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NNTP-Posting-Date: Mon, 08 Apr 2024 01:38:18 +0000
From: John Larkin <jl@997PotHill.com>
Newsgroups: sci.electronics.design
Subject: Re: Scope Probes off Ebay
Date: Sun, 07 Apr 2024 18:36:36 -0700
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On Mon, 8 Apr 2024 11:06:52 +1000, Chris Jones
<lugnut808@spam.yahoo.com> wrote:

>On 8/04/2024 2:57 am, John Larkin wrote:
>> On Sun, 07 Apr 2024 14:51:29 +0100, Cursitor Doom <cd@notformail.com>
>> wrote:
>> 
>>> I never learn. I bought a used "Agilent 500Mhz probe" off Ebay for 50
>>> quid as the highest bandwidth probe I thought I had was a 150Mhz Tek
>>> one. Anyway, I have a large selection of old probes lying around so
>>> decided to check to make sure the "Agilent" one was genuine. Not
>>> surprisingly it turns out it isn't. I haven't calculated what it's
>>> real bandwidth is. I've established it's not as sensitive as the
>>> 150Mhz one and that's all I need to know. Whilst I was going through
>>> this palarva, I tested a old probe I came across that I've never used
>>> before and was amazed at the improvement in signal I got with it. I've
>>> just Googled its part number and it turns out it's a 3.5Ghz passive
>>> probe! I never even knew I had one so fast. I would never have ordered
>>> the "500Mhz" one if I'd known I had this forgotten-about one already.
>>> So the fake's going back for a refund and I won't be ordering  any
>>> more probes from anywhere in the forseeable future.
>> 
>> The HP54006 is a 6 GHz probe, into a 50 ohm scope.
>> 
>> https://www.dropbox.com/s/lxq4ujmkvo755uy/HP54006_probe.zip?dl=0
>> 
>> They show up on ebay now and then. There's one now, asking $150.
>> 
>> You can make your own with some of those Caddock resistors. The
>> Caddocks have some magical recipe. And unlike a fet probe, they are
>> hard to damage. I use them to probe 7 ns 1400 volt spikes in my
>> Pockels Cell driver.
>> 
>> And you can do a GHz at least with a 1-cent axial or mini-MELF or 0805
>> resistor on the end of a coax. 450 ohms makes a 10:1 probe. Fast
>> circuits are often low impedance circuits and don't mind a 500r or 1K
>> load.
>> 
>
>
>Which Caddock part number?

In the zip file.