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From: john larkin <jl@glen--canyon.com>
Newsgroups: sci.electronics.design
Subject: Re: RF Metrology
Date: Mon, 07 Oct 2024 10:28:20 -0700
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On Sun, 6 Oct 2024 19:44:23 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 10/6/24 19:26, john larkin wrote:
>> On Sun, 6 Oct 2024 17:46:02 +0200, Klaus Vestergaard Kragelund
>> <klauskvik@hotmail.com> wrote:
>> 
>>> On 29-09-2024 19:14, Cursitor Doom wrote:
>>>> Greetings, gentlemen,
>>>>
>>>> I bought one of those TinySA Ultras recently and have spent some time
>>>> testing it today. I have to say it's amazing what they've done for the
>>>> price. I mean, truly amazing. I do have two other 'proper' lab-grade
>>>> RF spectrum analyzers, but I think I'm going to be mostly using the
>>>> TinySA in future as it's just *so* convenient and doesn't weigh a ton.
>>>> Anyway, to get back to the point of this post, having checked out the
>>>> TSA and establishing I didn't buy one of the fake versions that are
>>>> out there, I turned my attention to my mid-level RF SA, an HP who's
>>>> model number escapes me (not the 8566B I've posted here about before
>>>> which is now fully working, but a newer model that's about 1/3 as
>>>> heavy. I say I can't recall the model number but it's not relevant to
>>>> this question anyway. "So what is the fucking question, CD??" I hear
>>>> you not unreasonably cry. Well, it's this:
>>>> When I'm feeding an RF signal into the SA, I'm seeing differing
>>>> amplitudes at different frequencies. So I've programmed in a sweep
>>>> from 10Mhz to 5.4Ghz at -49dBm using my Aeroflex RF signal generator
>>>> and I'm seeing the displayed amplitude vary as it sweeps through the
>>>> range. But this only happens when I'm using a cheap, Chinese N-type to
>>>> SMA adaptor at the signal generator output. Would I be right to
>>>> suspect some imperfection in the manufacturing of the adaptor could
>>>> cause such an effect? I do have a VNA I could characterize the adaptor
>>>> with but it's a bit of an effort to do. It would seem like the SA is
>>>> showing the adaptor's shortcomings in the frequency domain. But is
>>>> that a feasible hypothesis?
>>>>
>>> Measurement of good vs bad cables:
>>>
>>> https://www.youtube.com/watch?v=AqFDxQjJAdA&t=50s
>>>
>> 
>> I solved a billion-dollar showstopper last year. Some country started
>> demanding that some expensive semi fab gear be EMI tested, and our
>> units failed. After great hassle we traced it to bad ground crimps on
>> shielded CAT5 cables that our customer bought cheap.
>
>I bought a set of phase-matched cables from Taiwanese company
>JYEBAO because my usual supplier Huber & Suhner failed to
>answer a quote request. I was pleased to find that JYEBAO's
>cables were *better* than H+S, and cheaper too.
>
>Jeroen Belleman

So ar, the generic cheap Amazon SMA and SMB cables have been
excellent. As have been the edge-launch connectors.

The Shining Star connectors are great too.