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Path: ...!news.roellig-ltd.de!open-news-network.org!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Jeroen Belleman <jeroen@nospam.please> Newsgroups: sci.electronics.design Subject: Re: RF Metrology Date: Sun, 6 Oct 2024 19:44:23 +0200 Organization: A noiseless patient Spider Lines: 48 Message-ID: <vdui3d$1aevd$1@dont-email.me> References: <mu1jfjtd6521pp9nb0kubcorkkkdh20gu3@4ax.com> <vdubbp$19e91$1@dont-email.me> <kph5gjd7ha4mqhhcnp761fief08km5edqj@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sun, 06 Oct 2024 19:41:02 +0200 (CEST) Injection-Info: dont-email.me; posting-host="f97282f2d3c6e24d0094e8d991cce82c"; logging-data="1391597"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18SQgeyGoCt/59Y46SKYDSg" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Cancel-Lock: sha1:c4S/bybuLWvVe6b62HoW0VigsoI= In-Reply-To: <kph5gjd7ha4mqhhcnp761fief08km5edqj@4ax.com> Content-Language: en-US Bytes: 3766 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