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Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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10th Jun 2023, 12:25 am | #1 |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
Posts: 194
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RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Buildind probes for VTVM, TVM, VOM , DVM and Oscilloscopesbuilding probes.
I am building my own probes for my VTVM and Oscilloscope. Hope popes the photos and schematics of there probes. Dave Latest probe quadruple for AF and RF work and RF for VOM uses |
10th Jun 2023, 3:30 pm | #2 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Hi Dave
this is a subject which has been discussed a lot on the forum over some years. One subject of interest has been the really good results that certain companies have achieved with their probes (e.g. Boonton and Marconi) which amateurs have found hard (impossible?) to replicate. The 1SS86 silicon schottky is a diode which may be worth a try. B
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10th Jun 2023, 4:45 pm | #3 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
It is problem with almost all groups.
The only fix is sticky threads. Here photo of my probes from a old wind-chime and drawing in pdf on how I did the probes. Dave Quote:
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10th Jun 2023, 10:53 pm | #4 |
Octode
Join Date: Jul 2018
Location: Worthing, West Sussex, UK.
Posts: 1,002
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
It is too late for me to think straight. Is the 4 diode version like a full wave voltage doubler?
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12th Jun 2023, 1:30 am | #5 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Here some history I found on internet on the Quadruple
Quote:
Dave Last edited by Smithdoor; 12th Jun 2023 at 1:38 am. |
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12th Jun 2023, 3:09 am | #6 |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
Posts: 194
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
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12th Jun 2023, 10:13 pm | #7 |
Octode
Join Date: Jul 2018
Location: Worthing, West Sussex, UK.
Posts: 1,002
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
It dates back to 1910s
At least I am a mere 110 years behind the times, that is good for me
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"Behind every crowd, there's a silver Moonshine" |
12th Jun 2023, 11:03 pm | #8 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
I don't recall seeing a commercial probe using 4 diodes.
I think it is also the case the the really good instruments like the Boonton had closely matched probe/amplifier combinations. B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
13th Jun 2023, 11:48 am | #9 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Quote:
But only found half wave too. I was looking for full wave and only found shop made. Dave |
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14th Jun 2023, 12:23 am | #10 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Quote:
If add a 4.7 resistor to schematic it is very common probe. The Quadruple is just two Greinacher circuit for full wave probe. The Greinacher circuit is 20hz to 50Mhz it even use tube version on older VTVMS Dave |
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14th Jun 2023, 1:20 am | #11 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
This is from 1984 ALLR Book for probes.
Quote:
Last edited by Smithdoor; 14th Jun 2023 at 1:25 am. |
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14th Jun 2023, 5:30 pm | #12 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
There's a good article on Boontons here http://ve2azx.net/technical/RF-Probes.pdf.
For some reason, that does not open in Chrome unless I go incognito. B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
14th Jun 2023, 10:13 pm | #13 |
Octode
Join Date: Jul 2018
Location: Worthing, West Sussex, UK.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
I will have a go at constructing the quadruple probe as soon as I can find a case to put it in. An old sharpie type pen or cigar tube will do.
I will compare it to my single diode design taken from an old Pye manual (probably Cambridge).
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"Behind every crowd, there's a silver Moonshine" |
14th Jun 2023, 10:21 pm | #14 | |
Dekatron
Join Date: Apr 2009
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Quote:
B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
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14th Jun 2023, 10:34 pm | #15 |
Octode
Join Date: Jul 2018
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
I will just test with a sig gen and measure level on an AVO 8 and compare levels and freq. response. Not an exhaustive test, more a comparison.
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"Behind every crowd, there's a silver Moonshine" Last edited by Cruisin Marine; 14th Jun 2023 at 10:44 pm. |
15th Jun 2023, 2:16 am | #16 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
The download is great Thank you
I will make a real drawing in next few days and post it here. Dave Quote:
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15th Jun 2023, 2:39 pm | #17 |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Schematic of first
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17th Jun 2023, 9:00 am | #18 |
Heptode
Join Date: Oct 2005
Location: Olympia, Washington, USA.
Posts: 664
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
We are lucky these days with the solid state parts. My old Sylvania Polymeter used a loctal tube in the RF probe.
That quad probe looks quite interesting. I wonder how 1N21 diodes would work in that config.? |
17th Jun 2023, 2:37 pm | #19 | |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
Quote:
The 1N34 goes to 250Mhz. My probes are built in side a 12mm tube for good hand fit. Aka old wind-chime Dave |
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18th Jun 2023, 7:06 pm | #20 |
Pentode
Join Date: May 2023
Location: Clovis, California, USA.
Posts: 194
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Re: RF and AF probe for VTVM, TVM, VOM , DVM and Oscilloscopes
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