End-Fed Half-Wave (EFHW) 40m-10m
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| Frequency | 7-30 MHz (40/20/15/10m) |
| Bands | 40m, 20m, 15m, 10m |
| Modes | SSB, CW, digital |
| Connector | SO-239 |
| Year | 2010 |
| feedpoint | SO-239 |
A practical portable wire antenna: a 66-foot wire fed at one end through a 49:1 UNUN, covering 40m, 20m, 15m, and 10m with low SWR and no tuner on most bands. It needs only one support point because the feed is at one end, so the far end goes over a branch and you operate. It has become a dominant portable HF antenna for POTA, SOTA, and Field Day: lightweight, deployable in minutes, and effective on four bands from a single wire.
The 49:1 transformer is the critical component; cheap cores (wrong ferrite) fail under power. Common-mode current on the feedline is a persistent issue without a choke at the transformer. Performance is sensitive to height, routing, and nearby objects. The 40m bandwidth is narrow. The WARC bands (30m, 17m, 12m) are not harmonic and need a tuner. There is high voltage at the wire end; keep it clear of people and structures.
A popular portable HF wire antenna. Throw one end over a branch, connect the transformer to the radio, and you are on four bands. The EFHW displaced the dipole as a default portable HF antenna because it needs only one support and feeds at the operator's position.
The EFHW-4010 is an end-fed half-wave antenna for the 40 through 10-meter bands — a design that has exploded in popularity for portable, POTA, and field operating because it is simple, light, and resonant without needing a tuner. It is a single wire about 66 feet long (a half wavelength on 40 meters) fed at one end through a 49:1 impedance transformer, called an unun, which steps the very high end-feedpoint impedance of roughly 2,500 ohms down to the 50 ohms your coax and radio want.
Because a half-wave on 40 meters is also resonant on its harmonics, the same wire works on 40, 20, 15, and 10 meters with a usable match on each — no antenna tuner required, which is a big convenience in the field. It typically wants a short counterpoise wire for a return path, and end-feeding means you can support just one end from a tree or mast and run the wire off as a sloper or inverted-V.
It is a current, widely sold and homebrewed design and a favorite for go-kits. The G5RV is the classic tuner-fed multi-band wire alternative, and a plain long wire is the simplest end-fed option of all.