Modeling the Double L Antenna on a 70 ft Tower
I had stumbled upon K2KQ's interesting Double L
design on the
It seemed to be a likely candidate for my application as it had several
My next step was to model the Double
model of the Double L included a tower and a yagi as used in other models.
The K2KQ design calls for two dipoles bent into a C shape and connected at
about the midpoint of the tower (mounted about 3 ft away). The 160 meter
dipole is 270 ft. and the 80 meter dipole is 130 ft. In my model, I had to
account for sloping elements due to a lack of surrounding trees/supports.
Here is the model of the Double L as it would appear on my 70 ft ANWireless
SWR & Bandwidth
The bandwidth on 80 meters looks to be excellent for the
Double L. It's easily useable across the entire band with little effort. If
an adjustment was necessary, it would be easy to tune by changing the length
of the lower element.
The 160 meter SWR plot of the Double L is shown below. I
was unable to tweak the antenna to a perfect match. However, the 58 Hz below
2.0:1 is not too shabby.
Far Field Plots
The far field plot for the Double L 80 meters shows a lot of energy lost
to high angles. I suppose this antenna is simply looking more like a dipole
than an Inverted L on 80 on my tower.
The 160 meter plot shows a decent pattern.
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