Author Topic: Coaxial cable, as a "high BW passive probe"  (Read 632 times)

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Offline points2Topic starter

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Coaxial cable, as a "high BW passive probe"
« on: November 25, 2024, 04:03:16 am »
Hi,
I used the search engine but I found no thread related to that... so, here it is.

Why no info / thread about about it ?
It's weird to me given the price of high BW active probes... I have 2 1GHz active probes but à 1kEur/unit I can't pay higher price.

So, I went back from "nice" active 1GHz active to explore : coax cable as a high BW probe.
And so far so good !
What's your experience about a basic coax cable as a probe ?

 

Offline shabaz

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Re: Coaxial cable, as a "high BW passive probe"
« Reply #1 on: November 25, 2024, 04:25:47 am »
By 'coax as probe' do you mean a resistive (I.e. Z0) probe?

If you Google 'Z0 probe' you'll come across lots of hits, including ones on this site.
 

Offline jonpaul

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Re: Coaxial cable, as a "high BW passive probe"
« Reply #2 on: November 25, 2024, 04:45:33 am »
We used a 50 Ohm scope plugin/input or term, and a coapx BNC direct to a gen or source.

For probe, The Zo Probe is easily made.

BNC>><<Coax (we used RG/174/u) <> 950 Ohm 1% at tip.

Makes a 10:1 Zo probe cost <1$


Reccconend the excellent 1980s Tektronix Circuit Concepts books

Oscilloscope Provbe Circuits Concepts
Oscilloscope Probe Measurements

http://w140.com/tekwiki/wiki/Concepts_Series
https://www.davmar.org/TE/TekConcepts/TekProbeCircuits.pdf
http://archive.org/details/tektronix_Tek_Probe_Measurements

For cable properties see Belden.com

Enjoy!

Jon

An Internet Dinosaur...
 
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Offline jonpaul

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Re: Coaxial cable, as a "high BW passive probe"
« Reply #4 on: November 25, 2024, 09:39:56 pm »
We bought many TEL 10X Zo probes P61536 at cost $35..55

https://w140.com/tekwiki/wiki/P6156

3.5 GHZ the best!

Jon

An Internet Dinosaur...
 



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