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Old July 17th 03, 05:02 AM
Tarmo Tammaru
Posts: n/a

What might be of interest in this discussion is that after he derives the
impedance of free space, he uses that to find the Radiation Resistance of a
short dipole for dW. Where d is the length of the dipole and W is
wavelength. (I did not want to do Greek letters). He ends up with an
equation of the form

R=377k(d/W)**2 or R=790 (d/W)**2.

As a sanity check let d/W=1/2, which violates the , but still gives a
fairly close answer of 197 Ohms, compared to the actual 168 Ohms. Note that
this is not the same as Feedpoint Resistance because it is not referred to
the current maximum. Kraus does not actually say this, but seems that the
near field would be the mechanism for "matching" this to the far field 377
Ohms. The transmitter only sees the feedpoint, the rest of the universe sees
the whole antenna.

If I interpret it correctly, this 197 (168) Ohms in independent of where you
feed the dipole. Kind of hard to boil several pages into one paragraph,
especially since most of this stuff I haven't seen in decades.

"Dr. Slick" wrote in message

I don't have that book. What does it say?