Here is my 2 cents worth. First of all, I am not an antenna expert nor do I
know how to use antenna modeling software.These are my thoughts based on my
experience and what I remember reading. My low band system is an inverted L
under a SteppIr yagi that can be retracted. This avoids the capacitance hat
effect on the inverted L.
The capacitative top hats you have on your tower make the inverted L "appear"
longer thus requiring morecapacitance to match the inverted L. If there were
no yagis to create capacitance over the inverted L, the antenna would appear
shorter and require less capacitance to match. Capacitative matching is less
lossy and more efficient than inductive matching from what I remember.
I am posting this to see if anyone can add-to or correct my comments.
Noel Lopez NR5R
On Wednesday, December 20, 2023 at 07:52:00 PM CST, Steve Muenich
<srmuenich@gmail.com> wrote:
I have an Inverted-L question that hopefully someone can answer for me.
I installed the 160m wire to the 80 ft level on a 100 ft Rohn 45 tower
with top mounted yagis.
The horizontal (sort of) portion is approx 45ft long.
The wire starts at 80 ft down approx 5 ft from tower and when it gets to
the match box the bottom of the wire is about 10ft away from tower.
I have about 50 or so 120 ft long radials.
I am able to get a X=0, R=52. SWR 1.19:1 tune according to my RE Zoom using
load shunt match at base of tower.
My question is why do I need so much series capacitance (5300pf) with
parallel inductance approx 8uh?
Everything is working fine, but I am wanting to understand why I am needing
so much series capacitance? Does this indicate an issue I need to resolve?
TIA,
Steve, NA5C
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