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From: john larkin <JL@gct.com>
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Subject: Re: RF Metrology
Date: Sun, 29 Sep 2024 14:21:51 -0700
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On Sun, 29 Sep 2024 22:08:25 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 9/29/24 20:57, John R Walliker wrote:
>> On 29/09/2024 19:02, Jeroen Belleman wrote:
>>> On 9/29/24 19:14, Cursitor Doom wrote:
>>>> Greetings, gentlemen,
>>>>
>>>> [...] 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?
>>>>
>>>> Your pal,
>>>>
>>>> CD.
>>>
>>> Aren't we getting a teensy bit lazy?
>>>
>>> Jeroen Belleman
>> 
>> I have seen transmission (S21) losses of around 1dB at about 1.2GHz
>> just from failing to tighten an N connector sufficiently.
>> We do need to know the magnitude and frequency of the problem in
>> order to give helpful comments!
>> John
>> 
>
>I collected some TDR traces of various connectors, adapters and
>terminators a few years ago: <https://cern.ch/jeroen/connectorTDR>.
>
>There were a few surprises. I was taken aback by the poor results
>for H+S BNC and LEMO-00. For BNCs, Radiall is better than H+S, but
>for N-connectors, it's the reverse.
>
>After having seen what LEMO-00 hardware did to my signals, I was
>pleasantly surprised by the performance of SMC.
>
>SMA was the best I had around, hands down, no surprises there.
>
>Jeroen Belleman

SMBs are surprisingly good, and easier to use.

Shining Star makes nice, crazy cheap, edge-launch SMAs and SMBs.

https://www.dropbox.com/scl/fi/x8w5izvfvg87bit10vty4/SS_SMB_Edge.JPG?rlkey=8xsf1wlw73wopi9vlf0slh52g&raw=1