tr metal detector

[mesy64]

dear esteban tank you
esteba if for you possible discribtion about coils and ways build please.
i have a few problem in build coils

[Geo]

In some cases the lenght of the wand is important, this is better near 90 cm to 1 m. But if your TX power is poor, yo do nothing with 2 box. Other consideration is the type of transistor in transmitter. I use germanium type and forces the consumption to 25 mA.

Hi Esteban.
I remember a project that i made many years ago. It had a bridge with 4 transistors at the output of Tx and 2 MC1349 with 120 db gain on the receiver. Very very strong 2 Box. But, and after very fine coil calibration, i had not the ability to give full power or full Rx gain from the MC1349. With any combination, best results was near to GeminiIII. This is the reason that i say that it is very difficult to go deeper from a Gemini or a Whites with every 2Box detector. Only if you use a very large handle (2m or more) so at fine calibration you can give more power until you hear the beep


Regards

[detectoman]

hola muchachos, may be yours can give most power to two box, whit coil most large, too put the condenser of tx tubular big how olds, these amount the output, too sistem 555 to output of rx, too add other condenser, in serie or parallel, in rx coil
i solve this problem whit big tubular cap, in tx, amount 4 mts in air try

[Esteban]

There are a IB metal detector with VCO, I try rapidly in workbench as 2 boxes and can be useful. I'll search for schematic and post here.

[Geo]

Also you can use Buccaneer with very good results!!!

[Esteban]

Also you can use Buccaneer with very good results!!!

Here:

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

[mesy64]

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[Esteban]

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

[Esteban]

Here the dimensions.

[mesy64]

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

[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

[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).

[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

[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.

[mesy64]

YOUR OPINION ABOUT THIS CICUIT????