The Crossbow Classic PI

[Qiaozhi]

Qiaozhi, I am awaiting delivery of a recently bought Crossbow. It is one of the originals.
Is it please possible for you to provide me with a user manual? Or could anyone kindly direct me to where I may download one from.

Can anyone help with suggestions of compatible coils please? I have read somewhere that the following can be used:
Detech 18” Mono
14”x10” brand not known

Thank you.
PS, I am unable to send PMs as access is denied when I click on someones name. E.g I tried to PM Qiaozhi but failed.

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.

Hi TowySalmon

here is the instructions that i got with my Crossbow Classic PI.

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/

[TowySalmon]

Gentlemen, what a lovely surprise on a wet and dreary Saturday morning.
Thanks you both for your kind efforts. I will have a read with my second cup of coffee.
Qiaozhi, the coil info’ is much appreciated.

[SVEN1]

Please note my forum is a closed forum only for those that had purchased a Mirage PCB in the past. The Crossbow sub-forum is part of the Mirage Forum set up for 12 or so of us who were building/experimenting the CrossBow.
For the most part the CrossBow sub-forum has been inactive for the past year or so.
2 maybe 3 members were successful building the CB but, there were issues and challenges with both revision B and C.
Rev. C was the last George sent us. I did not complete mine as I was too busy with the Mirage Pi project.

The files below would help anyone attempting the build.
We attempted to make a pdf. building instruction file, we were up to page 9, not completed but, helpful.
CROSSBOW GERBER FILES.zip
Crossbow Classic PI - Schematic.pdf
CROSSBOW PARTS LIST.pdf
Minelab_GPX_Coil.pdf

Crossbow Controls.pdf
Crossbow Build Directions.pdf


Added Info from George:

The original Crossbow coils have the damping resistor in the coil shell,but you can put the resistor inside the enclosure, on the back of the
coil connector, if you would prefer.
Here is the calibration procedure that I used:
1. Power the detector from a bench power supply set to 10.5V. Adjust R42
so that the Battery Low LED just turns on.
2. Connect battery pack.
3. Adjust the TX frequency to 1kHz (1000pps)
4. Adjust the TX pulse width to give 200mA quiescent current consumption
(with coil connected). The pulse width should then be approximately
120us.
5. Disconnect coil and set voltage at preamp output to 0V by adjusting
R28.
6. Set Sensitivity pot (R6) to mid-position.
7. Set minimum delay setting (R1 to 25us. You may be able to set this
to a lower value, depending on the coil.
8. Set secondary sample pulse (R19) to 400us.
Kind Regards
George
R24 is a 3R3 value resistor that is placed in series with the coil to
limit the maximum current. The idea here is to get the current to level
out so that it's not changing rapidly in the opposite direction when the
MOSFET switches off.
The original Crossbow uses a 5-pin connector for the coil, and pins 1, 2
and 3 of PL3, go to pins 1, 5 and 3 respectively of the coil connector.
Then, for a mono coil, pins 1 and 5 are shorted together inside the coil
plug. This will give you the flexibility of also using an IB coil if you
desire. When using commercial coils (that do not have a resistor in the
coil shell) with the Crossbow, you can place a 470R damping resistor
across pins 2 and 4, and wire the mono coil plug so that pins 1, 5 and 2
are shorted together, and likewise for pins 3 and 4. If the damping
resistor needs to be a lower value than 470R, you can then fit a
suitable high value resistor (low wattage) resistor inside the coil
plug.

[SVEN1]

[Qiaozhi]

Thanks Sven.

Both the Mirage PI and Crossbow Classic are Hammerhead variants.
The MPI is intended for finding small low conductivity targets, and the CCPI is designed for beach and hoard detecting.

[keith777]

whats the biggest coil out there that has been used on the crossbow.

[Qiaozhi]

whats the biggest coil out there that has been used on the crossbow.

There's a video on youtube showing the CCPI with an 18" diameter Detech coil. That's the largest I know about.

[keith777]

There's a video on youtube showing the CCPI with an 18" diameter Detech coil. That's the largest I know about.

do you have a link for the video.......

[Qiaozhi]

do you have a link for the video.......

You can find a few videos of the CCPI by searching for "crossbow classic pi metal detector" in youtube. The 18" coil video is a bit disappointing, as it doesn't even show the coil.
There used to be a good video of someone using a CCPI on a beach in Ireland, but it seems to have vanished.

[TowySalmon]

The Crossbow arrived yesterday and I spent a few hours mounting the control box on a straight length of carbon fibre at the top end. The top 4” had been strengthened with car body filler with added fibres prior to drilling for the two bolts. Below this I put an arm cuff (not the one that came with machine) and below this a handle. I used the original middle and bottom section of the shaft. It balances wonderfully.

I spent 3 hours on the beach with it today. I kept thinking of how teeny the coil looked (I have used a 15” coil on another detector for past 9 years almost exclusively). I have used PIs in the past and I soon got into using the Crossbow.

Please excuse my lack of knowledge but I do have some thoughts and questions and I would be grateful for any comments and/or suggestions in return.

I feel that I need to be using a bigger coil in order to cover more ground. I think that this would be a DD coil as less overlapping in the sweep is required compared to a mono coil(?).

I did look at Minelabs specification charts of coils. What struck me about the mono coils was that they are water resistant and not waterproof; so they’re not to be considered.

If I do consider a mono coil, do I check that it has a specification of: Inductance 500uH and Resistance 2ohms with a built in damping resistor? I guess that the connections inside its 5 pin connector (if it has one of 5 pin) will have to be altered as per previous info’ provided by George?

I have seen drawings comparing the signal shape in the ground between the two types of coil, will the shape remain the same with a DD coil on a PI machine? I note that DD coils seem to be made for individual detectors, e.g. a coil for a Minelab Sovereign wont work on a Minelab Explorer. So how do I find a DD coil for the Crossbow? What specifications do I need to find or ask a manufacturer for? Will the 5 pin connector connections need to be altered?

I appreciate that DD coil may not be as deep as the same size of mono coil, but I just have a gut feeling that I would be happier with say a 15” to 18” DD, oh and round, not ellipse.

Sorry for the lengthy post.
I am thrilled though to be a very proud owner of this machine. I want to get the best out of it for me. I am hoping it will give me years of enjoyment.

Oh, almost forgot….How do I tell when it is fully charged?
Thank you.

[homefire]

""Oh, almost forgot….How do I tell when it is fully charged?""

What kind of batteries are they ?

[TowySalmon]

12 x rechargeable(white in colour) Eneloop AA, but I didn't look to see what mAh they are.

[keith777]

this was my crossbow before i put it on to a straight shaft.

[kt315]

unreadable pics K777.

[homefire]

NiCad should be charged when they are up to or just over the rated 1.2V and pulling less then the C-10 Rate. 1/10th the Capacity Rating.

Same with NiMH

Li Ion charged on Reaching 4.2 Volts.