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From: AMuzi <am@yellowjersey.org>
Newsgroups: rec.bicycles.tech
Subject: Re: Fine Tuning Shifting
Date: Thu, 12 Sep 2024 07:57:23 -0500
Organization: Yellow Jersey, Ltd.
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On 9/11/2024 6:33 PM, Tom Kunich wrote:
> On Wed, 11 Sep 2024 16:57:13 -0400, Zen Cycle wrote:
> 
>> 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.
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