The Crossbow Classic PI

[Qiaozhi]

Thank you for quick reply.
Now I have no idea what to say.
I am happy to pay for new DD coil for this detector and to change the coil connections and add resistors etc.
But now I just do not know what to say.
All I want to do is add a DD coil. Please can you suggest one that is 15" diameter?
Thank you

I'm not aware of any 15" round DD coils that are suitable, but I do know that a Garrett Infinium LS DD coil (14"x10") will work.

Also, you might want to look at Detech -> https://www.detech-metaldetectors.com/products.html
where they sell 21"x17", 18"x15", and 15"x12" SEF coils suitable for Minelab GPX.

[TowySalmon]

Thank you once again.
I have contacted Detech. They seem (from what I read online) to have possibly two other coils that may be suitable; a 15" Spiral and 18" Open Design, meant for the GP, GPX amd SD series..
I will update here as soon as I hear back from them.
Again, many thanks, all your help is greatly appreciated.

[keith777]

Since it's based on a PCB design I sent to Sven, it should have the same performance as the original. I've no idea how many clones have been produced, maybe Sven knows. I don't think there were many, as it's quite a complex design for many people to duplicate.

From the eBay photos, it looks like the battery pack was replaced by a larger capacity Li-ion type, and there were some other quite minor modifications.

so does that make mine more of a unique crossbow and like hens teeth to find. are is it just me wishful thinking.

[Qiaozhi]

so does that make mine more of a unique crossbow and like hens teeth to find. are is it just me wishful thinking.

You should contact the person who constructed it to see how many he has produced.

[SVEN1]

There were maybe 7 who took the CrossBow challenge. Most picked up 1 or 2 PCB's each.
I believe there were 10-15 PCB's made of ver. B. and possibly the same amount of vers. C.
Vers. B had some building parts issues, there may have been 1 or 3 that worked of those completed. (GREEN PCB)
Vers. C saw better success, still think no more than 3 possibly 4 functioning units were built. (BLACK PCB)(BLUE PCB)

So any others who may have had PCB's made on their own, I don't know.

The build is rather complex for a beginner or even some one experienced but, do-able.
https://www.google.ca/search?q=cross...w=1598&bih=739

[TowySalmon]

I have seen two 'clones'/'kit" builds on ebay uk in past year and one 'original' by George Overton on ebay Germany recently, Number 3 which I bought and am thrilled to own as it is original and unique. Some people, enthusiasts would have mine in a glass case by now haha. But I am using it, enjoying it and still looking for another coil for it.
Please do not take it personally Keith, but if your 'homemade' detector works, appreciate it, cherish it and use it just like I do with an original. Yours in a way has improvements, so just enjoy it.
If you want a value of it, put it up for sale. You will get what someone is prepared to pay....and only that.
Regards,

[Qiaozhi]

The clones that were on eBay are based on a revised PCB layout (the one I supplied to Sven) so there's no need to think that they're any less good than the originals. In fact, the recent one (which I believe was purchased by keith777) appeared to be well constructed. Most people, who have made copies, have built them for their own use. There only seems to be one person who's selling clones on eBay, and that's on a very infrequent basis.

[Qiaozhi]

I've just re-discovered a document I created that describes how to connect a Minelab GPX coil to the Crossbow PI.
Might be of interest ...

[TowySalmon]

That .pdf document has made things so much clearer for me; absolutely marvelous.
Thanks so much,

[TowySalmon]

I have come down to choice between two coils, 15"x12" (905gm) or 18"x15" (1035gm) Detech SEF coils for Minelab GPX, GP and SD series. I discounted the new 15" due to the cost and weight. Which of the two above would you chose? Detech tell me that both will be ok for gold and silver jewelry on wet beaches.
I will have a go at making the adapter cable as per the details previously kindly given.

[TowySalmon]

I bought a 15"x12" Detech SEF.
I have made up an adapter cable and checked for continuity.
Connected the adapter cable and turned on the machine but something is not right. The machine makes a continuous noise, but it does not click click on threshold like with the original coil. Passing metal over the coil does not change the sound.
I am quite disappointed.
Can anyone help me please?

[keith777]

i really hope someone comes along and can help you out on this. i would really love to see that large coil working on the crossbow.
it would be cool to see it in action in a video.

[Qiaozhi]

I bought a 15"x12" Detech SEF.
I have made up an adapter cable and checked for continuity.
Connected the adapter cable and turned on the machine but something is not right. The machine makes a continuous noise, but it does not click click on threshold like with the original coil. Passing metal over the coil does not change the sound.
I am quite disappointed.
Can anyone help me please?

Can you post the wiring details of the Detech coil and your adapter cable. Then we can figure out what's wrong.

[TowySalmon]

I am sorry, but I have no idea of the wiring details. Do I undo the plug at end of cable and post a picture?
As regards the adapter, it is as per the pdf document you posted here. Three wires used. 1 to 1, 3 to 3 and 5 to 5 as per diagram. Is this correct?
The coil is for GPX, GP SD series.

[TowySalmon]

Checked adapter. Changed connections and retried. Still same. Very noisy. Connected original coil=perfect. Tried adapter again and noticed that after a while the red battery light did not go completely off, remained on, but very dim.
I think I had better wait to see if it is suggested here for me to take apart new coil cable plug.