for the Tdi.🤤

So the choice was then limited between the Coiltek Platypus 12x8 and the Detech which was an unbeatable winner for price..

Then I tried for the Coiltek to have one, but forced to ask in my area for someone to sell it🤬.I'm a strong defensor of equal price on the globe for anyone...I don't like to overpay for the same stuff otherwise feel like fooled.

So the Detech was the last of my options but I already had to deal with the Coiltek 10x5" buoiancy on the Ctx and I can't accept the handling of closed design coils.No more.

All of this effort to obtain (probably) a couple less delay points on the knob?

Also, there's another factor...Must be hardwired on the board otherwise more noise can added to the already usual bouncy retuning scream...

So I decided to take a breath and leave the world as it is.

 

 

[Tony]

Detector  is now disassembled.....very easy but I took plenty of photos of the board layout just to be sure. Two points were desoldered (second photo) and the coil wires slipped out nicely. Just waiting if I can get the 3 spoke coil sent to me. Some pictures of the surgery........I will add that replacing the gasket is a bit tricky but make sure it goes on dry and no silicone grease on the gasket. Once the gasket is seated I find that adding a thin coat of silicone grease to the top cover where it seats with the gasket helps slide the cover on evenly and prevents any gasket bunching up. Only tighten the screws enough to slightly compress the oring.....do not over tighten otherwise the plastic tabs can crack. Tighten the screws a bit at a time and from side to side checking how well the gasket is seating.

Stage 2 hopefully soon 👍

[pjrough]

 

Tony, good luck with your project.

Can I ask you to make a good photo if the PCB front side?

Can you also show where the headphones were plugged to?

 

I still have to decide whenever I will go for piezo or dynamic head speakers for my TDI project. But it nice to compare PCB, so I can track where to plug the piezos.

 

Here are two different pcb's older is from 2011 and newer is from year 2016.

[Tony]

12 minutes ago, pjrough said:

 

Tony, good luck with your project.

Can I ask you to make a good photo if the PCB front side?

Can you also show where the headphones were plugged to?

 

I still have to decide whenever I will go for piezo or dynamic head speakers for my TDI project. But it nice to compare PCB, so I can track where to plug the piezos.

 

Here are two different pcb's older is from 2011 and newer is from year 2016.

I’ll take those photos for you tomorrow in the daylight  👍

[Skull diver]

You're inspiring me Tony!

I 'm wondering if the 8" AQ1 coil  can match the needed inductance