Building Custom Coils For Gold Bug 2?

[LRM]

Has anyone on this forum gone about the process of designing their own custom coils to go with some of the more popular detector models on the market?

I only have a Gold Bug 2 at the moment and it does alright for what I purchased it for but I was wondering if I might be able to get some more coverage and detection ability out of it when I take it down to the beach I live near to see if the rich people have lost anything. It does just fine out in the desert with the stock 6" coil and I have never felt the need to buy one of the larger coils as I just do not think those would really fit how I most use the detector out in the desert.

Anyway I obviously am considering trying to build a couple different sizes and geometry coils to use with my GB2 but also would love to hear about what other people have done with other detectors.

Would love to get a little more guidance than my sorta basic electronics knowledge, intuition, and searching the web.

[PimentoUK]

You should register with the Geotech1 Forum, where you will find an abundance of info about coil building:

Geotech1 forums

Unfortunately, the GB2 is one of those "difficult" coils. The combination of high operating frequency, and internal components ( tuning capacitor etc ) , and the fact no-one seems to have reverse-engineered one, means your chance of success are low.

I think the GB2 is not the best choice for beach detecting, due to its high operating frequency, and inability to handle the electrically-conductive salt-water sand. It would be better to buy a new machine dedicated to beach hunting, preferably with some degree of water-resistance as a feature.

[RickUK]

In theory it sounds interesting,but in reality would not be the best way forward as single freq machines are not the best option for wet beach sand,so in my mind it would be a total waste of time....the best way forward if you want to do your own coils would surely do a PI kit which can be purchased pretty cheap infact very cheap and then make the coil which is pretty easy and alot easier than VLF coil designs.

All ready that has been suggested is the Geotech1 forum,some serious electronic boffins on that forum,regarding the Gold Bug2 i personally think it would be a total waste of time going down that route.

[LRM]

7 hours ago, PimentoUK said:

You should register with the Geotech1 Forum, where you will find an abundance of info about coil building:

Geotech1 forums

Think I may have an account on there from a few years ago...will have to see if I can remember the username.

7 hours ago, PimentoUK said:

I think the GB2 is not the best choice for beach detecting, due to its high operating frequency, and inability to handle the electrically-conductive salt-water sand. It would be better to buy a new machine dedicated to beach hunting, preferably with some degree of water-resistance as a feature.

Totally agree that it is not the best choice but I am not buying a new detector when I plan to be leaving the area for good in the next year or two.

The majority of where I have used it on beaches in the past is on the dry sand areas near high end hotels and resorts with beach seating areas far from the water's edge. I was concerned about the salt in the sand even with it being dry but it did not cause me too much trouble. Would not even consider using that detector down near the water at all for obvious reasons.

[LRM]

6 hours ago, RickUK said:

In theory it sounds interesting,but in reality would not be the best way forward as single freq machines are not the best option for wet beach sand

I have no plans to use the detector or really any detector on the wet beach sand. Plenty of more valuable target rich areas in the dry sand areas here in Southern California than down near the water's edge.

[PimentoUK]

There is a larger coil made for the GB2, similar shape to the 6", but about 10" long? Perhaps it may be worth looking out for one of those.
As they are official Fisher products, there's a good chance they have geometry that's deemed correct for the machine. Putting a round 15" DD on a 72 kHz machine, for example, may just prove disappointing ( big coil says 'big targets' , 72 kHz says 'small targets' ).

[kac]

Many of the modern machines have circuits in the coil so it would be impossible to build a coil for those without the specs and schematics on them. Other issue is finding the cable connectors as some are proprietary.

You will need to reverse engineer coils that you can get connectors for to figure out what is the Tx and Rx pinouts and the ohms and impedance of them.

As Pimento mentioned Geotech forum may be able to help.

[LRM]

25 minutes ago, kac said:

Other issue is finding the cable connectors as some are proprietary.

You will need to reverse engineer coils that you can get connectors for to figure out what is the Tx and Rx pinouts and the ohms and impedance of them.

Does not sound like it will help anyone here but the connector for the Gold Bug 2 coils is a Switchcraft SL405MX which will run you about $15 from any electronics part retailer.

[kac]

12 hours ago, LRM said:

Does not sound like it will help anyone here but the connector for the Gold Bug 2 coils is a Switchcraft SL405MX which will run you about $15 from any electronics part retailer.

See if you can pick some brains over at Geotech. Maybe someone there might know the specs for the coils and pinouts.

As for wet sand an eliptical dd may serve you better and be more stable than a round dd.

I use my Gold Racer at the beach and just manually ground balance it. I use it for the towel lines and cuts as the really wet sand here is all wash.

[Steve Herschbach]

From Geotech:

Coil Basics by Carl Moreland

Construction of Coplanar Search Coils - An easy method of making coplanar-concentric search coils

Coil Winder - How to make a device that will wind coils from 3 inches to 24 inches in diameter

Making a Fast Pulse Induction Mono Coil - An easy method for making fast PI search coils

The three Gold Bug 2 coils are all concentrics. A DD coil was prototyped but never went into production.