At 09:26 PM 10/3/99 -0500, you wrote:
>
>Larry Molitor wrote:
>
>>>The
>>>50+j0 point on a Smith Chart is the very center of the chart. A VSWR has
>>>the 50 Ohm point as its center.
>>
>>Nope. The center on a standard Smith Chart is 1.0 ohms. You are either outa
>>school too long or never knew it to begin with. Remember the little part
>>about normalization? 50 ohms is neither sacred nor universal.
>
>PICKY, PICKY, PICKY!
If I didn't pick at you, someone who is less charitable would.
>But generally when an RF engineer talks about the 50 Ohm point on the
>Smitch Chart, he means the center since 50 Ohms is the standard for most
>RF communications (Television is an exception).
Most engineers I know don't assume 50 ohms since the military contract jobs
went away. I bet the cable plants turn out more 75 ohm coax everyday then
50 ohm. I personally have purchased about 10,000 feet of 75 ohm coax in the
last few months. That includes Heliax as well as flexible types of several
different diameters. None of which is used in a television application!
73,
Larry - W7IUV
w7iuv@arrl.net
http://www.axtek.com/w7iuv
Amp pix at http://207.108.137.61
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