Early 1934 PI?

[Esteban]

Today I post on Eric Foster's PI Tech Forum:

http://www.findmall.com/read.php?34,...472#msg-475472

Magazine: Modern Mechanix, October 1934.

blog.modernmechanix.com/2006/09/05/

[Geo]

I can't believe it !!!!!!!!!!

[Max]

Today I post on Eric Foster's PI Tech Forum:

http://www.findmall.com/read.php?34,...472#msg-475472

Magazine: Modern Mechanix, October 1934.

blog.modernmechanix.com/2006/09/05/

Hi Esteban,
could be interesting to understand if these "impulses" are what we are thinking about or just a journalist mistake (maybe the unit was continuos wave and only advertised wrong or misunderstud by the juornalist).
If instead it's a real prehistoric PI could be interesting to read the full article and understand how the impulses were made (e.g. with a relay switch) and how the rx stage worked.

Another question is about patents...or maybe, well, best intellectual proprerty issues here...because if someone else discovered PI in 30's some at least book must be revised.

I think that stuff maybe had a etherodyne stage corverter (Armstrong type) because seems that a real PI was difficault to realize with early thermoionic valves at that time.

Have you the full article ?

Best regards,
Max

[Max]

Today I post on Eric Foster's PI Tech Forum:

http://www.findmall.com/read.php?34,...472#msg-475472

Magazine: Modern Mechanix, October 1934.

blog.modernmechanix.com/2006/09/05/

Hi Esteban,
could be interesting to understand if these "impulses" are what we are thinking about or just a journalist mistake (maybe the unit was continuos wave and only advertised wrong or misunderstud by the juornalist).
If instead it's a real prehistoric PI could be interesting to read the full article and understand how the impulses were made (e.g. with a relay switch) and how the rx stage worked.

Another question is about patents...or maybe, well, best intellectual proprerty issues here...because if someone else discovered PI in 30's some at least book must be revised.

I think that stuff maybe had a etherodyne stage corverter (Armstrong type) because seems that a real PI was difficault to realize with early thermoionic valves at that time.

Have you the full article ?

Best regards,
Max

[Qiaozhi]

An interesting use for a metal detector:

Metal Detector Diagnoses Cows (Sep, 1950)
http://blog.modernmechanix.com/index...metal+detector

[Esteban]

Hi Geo, hi Max

No, don't have the complete article. Hope is not a complicated schematic because the article refers low weight, coil, battery, etc., but if the detector is a BFO type with tubes the weight is most heavy, don't know the principle, but almost sure the impulses are created by electromechanical vibrator or buzzer, operates 100-120 Hz.

I know there are many projects of enthusiast people in the world disperses in books and magazines, for example the detector published in Science & Invention in August 1921, with vibrator (called buzzer). Actuates as a rare type impulse with two coils.

As this, there are more and more. This is the reason I said: whe're reinventing the wheel and rediscovering the fire.

In the pic, the man has in the hand a pushbutton for to put in operation. The consumption in good adjustment point is near 2 A! And this is not balance/induction type, hope is two coils PI balanced by rheostat. The detector consist in:

2 exploring coils
Rheostat
Inductors
Transformer: 2 primaries, 1 secondary
Ammeter
Switch
Telephones (high Z)
Buzzer
Batteries
Pushbutton

No tubes, no heavy weight, etc.

Time by time this kind of publication I found on ebay or Abebooks.com

More temerary? Maybe near 1840 was discovered a detector like PI, but the investigator only refers the disturbance cause by metal near the coil.

[Esteban]

In the same page weapon detector:

[Geo]

Hi Geo, hi Max

This is the reason I said: whe're reinventing the wheel and rediscovering the fire.

Hi Esteban. yes you have RIGHT. The only that we do is that we make detectors with new components but with very old technique. Let's try a litle more before we let them. Ohh my God, i forgot. We must learn the old technique first (aggrrrr) .

[Esteban]

Hi Geo

And the most of the time many circuitry mean many inestabilities, many capability for to "detect" interferences, etc., but is part of the business to sell components!

[Geo]

They make their job. We what we make ??

[Esteban]

A law of Murphy said: The density of the components in a system is in direct proportion to the failure.

[Leto]

Party breaker

>>ELECTIRICAL IMPULSES<< (circa 1934) = sinusoidal waves

[proscan]

Hello,

The "PI " concept is based on the delayed sampling (time domain technique) rather than shape of the waveform that excites the coil.

To my knowledge it was Claus Colani who invented, publicised and patented PI detectors:

• A new type of locating device, Archaeometry 1966,

• Method and Apparatus for Investigating a Generally homogeneous Medium, USA patent 3315155, 1967

and

• A novel metal detector using a pulse procedure for large areas with electronic object analysis and detection, Frequenz, 1968

The latter I have scanned. I can send to anyone interested, but it is in German !!



proscan

[Chris2]

Hi Proscan,

kindly send me a copy of the German patent to my email. Thanks

Chris

[Max]

Hello,

The "PI " concept is based on the delayed sampling (time domain technique) rather than shape of the waveform that excites the coil.

To my knowledge it was Claus Colani who invented, publicised and patented PI detectors:

• A new type of locating device, Archaeometry 1966,

• Method and Apparatus for Investigating a Generally homogeneous Medium, USA patent 3315155, 1967

and

• A novel metal detector using a pulse procedure for large areas with electronic object analysis and detection, Frequenz, 1968

The latter I have scanned. I can send to anyone interested, but it is in German !!



proscan

Hi proscan,
yes, also in the Corbyn's article (end of part 2 if I remember well) there are references to Colani, and also Aitken (right ?) for the use of a PI detector in archeological surveys.

"
The "PI " concept is based on the delayed sampling (time domain technique) rather than shape of the waveform that excites the coil."

Yes but Esteban found something different - seems not CW operation so is more similar to what we mean for pulse induction : a train of pulses generated by a vibrator/buzzer.

Best regards,
Max