Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Zen Cycle Newsgroups: rec.bicycles.tech Subject: Re: RE: Re: RE: Re: RE: Re: RE: Re: RE: Re: Fine Tuning Shifting Date: Wed, 11 Sep 2024 16:57:13 -0400 Organization: A noiseless patient Spider Lines: 185 Message-ID: References: <18yoO.17738$iptd.15227@fx36.iad> <%TrvO.77681$WT8.8844@fx45.iad> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Wed, 11 Sep 2024 22:57:14 +0200 (CEST) Injection-Info: dont-email.me; posting-host="24273a3ebe87c6c3c8a15b8624cedcff"; logging-data="3952473"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+V1TuiYzYebsJbwCc06MCTUtpyuw6UW7o=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:stZYdOI20Z0+Ps2g+ZjnwLJofL8= Content-Language: en-US In-Reply-To: Bytes: 9856 On 9/11/2024 4:22 PM, cyclintom wrote: > On Sat Aug 17 07:20:44 2024 zen cycle wrote: >> On 8/16/2024 6:28 PM, cyclintom wrote: >>> On Fri Aug 16 13:51:44 2024 Zen Cycle wrote: >>>> On 8/15/2024 4:28 PM, cyclintom wrote: >>>>> On Thu Aug 15 14:58:46 2024 Zen Cycle wrote: >>>>>> On 8/15/2024 2:35 PM, cyclintom wrote: >>>>>>> On Thu Aug 15 13:41:38 2024 Zen Cycle wrote: >>>>>>>> On 8/15/2024 1:08 PM, cyclintom wrote: >>>>>>>>> On Wed Aug 14 19:22:06 2024 zen cycle wrote: >>>>>>>>>>> On 8/14/2024 3:35 PM, cyclintom wrote: >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Flunky just talks ahbout crap that he doesn't know about. Notice how >>>>>>>>>>>> he could not answer how you measure the length of a wire >>>>>>>>>>>> electronically? That's because he personally doesn't know how to use >>>>>>>>>>>> an oscilloscope. Which comes as no >>>>>>>>>> >>>>>>>>>> Or, It could be because Jeff answered it as well as I could so I didn't >>>>>>>>>> feel it was worth commenting, but since you insist, here's how you test >>>>>>>>>> cable length with _out_ using dedicated TDR equipment: >>>>>>>>>> >>>>>>>>>> - Connect a pulse generator, an oscilloscope, and the cable under test >>>>>>>>>> together with a T connector (Typically BNC, but adaptors may be required >>>>>>>>>> depending on the equipment. >>>>>>>>>> - set up a pulse generator to single pulse, starting with a 1 nS width, >>>>>>>>>> 5 V P-P. >>>>>>>>>> - Set up the scope to trigger on the single pulse from the generator, >>>>>>>>>> with the pulse from the generator being displayed at the extreme left of >>>>>>>>>> the display. >>>>>>>>>> - Adjust the time base of the oscilloscope until the reflected pulse >>>>>>>>>> appears on the right side of the display while manually initiating the >>>>>>>>>> pulse on the generator.* >>>>>>>>>> - Longer cable lengths may make the returned pulse not quite >>>>>>>>>> discernible. When the trigger pulse is no longer visible, increase the >>>>>>>>>> pulse width until it is visible, then begin adjusting the time base >>>>>>>>>> again until the reflected pules is visible (It may also be necessary to >>>>>>>>>> increase the pulse amplitude). >>>>>>>>>> - Once the reflected pulse is visible, measure the distance between the >>>>>>>>>> trigger pulse and the reflected pulse on the scope as time delay (Hence >>>>>>>>>> the term Time Domain Reflectometry). >>>>>>>>>> - PLug this delay into the propagation delay value for the cable under >>>>>>>>>> test, and do the math. >>>>>>>>>> >>>>>>>>>> * setting up the generator to a repetitive pulse could prove problematic >>>>>>>>>> in that the trigger pulse period my be shorter than the propagation >>>>>>>>>> delay of the cable under test giving a confusing display. A competent >>>>>>>>>> technician could manage it, but given the bizarre and completely >>>>>>>>>> non-nonsensical method you described, it's well beyond your comprehension. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> I particularly liked the part about "BNC" because as we all know the connector type is important >>>>>>>> >>>>>>>> It can be, depending on the application. When would you need an N-type? >>>>>>>> or an F-type? Be specific. >>>>>>>> >>>>>>>>> Because you don't know how to use an oscilloscope you can pretend that anyone wouldn't use repetitive pulses >>>>>>>> >>>>>>>> Pay attention sparky, I didn't write anyone "wouldn't use repetitive >>>>>>>> pulses". I wrote "a repetitive pulse could prove problematic >>>>>>>> >> in that the trigger pulse period my be shorter than the propagation >>>>>>>> >> delay of the cable under test". In a manual set-up they wouldn't >>>>>>>> unless they already had an idea of how long the cable under test was. A >>>>>>>> repetitive pulse isn't require in any case. Is this why you were never >>>>>>>> able to hold a job for more than a year? >>>>>>>> >>>>>>>>> or that the actual pulse with (1 ns?) is important. >>>>>>>> >>>>>>>> I didn't say it was. I selected 1 nS as a matter of convenience. For >>>>>>>> extremely long cables a 1 uS width is more advisable. The important >>>>>>>> point is to have the pulse narrow enough such that the reflection isn't >>>>>>>> obscured by the high level of the pulse. >>>>>>>> >>>>>>>>> It is no surprise that you never got a real job. >>>>>>>> >>>>>>>> Says the guy who never had a job that lasted more than a year. Meanwhile >>>>>>>> my resume includes ten years at HP/Agilent, ten years at Schneider >>>>>>>> Electric, and ten years at my current position. >>>>>>>> >>>>>>>> Still wanna play, sparky? >>>>>>>> >>>>>>>> -- >>>>>>>> Add xx to reply >>>>>>>> >>>>>>> At least you know that "sparky" is a compliment to a real engineer. >>>>>> >>>>>> no, it isn't, it's the name I give to a dog. In the 40 years I've been >>>>>> in this industry I've never heard an engineer referred to as 'sparky' >>>>>> except for a newbie hire who mis-wired a power supply and and blew up a >>>>>> 22000 uF 50V capacitor. It wasn't intended as a compliment. >>>>>> >>>>>>> Diablo Research followed me around buying up all of the companies I developed products for until they got so rich they hired me full time. >>>>>> >>>>>> Cool story bro. too bad it's bullshit. >>>>>> >>>>>>> That you think that R&D shyould be a permanent job at a single company shows how little you know about engineering. >>>>>> >>>>>> And where did I ever write that? I wrote that moving jobs every year is >>>>>> a big red flag to an employer. Besides that, you're the one that wrote >>>>>> "NO ONE EVER LEAVES HEWLETT-PACKARD!!!!!!". >>>>>> >>>>>> If none of the engineers at HP ever left, I guess that means HP wasn't >>>>>> really any good at anything, right sparky? Gawd you're an idiot. >>>>>> >>>>>>> If you had a single thought in your head it would get lost in that vast void. >>>>>> >>>>>> Still waiting on the PWM cable testing reference, and here's a little >>>>>> tidbit for you: >>>>>> >>>>>> Remember when you said TDR isn't used for fiber optic testing, and that >>>>>> 'light lines' is a commonly used term for fiber optic telecom cables? >>>>>> This website discusses Optical TDR techniques, and at no point uses the >>>>>> term "light lines" or PWM. >>>>>> >>>>>> https://www.flukenetworks.com/expertise/learn-about/otdr >>>>>> >>>>>> >>>>>> oh, and still waiting for that call from your lawyer for your libel >>>>>> suit, you drunk-ass bitch. >>>>>> >>>>>> -- >>>>>> Add xx to reply >>>>>> >>>>> >>>>> >>>>> >>>>> >>>>> More proof that you're not an engineer. >>>> >>>> No one I've ever worked with in my 40+ years in this industry has ever >>>> been called 'sparky' except for the aforementioned intern. Your inane >>>> claim is about a valid as claiming I'm not an engineer because I don't >>>> call fiber optics light lines. >>>> >>>> It was also used to refer to Radio operators and Liebermann could >>>> verify that if he wasn't more interested in protecting your intelgrity >>>> from your own comments. >>>> >>>> IF you were called sparky by anyone other than me, it was equivalent to >>>> some calling someone who just wrecked their car 'crash', or someone who >>>> just broke their leg 'skip'. It's not a term of endearment. >>>> >>>> -- >>>> Add xx to reply >>>> >>> >>> >>> >>> You must feel really bad comapring my net worth to yourself. >> >> No, I actually feel pretty good about it. >> >>> All you do is bitch and complain. >> >> HAHAHAHAHAHAAHHH!!!!!!! yeah, _I'm_ the one that does nothing but bitch >> and complain. HAHAHA!!!! >> >>> You never worked at any real electronics work >> >> Funny, my day-to-day activities (indeed my entire career) tell a very >> different story. >> >>> and cry that you don't know terminology so it CAN'T be true. >> >> I don't dry about such things tommy. I do what any responsible >> professional does: I do some research into the issue, then form an >> opinion. You might want to try the former some time, it'll be a lot less >> embarrassing for you. >> >>> What a joke. ========== REMAINDER OF ARTICLE TRUNCATED ==========