80m EFHW

This will be an on-going post, as I'm documenting this... adventure... while experiencing the fun of working with this thing.

9/4/2025:

As I begin writing this, I don't have an antenna for the lower HF bands. My previous antenna, a 500' loop, came down over the winter and I've not been concerned enough to put it back up. I wanted a quick fix to get something out there for now, so I decided to try out the EFHW design that seems to be so popular with the portable crowd.

I read that, if cut for the lowest band of operation, they load reasonably well other bands. I really only need this thing for 80 and 40 meters, so I went with a roughly a half-wavelength at the middle of 80m. It's actually a bit longer than that, since most websites say to cut 130'. I figure it's best to have too much than not enough, so I went with everyone else instead of my own math. It's easy to remove wire anyway.

486 / Mhz = Length (ft)

468 / 3.97 = 118ft                    468/3.75 = 125          468/3.55 = 131.83

I picked up an inexpensive 1:64 balun off Amazon (sorry people, needed it next day, not next week). While it's only rated at 100w, that's the most power I can put out, so it's not a concern. I attached roughly 130' of 14ga solid copper wire for my radiating element. Figuring this would be a quick endeavor to try out, I hung the balun on my tower about 6' off the ground, and found a far-away tree branch to hoist the wire.

One problem: Do you know how heavy 130' of 14ga solid copper wire is when it's fully unrolled? Being 6' off the ground at one end and 15' off the ground at the other, this thing was pretty much at decapitation height for its entire length. My rope (glorified twine) broke twice and I got a pop bottle full of water stuck in the tree.

So, off to the hardware store tomorrow to get some actual rope-rope to hoist this thing. I also plan on hanging the balun up about 25'. High enough to keep this big saggy wire off the ground, but also right next to my TV antenna. Surely that won't cause RFI issues, right?

Update: 9/7/2025

Well. I have to say I'm pleasantly surprised! I went up the tower and mounted the feedpoint at about 30'. The other end is supported by a tree branch at about 20 feet. Not as high as I wanted, but I couldn't throw the launch bottle any higher. There's an "air choke" about 18" in diameter of around 10 turns at the tower base. Aka, I wound the extra coax around the plastic box where all my coax connections meet up.

I was rather cautious as I loaded it up the first time, and it turned up as quickly as a dipole. I was able to check into nets on 40 and 80m with very good signal reports. And I don't seem to have any RF getting into the shack. 

It won't load on 160m, but that's not much of a surprise. I didn't expect it to, so no big loss there. Besides, my 500' loop covers that band well. When it isn't in a coil on the picnic table waiting to be put back up, anyway. Ha.