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Inverted Ls for 160 and 80 meters

Pros and Cons of the Dual Band Inverted L Antenna

A dual band/single antenna approach introduces complexity by adding a trap. In fact, some have warned against attempting the antenna due to the trap alone.  Having a single wire to cover the lowbands is tempting, but may not be worth the increase in complexity and probability of failure.


Evolution of the dual band 160/80 meter inverted L using MMANA

The popular inverted L seems to be a good choice for ease of installation, low cost, and design flexibility.

Having driven my ham radio budget into the red with the tower project, I have resorted to using a freeware antenna modeling program: MMANA    The modeling package is based on MININEC which has a number of limitations.

I started with a simple base fed, quarter wave, inverted L for 160 meters.  Wanting to make this a dual band antenna, I decided to put a trap at the top of the vertical section. Given the lack of tall supports for the horizontal wire, I am forced to have a sloped L.  The resulting design is a vertical wire parallel to my tower (hopefully about 3 ft away), 18.5m up to the trap and 19m sloping down.

MMANA 160/80 Meter Inverted L Design N0HR

The feedpoint is a 300 pF series cap an UNUN to match the low impedance. The trap in the LC is at 2.9 MHz and consists of a 25.1 ÁH inductor and 120 pF cap.

MMANA setup inv L


Modeled Performance and SWR Plots: 80 meters

80 meter performance Inverted L






Modeled Performance and SWR Plots: 160 meters

160 meter SWR inverted L plot

160 meter inverted L gain plot




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