[Heathkit] Fwd: My Earlier Post

[Nick England]

OK, I wasn't going to say anything but since others are talking about
it, I'd like the chance to set the record straight - I am the engineer
in question and I certainly didn't try or mean to chastise Don and
have apologized to him. I tried to make a joke about being a
"professional engineer" because he made a joke about probably being
wrong because "we're all amateurs".

I sent what was intended and what I thought was a helpful,
light-hearted private message trying to explain cable capacitance
which his mail indicated he was confused about. But sometimes things
just don't come across as intended.
No good deed goes unpunished as they say.
End of topic I hope.
73 to everyone,
Nick K4NYW

======= What I sent Don ========
Hi Don  --
Well, I'm a radio amateur but a professional electronics engineer -
the capacitance of cable is indeed from conductor to conductor (center
to shield on co-ax) so it is definitely a shunt on the signal, not a
series capacitance. Just think about how a capacitor is made - a
sandwich of a conductor, a dielectric insulator, and another conductor
- make the area of the sandwich bigger and the capacitance goes up,
make the dielectric thicker and the capacitance goes down. Co-ax is
just a funny shaped sandwich.

For the purposes of this discussion I'm assuming a short piece of
co-ax compared to a wavelength. because cable acts like a transmission
line as it gets longer and that's a whole 'nother kettle of fish. The
transmission line can be viewed as a endless array of series inductors
and parallel capacitors (and the L/C ratio determines the
characteristic impedance Z=sqrt(L/C))

--L---L---L---L---L---L---L---L---L---L.......
   |    |    |    |    |    |    |    |    |  ......
   C  C   C  C  C  C   C   C   C
   |    |    |    |    |    |    |    |    |  ......
------------------------------------------------.......

cheers,
Nick K4NYW
====== What Don posted ========
>My apologies to the group for trying to be helpful earlier.  I was
>sufficiently chastised off list, by a "professional engineer".  I'll just
>stick to helping with parts, etc when I can and re-enter my cave.
>73,
>Don, WB5HAK
====== My reply to that ===========
Oh come on, Don. You ended your mail with "but we're all amateurs" so I was
just trying to make a joke. I do apologize for offending you. That certainly
was not my intention and was just trying to help you better understand a
complex subject.

Please accept my sincere apologies from a fellow who cheerfully acknowledges
he is downright ignorant about many many things.
73
Nick K4NYW
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