Find a Tree, Hang a Wire
One of the things I appreciate about amateur radio is that sometimes the simplest solutions are also the most effective.
You can put up towers, beams, and rotators, and many operators do. But some of the most satisfying contacts I have made came from something far less elaborate: a length of wire, a transformer, and a nearby tree that was kind enough to cooperate.
That is essentially the idea behind the end-fed half-wave antenna (EFHW).
Electrically, it is a half-wave radiator fed at the end rather than the center. Because the impedance is extremely high at that point, a 49:1 transformer brings things back into a range that ordinary coax and radios can live with.
Once that happens, it behaves very much like a dipole. The real advantage, however, is mechanical rather than electrical.
- A dipole wants three support points.
- An EFHW is content with one.
Which means if you can toss a line over a limb, you can usually get on the air.
Why Portable Operators Love the EFHW
Portable operators discovered this long ago. POTA activators, field operators, and travelers like antennas that go up quickly and disappear just as fast. A coil of wire and a small transformer can live quietly in a backpack until needed.
The transformer, incidentally, is the part that deserves the most care. When they are poorly wound, they heat up, waste power, and behave badly across bands. When they are built correctly, they simply do their job and stay out of the way.
That quiet reliability is exactly what you want in an antenna system.
Over time I started winding transformers for my own EFHW antennas. A few friends asked for them, then a few more, and eventually that turned into a small Etsy shop where I offer a couple of versions of the ones I use myself.
The transformers I build are nothing exotic, but they are wound carefully on quality ferrite cores, sealed in weather-resistant enclosures, and tested before they ever leave my bench. They are the same ones I use when I throw a wire into a tree and see what the bands are doing that day.
If you enjoy winding your own transformers, I encourage it. Half the fun of amateur radio is experimenting and learning what works.
But if you'd rather skip the ferrite dust and get straight to the operating part, you can take a look here:
Either way, the basic advice remains sound: Find a tree...Hang a wire...See who answers!
- 73 Dave
