The Crossbow Classic PI

[surfdetector]

salam i from indonesia My nam ade . please send me about information PI crossbos thank so much i try to built crossbow clasic
my email [email protected]
thank so much my friend

See Post #18

[6666]

1. Here is the original User manual (attached).
2. Garrett SeaHunter MkII mono coils work very well with the Crossbow. I've tried both the 14"x10" and the 8". You will have to change the coil connector to suit.
3. Any other mono coil should also work, such those from Minelab and White's Electronics.
4. The forum does not allow you to send PMs, or to attach files, until you've made at least one post in the forum.

The instructions you have posted are for Crossbow clone, not the original.

You can find more information on Sven's PI Forum at -> https://www.tapatalk.com/groups/area51pi/

Hi Sven what happened to your forum ?

[MartyJ1963]

@6666,,,Sven closed it down over a year ago,,I think through the lack of people using it or because there weren't many people building. I was building my 2nd Mirage and I had misplaced some some build info and tried logging in to re-download what I needed but couldn't. contacted Sven and he told me he had closed the site. Hope you and your wife had a good Christmas together and I hope she's recovering well, Regards, Marty.

[6666]

@6666,,,Sven closed it down over a year ago,,I think through the lack of people using it or because there weren't many people building. I was building my 2nd Mirage and I had misplaced some some build info and tried logging in to re-download what I needed but couldn't. contacted Sven and he told me he had closed the site. Hope you and your wife had a good Christmas together and I hope she's recovering well, Regards, Marty.

Hi Marty, thanks reply, pity it closed down there was some good reference material in there. Yes we had a good Xmas thanks, hope you did to, the missus is battling on with still more tests.

[MartyJ1963]

Hi 6666,,,Yes its a shame about that site,,I logged in everyday just like I do on here,,tons of info and great reference. Hope the tests results are satifying and best wishes for you both. Regards, Marty.

[surfdetector]

Hi Marty,
Did you ever do one of the Crossbow machines or just the Mirage? I was thinking about getting a few Crossbow boards made as the Gerber files are here.
Cheers

[MartyJ1963]

Hi Alec,,,I haven't built a Crossbow yet,,It's on my 'To build' list as is the HammerHead so I can complete my collection of all the Hammerhead variants. I have all the Crossbow gerbers and I intend ordering some boards in the future. It's the Hammerhead I'm stuck with as I'm unsure which version to make. The Mirage is my favourite up till now,,I've built 8 units so far and 2 for my friends. Funny thing is I've only ever been out detecting about 4-5 times as I don't drve and the nearest beach is 2 hours away,,lol,,so I just keep building!,,lol,,Thanks, Marty

[SVEN1]

Closed down the Mirage/Crossbow forum as there was really no activity for a couple years or so. So I posted the particulars here about the CrossBow.
Regarding the Mirage, my last version I was happy with and did not need to go any further with it. Elliot took over and made up his version(s) of the Mirage with
further improvements, contact him for a PCB etc.

[surfdetector]

It turns out that the Detech SEF coil is rather unusual. Initially it was assumed that the coil was a DD type, which was quite reasonable as Detech advertise it as such. However, the cover of the box says:
-----------------------------------------------------------------------------
The double elliptical coil with Symmetric Electro-magnetic Field
is the best performance coil.
Compared to the Double D coils it has the following advantages:
- better ground balance
- more stable operation
- deeper in the ground
- better pinpointing
- more accurate target identification
-----------------------------------------------------------------------------
So clearly it's not a DD coil after all.

The coil plug wiring is as follows:
L1 263uH (6R6) coil between pins 1 and 2
L2 706uH (7R0) between pins 2 and 3
pins 1 and 5 connected together
pins 3 and 4 connected together

Obviously, with pins 1 and 5 shorted together, the coil plug wiring is connecting the coil as a mono with L1 and L2 in series. Effectively this means the detector "sees" a mono coil with 439uH, requiring a 330R damping resistor between pins 4 and 5.
What's interesting is that a mono coil is sensitive from edge to edge, whereas the SEF coil is sensitive across the overlapping section of the two loops. Hence it reacts like a DD coil, but with the advantages of a mono.

In a way, this setup is similar to a White's Dual Field, but in a Butterfly (DD) format. Although, in this case, it was possible to critically damp the coil with one resistor.

@Qiaozhi Would this coil require nulling prior to having the series connections made?

[Qiaozhi]

@Qiaozhi Would this coil require nulling prior to having the series connections made?

I was examining this coil for someone else who wanted to use it on a Crossbow detector. That post was from Nov 2017, and I cannot remember whether the two loops were balanced, although I suspect not.
It would be interesting to experiment with this configuration.

[6666]

I was examining this coil for someone else who wanted to use it on a Crossbow detector. That post was from Nov 2017, and I cannot remember whether the two loops were balanced, although I suspect not.
It would be interesting to experiment with this configuration.

Was there a patent number on the coil ? thanks.

[surfdetector]

I was examining this coil for someone else who wanted to use it on a Crossbow detector. That post was from Nov 2017, and I cannot remember whether the two loops were balanced, although I suspect not.
It would be interesting to experiment with this configuration.

Yes, I am wont to resurrecting old threads. I believe this one looks like a good project.

[surfdetector]

Was there a patent number on the coil ? thanks.

Yes, we need the patent number indeed,

Does this look like the correct one?
https://patentimages.storage.googlea...17015730A1.pdf

[Qiaozhi]

Yes, we need the patent number indeed,

Does this look like the correct one?
https://patentimages.storage.googlea...17015730A1.pdf

That looks like the correct patent, but I notice it mentions TX and RX coils.
If I remember correctly, the one I looked at was wired for use as a mono with both loops in series and anti-phase.
It was very strange because it still reacted as if it was a DD with the sensitive part in the crossover area between the two loops..

[6666]

Yes, we need the patent number indeed,

Does this look like the correct one?
https://patentimages.storage.googlea...17015730A1.pdf

Thanks for finding it.