I need Information about Heathkit Groundtrack1290

[diminute]

I need information to construct a coil to this detector.

Shape and coils, gauge, turns, etc.

Thanks.

diminute

[diminute]

Nobody ???

Nobody know anything about that ????

Thanks


diminute

[diminute]

please

answer,

please.

[Qiaozhi]

I need information to construct a coil to this detector.

Shape and coils, gauge, turns, etc.

Thanks.

diminute

Looking at the schematic for the 1290, it shouldn't be too difficult to figure out the TX and RX inductance values, using the frequency given (7.3KHz) and the capacitance values.

[diminute]

I don't know

I don't know anything about that.

Only the frecuency.

May be somebody here has that datas.

Thanks,

diminute

[diminute]

Sorry

Help me !!!

I know that ETI 1500 use a coil like this.

Thanks, again

diminute.

[Qiaozhi]

Help me !!!

I know that ETI 1500 use a coil like this.

Thanks, again

diminute.

It looks like the ETI 1500 uses a coplanar coil, but I always thought the Heathkit designs used an omega coil.
I'll see if it's possible to figure out the coil details. Just give me a few days, as I'm going to be out of action for the rest of this week.

[Mrand]

I constructed this detector over 25 years back. I looked the archive and I found parameters of the search head. The original probe has the diameter around 15cm, my coil was 30cm. See this link.
http://www.proscan.gliwice.pl/vlftr1.gif
When L1 = 300mm and L2 = 140mm and L3 = 130mm then
L1,L2 have 90 turns 0.4mm wire and L3 have 550 turns 0.1mm wire.
Mrand

[Qiaozhi]

I constructed this detector over 25 years back. I looked the archive and I found parameters of the search head. The original probe has the diameter around 15cm, my coil was 30cm. See this link.
http://www.proscan.gliwice.pl/vlftr1.gif
When L1 = 300mm and L2 = 140mm and L3 = 130mm then
L1,L2 have 90 turns 0.4mm wire and L3 have 550 turns 0.1mm wire.
Mrand

Something doesn't seem quite correct here.
If I put these values into the Coil Calculator I get:
L1 = 6.4mH, L2 = 2.5mH and L3 = 81.27mH.

BUT - simulating the TX circuit using these values gives a frequency of 7kHz and not 7.3kHz. In practice I know that the Coil Calculator usually under estimates the inductance, and once you've tightened the windings the inductance is slightly higher than expected. Therefore it is safe to assume that the actual frequency will be even lower.

The TX is a Colpitts oscillator, but the addition of C12 complicates the hand calculations, so I used the simulator to determine that the total TX inductance needs to be 8.4mH, as opposed to L1 + L2 = 8.93mH.

The RX inductance is somewhat easier to ascertain. With an RX inductance of 4700pF and a frequency of 7.3kHz, the inductance should be 101.1mH. The Coil Calculator gave 81.27mH using the given winding data, which means the receiver is tuned to 8.14kHz. This may of course be correct, and could be necessary to achieve correct phasing of the coils.

Personally I would suggest using the coil data supplied by Mrand, but then adjust the value of C12 to get the correct TX frequency. Simulation shows that 220nF would be a good value.

Please keep us informed on your progress with this project, and good luck!

[diminute]

OK, good news

I believe that with these datas everythings will be fine.

But if you have the original values, please put its here.

Thanks,

diminute

[Eugene52]

Here are two schematics :

Here are two pdf schematics , for the Geotech archives that got erased last month :

I also found in perfect condition over 100 Geotech "pdf metal detector patents" I downloaded last year , If any one needs them again !! Let me know . But I do not think they can be downloaded at once !!
Eugene52

[diminute]

Coil

Thanks Eugene,

I have problem with the coil construction for this MD. I don't how make it.

Thanks again,

diminute

[Eugene52]

Heathkits

Thanks Eugene,

I have problem with the coil construction for this MD. I don't how make it.

Thanks again,

diminute

Hello Diminite , I owned a few heathkit Metal detectors in my life , I should have kept em . They are old antiques , like me !!

I think the search coil is 6 inch diameter for both the cointrack and groundtrack . These coils were made at the heathkit factory , and came with the heathkit project . I think there is enough information on the schematic , and using some inductance calculation formulas . You should be able to wind an inductance-balance search coil . Experiment a little , because a Dime at 6 inches was the depth of those machines !!

If I find out more , I will post later . Or someone else will post If I am wrong about something

Heathkits were a lot of fun , Years Ago , I would love to see them come back again !!!!!!!

Regards............Eugene52

[diminute]

A big "Thanks"

I believe that with this information I have a basics to try to make my first GT1290 coil.

Again I give you a big "Thanks".

Regards,

diminute

[vujkozuno]

Here are two pdf schematics , for the Geotech archives that got erased last month :

I also found in perfect condition over 100 Geotech "pdf metal detector patents" I downloaded last year , If any one needs them again !! Let me know . But I do not think they can be downloaded at once !!
Eugene52

Hi Eugene32,

Im interested in those 100 Geotech pdf metal detector patents. Could you please tell my how can we contact (ex. email) to send me these pdfs.

Best regards,
vujkozuno