Whites Surf PI schematic

[6666]

ok on the change of value to 100 pf from the original cct
I guess somebody found this value to be better
thanks

[kuraja]

I think that for Surfmaster's top performance you'd need a low resistance, low capacitance coax. cable. Preferably the one for connecting Hi Fi gear.
It is very elastic and good to use.

[chemelec]

ok on the change of value to 100 pf from the original cct
I guess somebody found this value to be better
thanks

These Capacitor Value Changes on "my circuit" are Because it is driving at a Higher Voltage, directly from the 555.

[6666]

These Capacitor Value Changes on "my circuit" are Because it is driving at a Higher Voltage, directly from the 555.

Hi
thats fine , keeping the drive voltage down
its not easy keeping up with all the mods
I have a bunch of 100pf's in the junk box

dare I ask about no damping resistor across the coil on the new cct ?

[chemelec]

Hi
thats fine , keeping the drive voltage down
its not easy keeping up with all the mods
I have a bunch of 100pf's in the junk box

dare I ask about no damping resistor across the coil on the new cct ?

I just used a 330 ohm. (It was laying on my bench.)

Like I said previously, I didn't make this up as a Completed Unit for Outside. Just some Playing around on my bench.

[6666]

Gary
I am just asking a simple question here as I am trying to learn something


In comparing the Pulse 1 cct and the new surf cct that you drew
I am little confused as to why the drain/source connections
on the fet between IC9 and IC10 on the pusle 1
and the two fets between the tl071 and LM358 on the surf are different.

The ccts look basically the same but slightly different values
on the pulse 1 the signal from IC9 comes from between the .1 cap
and 68k resister and goes to the source of the fet.

on the surf the signal comes from the TL071 from between the .1 cap and 1k resister but goes to the drain of the fets

I would have thought the signal from basically the same spot would be the same polarity in both ccts, this is a puzzle and I await your words of wisdom thanks

[6666]

question has been answered

[Virdi_248]

Complete detector. It works well except that I have two problems.

1) Review with the photolith pen, the tracks are very close to each other.

2) The detector after 15 minutes it begins to make strange noises.

3) I can not put 12V, starting a sound impossible to be silent. I have to feed 11V to operate.

Anybody can help me find out what is going on?

The detector is a copy of it.

[erolunall]

Hello
http://www.geotech1.com/forums/showt...=13810&page=12
Q6 is bc 337 & maybe reverse ,look 278. mail from Waikiki sweep
Best Wishes

Erol

[Virdi_248]

Hello
http://www.geotech1.com/forums/showt...=13810&page=12
Q6 is bc 337 & maybe reverse ,look 278. mail from Waikiki sweep
Best Wishes

Erol

Hello.

It is possible that this evil inserted q6?

Sampling metal detector image of itself

[Virdi_248]

Q6 and poorly inserted FINALLY Changed By MPSA13 Now everything correctly.

The coil is made of 190 mm internal diameter of 22 turns, 0.4 mm enamelled wire.

Spool of thread connection for a circuit and hi-fi free of oxygen.

Tests: 1 euro 26cm in air
can of soda: 50 cm

The detector has been very stable. Now to test in the field.

Thanks for the help. A greeting.

[ODM]

a low resistance, low capacitance coax. cable. Preferably the one for connecting Hi Fi gear.

A word of warning, most audio cables have a rather high capacitance. A thick coaxial antenna cable would do better, preferably with a multistrand center conductor. A flexible white TV antenna cable had surprisingly low capacitance, and it's easily available

http://www.epanorama.net/documents/w...coaxcable.html

[Virdi_248]

Hello, my sufmaster works perfect. But I have a problem, want to replace the buzzer for a headphone jack. I have this jack female.

As I can connect?

I need an amplifier or something similar?

[detectorman]

Hello!

I would like to put a low battery signal circuit in my Surfmaster PI. What is the minimum voltage when the MD works well, but the circuit must have to give a signal before the MD's accumulator discharge?
Somebody can post to me a right circuit?
Thanks and sorry for my bad english.

[chemelec]

Hello, my sufmaster works perfect. But I have a problem, want to replace the buzzer for a headphone jack. I have this jack female.

As I can connect?

I need an amplifier or something similar?

Thats a Mono Jack.
If you have Stereo Headphones, you want a Stereo Jack.