Half-wave end-fed (HWEF) antennas have gained popularity among amateur radio operators for their simplicity, versatility, and ease of installation. While they have a few notable benefits, they also have many problems that make them less than ideal. Here's why I'm not totally sold on HWEF antennas.
The Benefits of HWEF Antennas
HWEF antennas are often chosen for their straightforward setup. With only one end requiring support, they can be strung up between a single tree or pole and a ground point or a corner of the house, making them perfect for tight spaces or quick deployments during portable operations.
Many HWEF antennas can work across multiple bands with the help of the transmitter's internal tuner, offering operators flexibility without the need for additional antennas or an external tuner.
Their physical footprint is relatively small, which makes them a good choice for quick deployment for POTA or SOTA operations or operators with HOA restrictions. Operators with HOA restrictions also like these antennas for their relative stealthiness.
HWEF antennas consist of two components: a wire and a transformer. Compared to other antennas, HWEF antennas are often cheaper and relatively easy to build, making them appealing to new hams or operators on a budget.
Problems with HWEF Antennas
Despite these benefits, HWEF antennas have issues that compromise their performance and practicality, especially for serious amateur radio operators.
Here's why I'm not a fan
Claims that HWEF antennas don't require counterpoises aren't entirely accurate. The coaxial feed line acts as the counterpoise, introducing additional RF noise into the system and significant common mode currents on the coaxial cable shield. This can wreak havoc on station equipment, the shack, or the house's electric equipment, such as GFCI breakers, thermostats, etc. When transmitting with high power, especially on lower bands, "RF burns" are a common issue, making the entire setup unsafe. Limiting the common mode current by adding chokes at strategic places is required. Sometimes, other countermeasures are also a necessity, complicating what's supposed to be a simple antenna system.
One way I like to think of the EFHW antenna is that it's actually an "extreme OCFD." It's not possible to feed a half-wave wire from the very end; there always has to be "the other end". In the case of the EFHW, there is either a short intentional counterpoise wire on one side of the transformer or the coax is the counterpoise.
HWEF antennas relying on compact matching units often suffer from inefficiency due to poor impedance matching. Losses in the transformer, long feed lines, and antenna tuners can significantly degrade performance, especially on lower bands with higher voltages at the feed point.
Since HWEF antennas are unbalanced systems, they tend to pick up more local noise than balanced antenna designs like dipoles, for example. This makes them less ideal in noisy environments, especially for phone operations where every decibel of signal-to-noise ratio matters.
The end-fed design has very high feed-point impedances, exceeding several thousand ohms. While matching transformers (often 49:1 or 64:1) can help, they introduce inefficiencies and can be tricky to build or tune properly. This complexity undermines the "simple" appeal of home brewing an HWEF antenna.
High voltages at the feed point mean that HWEF antennas are prone to arcing, particularly during high-power operations or when moisture collects near the feed point. This makes them less reliable over time, especially in wet or humid climates.
While HWEF antennas can be versatile in terms of installation, their radiation pattern is highly dependent on the mounting height, shape, and orientation. This can result in sub-optimal coverage on some bands, mainly if the antenna cannot be installed high enough. Since the coax shield is also part of the antenna (radiating), it results in unpredictable polarisation and radiation patterns.
Why I Don't Like HWEF Antennas
While I acknowledge the convenience of HWEF antennas, their drawbacks outweigh their benefits for my needs. They may be fine for quick setups, portable operations, or beginners exploring HF bands. Still, their inefficiency, noise susceptibility, and high RF common mode currents make them unsuitable for reliable, high-performance communication.
If you're looking for a multi-band antenna system that provides reliable performance, consider alternatives such as center-fed dipoles, off-center-fed (OCF) dipoles, or vertical antennas with an appropriate radial system. While these options may require more effort to install, they offer superior performance and reliability.