On Sat, 16 Sep 2023 05:22:45 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Fri, 15 Sep 2023 13:51:44 -0700) it happened John Larkin ><jjlarkin@highlandtechnology.com> wrote in ><7ig9gi5lvb8ho1p4onrtbed451a1ftrmfn@4ax.com>: > >>On Fri, 15 Sep 2023 16:03:44 -0400 (EDT), Martin Rid >><martin_riddle@verison.net> wrote: >> >>>John Larkin <jjlarkin@highlandtechnology.com> Wrote in message:r >>>> On Fri, 15 Sep 2023 12:21:22 -0400 (EDT), Martin Rid<martin_riddle@verison.net> wrote:>Bartolomeo Pestalozzi >>>> <bartolomeopestalozzi65@gmail.com> Wrote in> message:r>> Il giorno venerd� 15 settembre 2023 alle 15:01:44 UTC+2 John Larkin ha scritto:> On >>>> Fri, 15 Sep 2023 04:57:06 -0700 (PDT), Bartolomeo Pestalozzi > <bartolomeop...@gmail.com> wrote: > > >Hello, > >I am looking for an >>>> electric schematic of a telephonic Tone and Probe. > > > >Professional instrumet are like this: > >>>> >https://www.fluke.com/en-us/product/network-cable-testers/copper/pro3000f60-kit > >I don't have the pretension nor the ambition to make a similar project. > >>>> >I would like to build a simple object to identify the stremity wires. > > > > > > > >Thank you > >Umberto> Amazon has wire >>>> tracer kits for around $16. I got one and it's > interesting. You can hear all sorts of e-fields.My purpose was to design one, >>>> anyway thanks for the indication.>>You can drive a reversed biased diode with a 555 running s a> frequency >>>in the audio band. This will create a nice broad> spectrum modulated hash.>Then use a lm386 audio amp a nd attach the input to >>>a short> antenna probe as the reciever.>I used this setup for many years, and it always works.>>Cheers>CheersThe probe should be >>>very high impedance. Use a jfet or a cmos opampand a lot of resistance to ground. >>> >>>Oh, just a cap to the probe tip. The lm386 has 28db of gain. If >>> it squeals when you touch the probe tip you got gain. >>> >>> >>>Cheers >> >>Yikes. LM386 is an ancient bipolar part with < 50K input impedance. >>Given, say, a 5 pF antenna/probe, the highpass corner frequency is >>about 300 KHz. >> > >I still have some, chip is OK, and still available I think. > https://hackerstore.nl/Artikel/310 > say 4 USD for the complete amp, inlcuding volume knob!The 10K pot makes the input impeance even lower, even worse as an e-field probe.
telephonic Tone and Probe schematic
Started by ●September 15, 2023
Reply by ●September 16, 20232023-09-16
Reply by ●September 16, 20232023-09-16
On a sunny day (Sat, 16 Sep 2023 04:52:06 -0700) it happened John Larkin <jjlarkin@highlandtechnology.com> wrote in <rj5bgitnmcvc1n3iu1nfgtufko7djs77rb@4ax.com>:>On Sat, 16 Sep 2023 05:22:45 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>On a sunny day (Fri, 15 Sep 2023 13:51:44 -0700) it happened John Larkin >><jjlarkin@highlandtechnology.com> wrote in >><7ig9gi5lvb8ho1p4onrtbed451a1ftrmfn@4ax.com>: >> >>>On Fri, 15 Sep 2023 16:03:44 -0400 (EDT), Martin Rid >>><martin_riddle@verison.net> wrote: >>> >>>>John Larkin <jjlarkin@highlandtechnology.com> Wrote in message:r >>>>> On Fri, 15 Sep 2023 12:21:22 -0400 (EDT), Martin Rid<martin_riddle@verison.net> wrote:>Bartolomeo Pestalozzi >>>>> <bartolomeopestalozzi65@gmail.com> Wrote in> message:r>> Il giorno venerd� 15 settembre 2023 alle 15:01:44 UTC+2 John >>>>> Larkin ha scritto:> On >>>>> Fri, 15 Sep 2023 04:57:06 -0700 (PDT), Bartolomeo Pestalozzi > <bartolomeop...@gmail.com> wrote: > > >Hello, > >I am >>>>> looking for an >>>>> electric schematic of a telephonic Tone and Probe. > > > >Professional instrumet are like this: > >>>>> >https://www.fluke.com/en-us/product/network-cable-testers/copper/pro3000f60-kit > >I don't have the pretension nor the >>>>> >ambition to make a similar project. > >>>>> >I would like to build a simple object to identify the stremity wires. > > > > > > > >Thank you > >Umberto> Amazon has >>>>> >wire >>>>> tracer kits for around $16. I got one and it's > interesting. You can hear all sorts of e-fields.My purpose was to design >>>>> one, >>>>> anyway thanks for the indication.>>You can drive a reversed biased diode with a 555 running s a> frequency >>>>in the audio band. This will create a nice broad> spectrum modulated hash.>Then use a lm386 audio amp a nd attach the input >>>>to >>>>a short> antenna probe as the reciever.>I used this setup for many years, and it always works.>>Cheers>CheersThe probe should >>>>be >>>>very high impedance. Use a jfet or a cmos opampand a lot of resistance to ground. >>>> >>>>Oh, just a cap to the probe tip. The lm386 has 28db of gain. If >>>> it squeals when you touch the probe tip you got gain. >>>> >>>> >>>>Cheers >>> >>>Yikes. LM386 is an ancient bipolar part with < 50K input impedance. >>>Given, say, a 5 pF antenna/probe, the highpass corner frequency is >>>about 300 KHz. >>> >> >>I still have some, chip is OK, and still available I think. >> https://hackerstore.nl/Artikel/310 >> say 4 USD for the complete amp, inlcuding volume knob! > >The 10K pot makes the input impeance even lower, even worse as an >e-field probe.You could always add a JFET or MOSFET, few more cents.
Reply by ●September 16, 20232023-09-16
On Friday, September 15, 2023 at 3:30:34 PM UTC-4, John Larkin wrote:> On Fri, 15 Sep 2023 12:21:22 -0400 (EDT), Martin Rid > <martin...@verison.net> wrote: > > >Bartolomeo Pestalozzi <bartolomeop...@gmail.com> Wrote in > > message:r > >> Il giorno venerdě 15 settembre 2023 alle 15:01:44 UTC+2 John Larkin ha scritto:> On Fri, 15 Sep 2023 04:57:06 -0700 (PDT), Bartolomeo Pestalozzi > <bartolomeop...@gmail.com> wrote: > > >Hello, > >I am looking for an electric schematic of a telephonic Tone and Probe. > > > >Professional instrumet are like this: > >https://www.fluke.com/en-us/product/network-cable-testers/copper/pro3000f60-kit > >I don't have the pretension nor the ambition to make a similar project. > >I would like to build a simple object to identify the stremity wires. > > > > > > > >Thank you > >Umberto> Amazon has wire tracer kits for around $16. I got one and it's > interesting. You can hear all sorts of e-fields.My purpose was to design one, anyway thanks for the indication. > > > >You can drive a reversed biased diode with a 555 running s a > > frequency in the audio band. This will create a nice broad > > spectrum modulated hash. > >Then use a lm386 audio amp a nd attach the input to a short > > antenna probe as the reciever. > >I used this setup for many years, and it always works. > > > >Cheers > >Cheers > The probe should be very high impedance. Use a jfet or a cmos opamp > and a lot of resistance to ground.I'm starting to lean toward a piezo effect probe. E-field sensors based on a electric field dependent dielectric sandwiched between piezo ceramic plates have been in development for years. Also the piezo is a good way to get very high Q bandpass. It's ultra high-Z all the way. A probe made of this material does have a susceptibility to microphonics- converting vibration to electric.
Reply by ●September 16, 20232023-09-16
On Sat, 16 Sep 2023 12:52:55 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Sat, 16 Sep 2023 04:52:06 -0700) it happened John Larkin ><jjlarkin@highlandtechnology.com> wrote in ><rj5bgitnmcvc1n3iu1nfgtufko7djs77rb@4ax.com>: > >>On Sat, 16 Sep 2023 05:22:45 GMT, Jan Panteltje <alien@comet.invalid> >>wrote: >> >>>On a sunny day (Fri, 15 Sep 2023 13:51:44 -0700) it happened John Larkin >>><jjlarkin@highlandtechnology.com> wrote in >>><7ig9gi5lvb8ho1p4onrtbed451a1ftrmfn@4ax.com>: >>> >>>>On Fri, 15 Sep 2023 16:03:44 -0400 (EDT), Martin Rid >>>><martin_riddle@verison.net> wrote: >>>> >>>>>John Larkin <jjlarkin@highlandtechnology.com> Wrote in message:r >>>>>> On Fri, 15 Sep 2023 12:21:22 -0400 (EDT), Martin Rid<martin_riddle@verison.net> wrote:>Bartolomeo Pestalozzi >>>>>> <bartolomeopestalozzi65@gmail.com> Wrote in> message:r>> Il giorno venerd� 15 settembre 2023 alle 15:01:44 UTC+2 John >>>>>> Larkin ha scritto:> On >>>>>> Fri, 15 Sep 2023 04:57:06 -0700 (PDT), Bartolomeo Pestalozzi > <bartolomeop...@gmail.com> wrote: > > >Hello, > >I am >>>>>> looking for an >>>>>> electric schematic of a telephonic Tone and Probe. > > > >Professional instrumet are like this: > >>>>>> >https://www.fluke.com/en-us/product/network-cable-testers/copper/pro3000f60-kit > >I don't have the pretension nor the >>>>>> >ambition to make a similar project. > >>>>>> >I would like to build a simple object to identify the stremity wires. > > > > > > > >Thank you > >Umberto> Amazon has >>>>>> >wire >>>>>> tracer kits for around $16. I got one and it's > interesting. You can hear all sorts of e-fields.My purpose was to design >>>>>> one, >>>>>> anyway thanks for the indication.>>You can drive a reversed biased diode with a 555 running s a> frequency >>>>>in the audio band. This will create a nice broad> spectrum modulated hash.>Then use a lm386 audio amp a nd attach the input >>>>>to >>>>>a short> antenna probe as the reciever.>I used this setup for many years, and it always works.>>Cheers>CheersThe probe should >>>>>be >>>>>very high impedance. Use a jfet or a cmos opampand a lot of resistance to ground. >>>>> >>>>>Oh, just a cap to the probe tip. The lm386 has 28db of gain. If >>>>> it squeals when you touch the probe tip you got gain. >>>>> >>>>> >>>>>Cheers >>>> >>>>Yikes. LM386 is an ancient bipolar part with < 50K input impedance. >>>>Given, say, a 5 pF antenna/probe, the highpass corner frequency is >>>>about 300 KHz. >>>> >>> >>>I still have some, chip is OK, and still available I think. >>> https://hackerstore.nl/Artikel/310 >>> say 4 USD for the complete amp, inlcuding volume knob! >> >>The 10K pot makes the input impeance even lower, even worse as an >>e-field probe. > >You could always add a JFET or MOSFET, few more cents.Yes, a jfet or a cmos opamp You can make a self-biasing jfet amp with just the jfet and a source resistor to ground. I did that for NASA. It involved rocket tests and alligators.
