Voodoo Main Discussion

[MartyJ1963]

Hi Alec,,,I have a plastic enclosure that I may use but I haven't fully decided on whether to use it or not yet. I posted a pic of it with the dimensions. It is 50mm deep but if I decide to use it I may cut the top off it to make it around 35mm deep or so that there's just a bit of clearance on the tallest components. The lid fits snuggly over the bottom part. I don't intend including the Battery charge board and battery in the same enclosure as I want to be able to use 18650 batteries and change them as they deplete in the field. This enclosure is only a 'Maybe' at the moment. The handle is going to be made in 2 parts with a hollow centre to accept the LCD/Menu button cable and will join to the top part of the enclosure that will slide directly over the detector shaft. I have some other ideas so I won't know which enclosure I will decide on until I reach the LCD Section of the build. I'm enjoying your 'HammerHead' build videos!,,Do you have the Gerber files for that particular pcb you're building on the Video? With the Mirage being my favourite detector I've always wanted to tackle the HammerHead and the Crossbow to add to my collection. Stay safe Alec, Regards, Marty.

[lamoiz]

George, have you tried hybrid mode on the wet sands of the beach?

[Qiaozhi]

I don't intend including the Battery charge board and battery in the same enclosure ...

The battery charger not intended to fit in the detector enclosure. It is an external unit.

[Qiaozhi]

George, have you tried hybrid mode on the wet sands of the beach?

I had intended to do that, but I live a long way from the nearest beach and Covid restrictions prevented me from going there. However, the PI mode will definitely work in the wet sands. Since an audio response depends on both the PI and DISC channels responding at the same time, I have every confidence that there won't be a problem. Remember that false signals from a VLF detector in wet sand are caused by the GEB channel, not the DISC channel.

[MartyJ1963]

Thanks George,,,Sorry, About the Battery charger pcb, I'd realised what I'd written only after I wrote it,,I meant just to say I didn't want the batteries in the enclosure,,my bad,,Lol. I wanted to start the power supply section 2 nights ago but some repairs we've been doing to do the house were overlooked so I'll be startng tomorrow now. Just curious, but could a circular dual field TX coil be used with the RX? And if so, would the Dual field coil ( like a spider coil) still need two damping resistors? Thanks, Regards, Marty.

[Qiaozhi]

Just curious, but could a circular dual field TX coil be used with the RX? And if so, would the Dual field coil ( like a spider coil) still need two damping resistors? Thanks, Regards, Marty.

I don't think you could have a dual-field coil that has a concentric RX loop. At least I've never seen one.

[MartyJ1963]

Hi George, I forgot to ask you in my last post,,What would be the best cable to use for this coil setup please? Thanks, Marty.

[6666]

Here is a slight variation on the concentric coil it has a small loop for fine tuning the null.

[zakari]

hi 6666
i am thinking you must connect the end of the red wire to starting of the blue wire not the green.
in this case that is difficult to nulling the concentric coil and you cant add or reduce laps the green wire for best inductance and best nulling .

best regard
zakari

[surfdetector]

hi 6666
i am thinking you must connect the end of the red wire to starting of the blue wire not the green.
in this case that is difficult to nulling the concentric coil and you cant add or reduce laps the green wire for best inductance and best nulling .

best regard
zakari

I think that in the picture the Green bucking coil is actually sitting on top of the Blue RX coil. If so, that enables you to adjust the Green bucking coil, which makes the connections shown to be correct.

[6666]

I think that in the picture the Green bucking coil is actually sitting on top of the Blue RX coil. If so, that enables you to adjust the Green bucking coil, which makes the connections shown to be correct.

correct,

[lamoiz]

I had intended to do that, but I live a long way from the nearest beach and Covid restrictions prevented me from going there. However, the PI mode will definitely work in the wet sands. Since an audio response depends on both the PI and DISC channels responding at the same time, I have every confidence that there won't be a problem. Remember that false signals from a VLF detector in wet sand are caused by the GEB channel, not the DISC channel.

thanks George,
certainly in PI mode no problem, I hope to be able to test the "hybrid" mode. we too in France are confined, and it really takes a long time. it gives me time to finish this system .. and to do it very well ..

[MartyJ1963]

Thanks for the Dual field coil answer George. What's the best cable I can purchase for the Voodoos Coil setup please? Thanks, Marty.

[lamoiz]

Thanks for the Dual field coil answer George. What's the best cable I can purchase for the Voodoos Coil setup please? Thanks, Marty.

2 * RG58 ..no ??

[Qiaozhi]

Thanks for the Dual field coil answer George. What's the best cable I can purchase for the Voodoos Coil setup please? Thanks, Marty.

You could use two separate single-core RG58 screened cables (as suggested by lamoiz) or a twin-core screened cable. I've successfully used E648E twin-core noiseless microphone cable.