10 Khz DD COIL

[jroux]

Hello, how to make a double d 27 cm coil in 10 khz frequency with 30awg, number of turns for rx and tx and how to connect the wires in the coil and a 4 pin connector, i have not frequency meter or osciloscope. I've see the post for tgsl but is in 14khz.
Best regards.

[jroux]

nobody has an idea please.

[metal mania]

The starting point for me would be the tgsl you mentioned how could you null without oscilloscope and why its a little like trying to fix a car engine without a tool set . I would have to ask why they are quite cheap best wishes

[Overtheedge]

I'm new as they come to this. I'm 1960's tech, but just gone done winding up a BFO coil 5" diameter and 156 turns for the BFO detector in ITMD (measured 5.56mH) and solidified with Q-dope. What are the inductances required for your MD. If you have no idea, how about the capacitors and their layout in the tank circuits? Colpitts, Hartley, Armstrong, etc.

Been my observation that the folks here are quick to help. They just need something to go on. Oo, oo, what is your model of MD? Bound to be someone who knows just what the required inductance is if they just knew what MD you have.
eric

[jroux]

My detector is an Armand anticus he works at the fréquency of 10khz,his coil is concentric and no so good in depht. The manufacturer tell me that i can you some coils of Tesoro who are in 10khz. I just need to know the number of turns for rx and tx to buid a double D coil in 27cm, I use 30 awg wire.For the nulling i use the method for tgsl Capacitor on pin 3 and 4 is 28,8nf , i don't have the schematic of this detector.
Many thanks for your help.

[Overtheedge]

I would suggest getting a copy of "Inside the Metal Detector." Chapter 10 has a good write-up on building a 20cm DD (designed for 10 kHz Tesoro type MDs). Combine that info with the coil calculator on this site and construction should be relatively easy.

eric

[jroux]

Ok thank you , i'll try , but the coil calculator doesn't work in windows seven

[dfbowers]

Ok thank you , i'll try , but the coil calculator doesn't work in windows seven

The coil calculator runs fine in Windows 7. It might be your browser (I'm running IE Version eight) or maybe you do not have ActiveX installed or enabled.

[Qiaozhi]

Ok thank you , i'll try , but the coil calculator doesn't work in windows seven

The coil calculator will run in any browser that supports JavaScript, which is virtually all of them. This makes it platform independent.
http://support.microsoft.com/gp/howtoscript

[jroux]

Sorry i run it with Firefox and active x is disabled.
Thanks.

[jroux]

Something wrongs on the calculator , when i test values of the tgsl coil building from Silverdog, with his values :inner radius 137, wire thickness 0.25, number of turns 107 , the coil calculator give me these results : mean radius 138,29, coil thickness 2,59, inductance 9,674.
But the inductance may be 6.5 mh ,it's write in the pdf , where is the error ?

[jroux]

My problem is simple , i've inner radius 137mm, wire 0.25mm, i need final frequency of the coil 10khz.Correct me if I'm wrong: for TX :81 tourns, for RX:87 tourns that done tx =5.75mh and rx 6.2 mh.

[Jabberwock]

you don't have the good input data to make your coil. frequency depends on the inductance and capacitor value on the oscillator. the coil made for TGSL. at 14khz will oscillate at 10khz on a deleon. my deleon works with the tgsl coil I built and the tgsl works with the deleon spider coil.
To be sure it will be ok, you need to check resistance and indutance of the original coil.
Btw, tgsl coil needs 102 and 110 turns for me "in real life"

Cheap LC meter is available from ebay or others to check inductance

[jroux]

Thanks i understand now, i've just a simple mutimeter.

[Jabberwock]

You can just build the coil from the tgsl101 file. It should work if resistance of your coils is around 25 ohm