dansawyeror wrote:
I am assuming the reflection angle of 0j terminations would all be the
same (you said 180), this includes both resistive loads and an antenna
at resonance. The method I am using relies on that.
I am confused about one thing in the smith chart program. Cables
identified as stubs create a circle that goes through infinity and do
not exhibit a constant SWR, while simple cables create a constant SWR
circle with the center and 50 Ohm 0j.
I believe the setup I am testing exhibits the constant SWR characteristic.
No real-world transmission line exhibits a constant SWR since
no real-world transmission line is lossless. Constant SWR
circles are approximations. The actual SWR curve is a spiral
from a point on that constant SWR circle that, in the limit,
spirals down to the Z0 of the line.
For instance, using Owen's feedline calculator, the SWR at a
500 ohm antenna fed with 100 feet of RG-58A is 10:1 and the
SWR at the other (source) end is 1.42:1 for 146 MHz.
--
73, Cecil
http://www.qsl.net/w5dxp