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Re: Coaxial cable calculation

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On 4/10/2018 2:28 PM, benj wrote:
> On 4/10/2018 5:33 AM, Trevor Wilson wrote:
>> On 10/04/2018 7:20 PM, benj wrote:
>>> On 4/10/2018 2:42 AM, Trevor Wilson wrote:
>>>> Here's a question that stumped me back in the old slide rule days:
>>>>
>>>> A coaxial cable, having an inner diameter of 0.0254mm (0.001") and
>>>> using an insulator with a dielectric constant of 2.56, is yo have a
>>>> characteristic impedance of 2,000 Ohms. What must be the outer
>>>> conductor diameter?
>>>>
>>>> You guys can locate the appropriate method of calculation.
>>>
>>> You think that nobody is smart enough to even Google?
>>>
>>> Answer is right in Wikipedia, you idiot.
>>>
>>> https://en.wikipedia.org/wiki/Coaxial_cable
>>>
>>> But wait, this takes a little knowledge of mathematics so that lets
>>> you out. Slide rules were a stupid idea when it was a new idea. Hint:
>>> nobody even knows what they are anymore.
>>
>> **I do. I still use a couple. Mostly for intellectual stimulation and
>> a bit of fun. My scientific calculators make life too easy. The nice
>> thing about slide rules is that you need to have a rough idea of the
>> answer before you start.
>>
>>>
>>> Just write L/C take square root set to 2000 and solve for inside
>>> diameter of outer conductor. Like I said you do need to know some
>>> algebra.
>>>
>>> It's obvious you are not asking for the complex impedance since you
>>> didn't give enough information for that. Any idea what we are talking
>>> about here genius?
>>
>> **I note your inability to supply a correct answer.
>>
>> NEXT!
> 
> The idea is the important thing, bunkie!
> I note your usual fantasies of being the smartest person on the planet
> and everyone else being inferior to you.
> 

nothing wrong with that, Trump, Hillary, Putin, Mays, James McGinn, most
all the worlds leaders, Elizabeth Holmes, Martin Shkreli, Rahm Emanuel,
and especially Carlos Danger.

https://www.youtube.com/watch?v=vqJxp7w919o

Trevor asks for one equation, ez google, where one solves for D, but
typically we do not provide answers here for students homework, or
taking tests, and ask them to work through the problem so they can learn.

So, we are kicking this around for a while, to make sure it is past
homework/test time.

But you could go ahead and find the equation, rearrange terms to solve
for D, and post here.  then we can plug in #s.  [also include the cutoff
frequency equation]  Then we can show you where the solution is
impracticable. [like watts, materials, physical realization, delay...]

also realize that Zo is complex, and "characteristic impedance" is
typically limited to a range of frequency, some are broad, some are not,
so there is another term used when the cable is terminated with its
"characteristic impedance" then one measures VSWR and it needs to be
less than 1.2 for high power, and about 2 for other uses. This is also
calculated, and one needs to know frequency bands of intended use, as Zo
will spiral out of 2 VSWR to 20 and greater, or to 0.

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Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-10 16:42 +1000
  Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 05:20 -0400
    Re: Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-10 19:33 +1000
      Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 15:28 -0400
        Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-11 08:36 -0500
          Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-11 14:38 -0400
            Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-11 13:55 -0500
      Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 15:45 -0400
    Re: Coaxial cable calculation Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-04-10 12:24 +0200
      Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 15:37 -0400
  Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-10 10:59 -0500
    Re: Coaxial cable calculation Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-04-10 18:21 +0200
      Re: Coaxial cable calculation Lofty Goat <rlwatkins@gmail.com> - 2018-04-10 11:32 -0500
        Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-10 11:44 -0500
          Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 16:03 -0400
            Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-10 17:18 -0500
              Re: Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-11 08:24 +1000
                Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-10 17:38 -0500
                Re: Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-11 08:42 +1000
                Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-11 07:36 -0400
                Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-11 08:38 -0500
                Re: Coaxial cable calculation Lofty Goat <rlwatkins@gmail.com> - 2018-04-11 21:57 -0500
              Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-11 07:23 -0400
                Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-11 08:39 -0500
                Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-11 11:20 -0500
    Re: Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-11 05:48 +1000
      Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 16:10 -0400
      Re: Coaxial cable calculation Sergio <invalid@invalid.com> - 2018-04-10 17:30 -0500
      Re: Coaxial cable calculation Lofty Goat <rlwatkins@gmail.com> - 2018-04-11 21:57 -0500
    Re: Coaxial cable calculation benj <benj@nobody.net> - 2018-04-10 15:54 -0400
      Re: Coaxial cable calculation Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> - 2018-04-11 06:01 +1000

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