tr metal detector

[Esteban]

I also saw similar detector with two operators. It was early russian bomb detector. But now it possible to build simple and cheap device with the same parameters by using opamps. I can draw circuit that designed several years ago but I need time. It was "wet" but worked enough stable.

Maybe. But here sometimes a couple of many ICs can't replace few transistors. I think that 2 box must be "crude" type...

[Gervm]

I also saw similar detector with two operators. It was early russian bomb detector. But now it possible to build simple and cheap device with the same parameters by using opamps. I can draw circuit that designed several years ago but I need time. It was "wet" but worked enough stable.

[Esteban]

It`s more liked on usual VLF IB metal detector. With the same success you may use TR coil construction with any detector of this type. I prefer "hear what I`ve transmited". For it several reasons. Power of transmiter may be medium or low but gain of amplifire must be high and the higher the better. Also on low frequency I use signal compensator to reduce leftover signal from TR coil. I don`t see it here so I think - It will be very difficult for this detector to find auto car (large target) at distance 3-4m.

This deppend of size of the 2 box too. I've seen a 2 box with 3 mm aluminium wire in coil, transmitter push-pull BD135-136. This detector is carry by 2 persons due the weight, but depth is more than 5 meters for big objects. Now, consumption is high and "out the regulations". Excess of sensibility in receiver can be bad, causes of inestability, you must found best point.

[Gervm]

It`s more liked on usual VLF IB metal detector. With the same success you may use TR coil construction with any detector of this type. I prefer "hear what I`ve transmited". For it several reasons. Power of transmiter may be medium or low but gain of amplifire must be high and the higher the better. Also on low frequency I use signal compensator to reduce leftover signal from TR coil. I don`t see it here so I think - It will be very difficult for this detector to find auto car (large target) at distance 3-4m.

[Esteban]

YOUR OPINION ABOUT THIS CICUIT????

I respond you in other post: "Maybe somebody build it. For me, is complicated for 2 box."

[Esteban]

I built similar detectors. And my advise for who want... First of all you have to make good mechanical construction for coils. It must be hard. Even very good circuit won`t work without it.

Yes, this is true.

[mesy64]

YOUR OPINION ABOUT THIS CICUIT????

[Gervm]

I built similar detectors. And my advise for who want... First of all you have to make good mechanical construction for coils. It must be hard. Even very good circuit won`t work without it.

[Esteban]

This is a receiver with VCO. I don't build for 2 box detector, but at first sight and in workbench appears ideal for 2 box detector. This web page is in 2 parts. PCB is correct, look that pin 9 of LM380 is not connected. I build it at common MD with oval coil, but you can't use cilindrical plane cable here, only paralell shielded. This detect a mass of copper wire (not in shortcircuit). I believe strongly this is also ideal for 2 box.

http://www.detectorists.net/ibmetal.html

[Esteban]

HI ESTEBAN.
PLEASE SEE THIS LINK AN GIVE YOUR OPINION
http://www.geotech1.com/forums/showthread.php?t=16116

Maybe somebody build it. For me, is complicated for 2 box. I think 2 box is a crude detector. Power in transmitter (modulated or not) and sensitive in receiver. Much depend in the exact tune of cap. in coil receiver and correct cap. tank in transmitter coil for to transfer more energy Tx to Rx. There are regulations, but I believe that for personal use you can "abuse" in radiation of Tx.

The Charles D. Rakes 2 boxes is good with some mods. (severals). This detector doesn't use audio, only mechanical uamp. (100-200 uA).

If admin permits or he obtain permission of Charles D. Rakes, I can post here.

This is a sample what I do with Tx. First, I change silicon transistor by germanium in oscillator. Second, consumption forced 22-25 mA with replacing resistor of emmitter. Use the lowest you can, but always you're sure that oscillations starts. The limit can be 2R7, because with 2R2 don't oscillate. Independent batteries are used for Tx and Rx. 6X1.5 V alkalines for each part (Tx and Rx).

[mesy64]

Here:

http://www.geotech1.com/pages/metdet.../buccaneer.pdf

I BUILT THIS DETECTOR 8 LATER .
DETECT DEPTH IS LOW.18 CM FOR COIN .MAXIM DEPTH FOR VERY LARG TARGET IS 150 CM.
THIS DETECTOR NOT GOOD FOR OPRATION

[mesy64]

HI ESTEBAN.
PLEASE SEE THIS LINK AN GIVE YOUR OPINION

http://www.geotech1.com/forums/showthread.php?t=16116

[Esteban]

Here the dimensions.

[Esteban]

This is a 2 box in project. You have here some ideas

[mesy64]

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