Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Phil Hobbs Newsgroups: sci.electronics.design,sci.electronics.repair Subject: Re: Francophones Date: Tue, 24 Dec 2024 01:16:31 -0000 (UTC) Organization: A noiseless patient Spider Lines: 55 Message-ID: References: <84fbmj56f92g7uspk4h5e04qj1vgri925o@4ax.com> <1r4vq2s.1tmc4wm1iuvgp4N%liz@poppyrecords.invalid.invalid> <1r4wrcj.5sbtfti811qyN%liz@poppyrecords.invalid.invalid> <95idmjpun3fqc5d4ud98havpjs4qo2iqnk@4ax.com> <1r4ynfn.b59oq9u83h8qN%liz@poppyrecords.invalid.invalid> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Tue, 24 Dec 2024 02:16:31 +0100 (CET) Injection-Info: dont-email.me; posting-host="9b626ff6ae23602d235c8740601ac6c4"; logging-data="1566556"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+DzuGcWkliUu+Zjz54u9GT" User-Agent: NewsTap/5.5 (iPhone/iPod Touch) Cancel-Lock: sha1:Ny8bLdXdWfnp69HLVeqQatNqShs= sha1:f2kpWyKKFdwXVek+eCJJ5hAXSzQ= Bytes: 4086 Ian Jackson wrote: > In message , Jeroen Belleman > writes >> On 12/23/24 18:58, Ralph Mowery wrote: >>> In article , noreply@ademu.nl >>> says... >>>> >>>> On 2024-12-23 16:22, Ian Jackson wrote: >>>>> For many purposes you can ignore the difference between the 50 and >>>>> 75 ohm impedances (and 60 if you ever come across any). >>>>> However, be very aware only BNC 50 and 75 ohm connectors are >>>>> mutually mechanically mateable (yes - they really are!). I don't >>>>> know if any others that are. >>>> >>>> Not recommended. >>>> The center pin differs, a 50 Ohm BNC pin is thicker and may damage a >>>> 75 ohm BNC. >>>> I'm cautious, most of my below 1 GHz equipment is 75 Ohms (from CATV >>>> company), the rest is 50. >>>> >>>> >>>> >>> It is the N connector the center pin is different. The BNC pin is >>> the >>> same. It is the ammount of dialectric (insulation) in the BNC that >>> makes it a 75 or 50 ohm connector. >>> >> >> N connectors are good, but the fact that 75 and 50 Ohm connectors >> are similar enough to mate, but not nearly enough to do so without >> damage or malfunction is perverse. When I took charge of the >> electronics lab, it took a while to sort them out and to eliminate >> the victims of mismatched matings. (I was always amazed at the >> sheer quantity of connectors in a busy lab.) >> >> For BNCs, there *is* a difference, but it doesn't usually matter. >> I kept 50 and 75 Ohms separate, but when put to the test, many >> 75 Ohm connectors turned out to really be 50 Ohm ones in disguise. >> >> In a pinch, BNC and N can even mate between them. I'm not sure if >> that's deliberate or accidental. >> > Yes - the 'innards' are essentially the same. IIRC, the BNC innards also > mate with C-connectors. I think it's deliberate. After all, its the > innards that carry the RF. A type N male will also mate with a BNC female. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics