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Friday, November 23, 2018

If the Antenna Fits Use It: 80-10 End Fed Half Wave

My backyard in Panama City, FL got cleared of trees and a storage building due to Hurricane Michael. My 80-meter doublet that was supported by a large pine tree is no more. I now have an open slate for antennas. Of course, a tower and a beam are possible.  But short of that what could I do.

I finally decided to try the 80-10 EFHW 1K. I have used it for Field Day with success. EFHW is End Fed Half Wave. For 80 meters an EFHW is roughly 130 feet. Fed from the end it has a high impedance and requires a matching transformer. I am pretty sure the EFHW has a 49 to 1 Unun in the box. On the harmonics, the antenna is a multiple of a half wave and has the same impedance at the end. That covers 80, 40, 20 and 10.  However, the antenna is quite usable on 30, 15, 17 and 12 meters also. I checked the SWR on all bands in the shack. The SWR is under 2 to 1 on the lower half of 80 meters, 40 meters, 20 meters, 30 meters, 15 meters, and 12 meters. 30 meters is under 2.4 to 1. This is the closest to a tuner-less antenna I have used. 80-10 EFHW 1K

Physically, I took advantage of my patio cover, camo poles and my scraggly popcorn tree that made it through the storm, I had previously wanted to cut that tree. I used a 16-foot camo pole at the feed point, a 20-foot camo-pole, and the tree limb to support 80 feet of the antenna. The last 40 feet of the wire slopes to the back fence at a 90-degree angle to the rest.

This link gives some insight into the radiation pattern. I should do my own EZNEC model for my particular layout. Anyway, we will see how it plays out on the bands. Since I am not a DXer or Contester I think it will do fine.