*FREE online resources for modeling and analysis:*
SimSmith:
SimSmith Tutorial:
EZNEC: (Some limitation
with the free version)
4NEC2: (My
favorite - many hooks and options, more powerful than EZNEC)
KIND WARNING: Don't jump directly into 4NEC2 unless you are well versed in
antenna modeling and design. Learn to deal with EZNEC before tackling
4NEC2.
Dave - W?LEV
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On Mon, Nov 2, 2020 at 7:23 PM <ac7lx@...> wrote:
You should note his comment about using it as the driven element in a
Yagi. When one adds parasitic elements (i.e. yagi), the feed-point
impedance will change in accordance with said parasitic elements and
spacing. As another responder posted, this can be seen in antenna
simulations.
Case in point, the proverbial direct fed yagi found all over the internet.
The driven element, while basically a dipole (75 ohm impedance), by adding
a director and reflector with the correct spacing, the feed-point impedance
drops to ~50 ohms.
Somewhat related to this topic, you might want to look into twelfth-wave
matching using sections of feedline of different impedances to convert from
one Z to another.
As yet another responded mentioned, SimSmith (highly recommended & free),
lets you examine many scenarios and will perhaps, provide some deeper
insight into impedance.
:)
--
*Dave - W?LEV*
*Just Let Darwin Work*
