New Project

[homefire]

How about a 20 -60 pF Variable to figure it out ?

[Prospekteur]

Is it possible to tune up the Lobo? Ive seen some lobo shematics here. Can someone post a fully working shematic (one sided pcb layout) of it? The lobo is also an option for my next project.

[homefire]

Brand new Lobo pcb 03-11-12.pdfLatest Rev.2.0 Lobo pcb keep.pdfLatest rev.2.0 Lobo component over-lay keep.pdfLa%20liste%20des%20composants(1).pdf


Tesoro Lobo Parts List
Done by Eugene January 25th 2012



RESISTORS AND QUANTITY :
All are metal film 1% tolerance 1/4 watt resistors unless otherwise stated below.
6.19 k = 2
100 k = 8
10 k = 9
22 k = 2
1 k = 7
5.1 k = 2
8.45 k = 1
49.7 k = 2
23.2 k = 3
27 k = 1
47 k = 5
200 k = 3
470 k = 1
510 k = 1
38.3 ohms = 1
825 ohms = 1
82 k = 1
68.1 ohms = 1
100 ohms = 5
14.7 k = 1
1 meg ohm = 5
2 meg ohm = 1
3.6 meg ohm = 1
20 meg ohm = 1

Capacitors

100 pf = 3
10 pf = 3
5 pf = 3
51 pf = 2
47 nf = 5
100 nf = 5
330 nf = 3
470 nf = 3
22 nf = 1
220 nf = 4
10 nf = 3
220 uf 16 volt electrolytic capacitor
10 uf 16 volt electrolytic capacitor
2.2 nf = 2
1 uf = 4
4.7 uf = 2


Integrated Circuits/Diodes/Transistors:

U4=NE5534
U6=LM392N
U1=7555
U2=4024N
U14=LM358N
U13=LF442N
U5=LM393N
U8=LM358N
U3=7660CPA
U9=LM358N
U7=NE5532A
U12=LM3393N
U10=LM308N
U11=LM308N
U15=LM2930T-8

Diodes:
1N1418 = 6

Transistors:
2N2222=1
2N2907=1
BF245=4

Potentiometers:

P1=100 k [discrimination adjust]
P2=100 k [Ground balance]
P3= 10 k [sensitivity adjust]

VR1 2.5 k [pc mount variable resistor] frequency adjust
VR2 2.5 k [pc mount variable resistor] amplitute adjust.

optional:
21.2 k 1% resistor = 3
84.5 k 1% resistor = 1

Headphone jack
12 volt rechargeable battery pack

10" x 5" Elliptical Search coil Parameters :

Tx [transmit]
1.33 m.h. @ 11 ohm dc resistance = 65 turns of .28 m.m wire

Rx [receive]
10.97 m.h. @ 50.5 dc ohms resistance = 170 turns of 0.22 m.m. wire

[Davor]

How about a 20 -60 pF Variable to figure it out ?

Can do, but it is an overkill. Simply scale them down linearly and that should do.

[Koala]

Is it possible to tune up the Lobo? Ive seen some lobo shematics here. Can someone post a fully working shematic (one sided pcb layout) of it? The lobo is also an option for my next project.

https://translate.google.co.uk/trans....ru&edit-text=


Ah link isn't working.


click

Tesoro

Then Lobos the American dream

[Davor]

Just a small disclaimer. At this point I'm not inclined to go for a LF detector, but that's simply due to the terrains I'm detecting on. LF has a great potential for very dry terrains, and small targets. Ideally for detecting nuggets in ancient riverbeds in a desert. Water response is proportional with frequency, hence more trouble, while small targets get better phase response.
There is also considerably less RF noise in LF than VLF, so it makes it interesting for 2boxx.
All things considered - I'm not exactly in need of it at the moment. But I'll take a peek here occasionally.

[Prospekteur]

Thanks homefire (thats exactly what i need), Koala (md4u.....what a great forum;-) ) and davor. I think i will build an lobo first.
But im still interested in building an high frequency Maschine. Davor....lat me know when you did invent something new about high frequency device. Im really want to build such a machine in the future;-)

[homefire]

Well the GMT running 48Khz is the cats meo here in New Mexico and Arizona on the Crumb size nuggets. Lot more Crumbs then Larger Nuggets to be had.

Eugine was working on the LoBo for quite some time. Guess he has more important things going on these days. I have a Pile of stuff on it here. Bit confusing on what is New or Rehash. I think I gave you the newest goodies. On the LoBo there are two resisters that I could never find. I was planing on making them. File notches in Carbon Resistors a little under in value of what is needed.

[chemelec]

On the LoBo there are two resisters that I could never find. I was planing on making them. File notches in Carbon Resistors a little under in value of what is needed.

What Values.

[homefire]

6.19 k = 2

68.1 ohms = 1

38.3 Ohm = 1

I know they make them , I just could not find them. Probably find those with just Tolerance Slop.

[Davor]

Don't make them, but consider the reasoning for that values. The values that are strictly in E48 tolerance range, and not in E24 or below, are the designer's way of ensuring the value will most certainly be within 2% tolerance, regardless of the supply chain. Funny thing is that shops are usually replenished with 1% resistors, but from E24 values.
All of these values are easily substituted with E24 ones.
6.19k -> 620k 1%
68.1 -> 68
38.3 -> 39

[chemelec]

I have the 6.19K resistors. Could mail you a few.
But not the others.

However, Measuring some 6.2K, 68 and 39 Ohm, 5% ones, You can probably get Close to the Values you require.

[homefire]

Thanks for the Offer Gary. I'm sure I will find them by testing a pile. Even 5% as long as they meter for what's needed.

[green]

6.19 k = 2

68.1 ohms = 1

38.3 Ohm = 1

I know they make them , I just could not find them. Probably find those with just Tolerance Slop.

Digikey lists them. Sometimes need to pick a resistor close to the listed value. I usually call for a 500 ohm resistor on the schematic but use a 499 because I can't find the 500 ohm or it is a lot more expensive.

[homefire]

Yea, most times you can just use what ever is close even in the ball park . I just like to Build As prescribed. That way if something goes sideways it wasn't me subbing parts.