When it comes to ham radio, choosing the right antenna is one of the most important decisions an operator will make. There are dozens, if not hundreds, of varieties: Yagis, wire antennas, full-wave loops, verticals, and more.
Each has its own advantages and disadvantages. The choice depends on factors like frequency bands, operating conditions, space, efficiency, and desired performance.
Will you choose resonant or non-resonant antennas? Let’s explore their characteristics, and the pros and cons of each.
Resonant Antennas
A resonant antenna is designed to operate at or near a specific frequency or a set of frequencies. For many ham radio operators (especially newbies) the simplicity of resonant antennas is an attractive feature. A half-wave dipole antenna is relatively straightforward to build and adjust. These antennas also typically don’t require additional components, like matching networks, to work efficiently.
Resonant antennas include monoband dipoles, fan and parallel dipoles, end-fed half-waves (EFHW), monoband and trapped verticals, single band, and trapped multiband Yagis. You can build resonance into these antennas using traps, linear loading, stubs, or a radiator specifically tuned for a particular band. With these antennas, resonance occurs only in narrow parts of the spectrum on the lower HF bands, such as 160, 80, and 60 meters, but widens on bands above 40 meters for nearly full coverage.
At the resonant frequency, the antenna presents a balanced load (generally 50 ohms) with minimal reactance, giving optimal performance. The antenna efficiently radiates electromagnetic waves and has a natural impedance match with the transmission line, reducing power loss and ensuring that maximum power is radiated.
Advantages of Resonant Antennas
- They’re generally more efficient because their design is optimized for a particular frequency. Resonant antennas reduce power losses that may occur when using a non-resonant antenna.
- Dipoles and verticals generally have predictable radiation patterns, which is good for ham operators who want consistent performance. These antennas are excellent for reaching specific distances or contacts, especially for HF or VHF.
- These antennas naturally match the impedance of the transmission line, often 50 ohms, without the need for additional matching networks. This means better power transfer and less signal loss.
- Since resonant antennas are matched to their frequency, they typically have a lower SWR, which minimizes the amount of reflected power. This factor is important for protecting your transmitter.
Disadvantages of Resonant Antennas
- One of the primary drawbacks is their limited bandwidth. They work best at a specific frequency or a limited range of frequencies. For ham radio operators, this could mean needing to switch antennas for different bands or adjusting antenna lengths for optimal performance at different frequencies.
- Antennas can be large and cumbersome, particularly those designed for lower frequencies such as 160 and 80 meters. Size can become a significant challenge for operators with limited space or those in urban environments. For example, a half-wave dipole for 80 meters (3.5 MHz) is 130 feet long, which may be impractical for some hams.
- If you’re a ham operator who wants to work across multiple bands, you may need multiple resonant antennas or require frequent switching of antenna configurations.
Non-Resonant Antennas
A non-resonant antenna doesn’t rely on a specific frequency or wavelength for optimal operation. It is designed to operate over a broad range of frequencies. Non-resonant antennas include configurations like off-center fed dipoles, non-trapped multiband verticals, long wires, doublets, and compromise antennas.
Since they do not normally present an optimal impedance at any given frequency, non-resonant antennas typically require a wide-range antenna tuning unit (ATU) or balun/unun to match their impedance to the transmission line. Using either or both of these ensures maximum power is transferred to the antenna, even when it’s not resonant at the operating frequency.
Advantages of Non-Resonant Antennas
- The most significant advantage of non-resonant antennas is their ability to operate over a wide frequency range with the help of an antenna tuner and/or balun/unun. This is particularly valuable for ham operators who want to use a single antenna for multiple bands, such as 80 meters, 40 meters, 20 meters, and beyond.
- While some non-resonant antennas, like random wire antennas, may still require a reasonable amount of space, many designs (e.g., shortened vertical or off-center-fed dipole) can be more compact than their resonant counterparts, making them ideal for use in limited space.
- Non-resonant antennas allow hams to work across multiple bands without making significant adjustments. This can be advantageous for hams who want to communicate across different frequencies without the hassle of switching antennas.
- For ham operators limited by space or HOA regulations, non-resonant antennas like random wires or shortened verticals are more feasible. They can be mounted in less-than-ideal locations (such as in an attic or on a balcony) and still provide usable performance.
Disadvantages of Non-Resonant Antennas
- Non-resonant antennas generally have an impedance mismatch with the transmission line across the frequency spectrum. This can lead to higher SWR, causing power loss and potential damage to the transmitter. An antenna tuner can mitigate this, but it adds extra equipment to the setup.
- Since non-resonant antennas aren’t specifically optimized for a single frequency, they are often less efficient than resonant antennas. Power losses due to impedance mismatches can reduce overall performance.
- Non-resonant antennas, especially when combined with an antenna tuner, can be more complex to set up. Operators need to periodically check and adjust their antenna tuner for best match.
- Non-resonant antennas may not produce a radiation pattern that is as predictable or optimal as resonant antennas. This can be a disadvantage in situations where consistent, directional radiation is important.
Which Antenna is Better for Ham Radio Communications?
When you look at the resonant antenna information, it may seem like the best choice. They’re relatively easy to build and tune, and a matching network or ATU isn’t always needed (except for 160 and 80 meters). They’re also a known quantity with somewhere near a 50-ohm impedance and a reputation for efficiency.
Resonant antennas are ideal for operators who primarily work on specific bands and want the highest efficiency and simplicity. They are perfect for those with the space to install large antennas and are mainly concerned with performance on particular frequencies. If you operate primarily on a single band or a few bands, resonant antennas are likely the best choice.
I’ll have to admit, most of the antennas at my QTH fit into the resonant category. There’s a good mix of verticals, multiband dipoles, and three Yagis. All of them fit on my lot (barely), and I’ve made sure they’re isolated from each other as much as possible. I like to work DX and participate in a few contests.
Non-resonant antennas, on the other hand, are better suited for operators who need versatility and the ability to operate on multiple bands without constantly adjusting their antenna setup. They are helpful for ham operators with limited space or those who frequently work on different frequencies. However, these antennas require additional components such as an antenna tuner and may be less efficient than resonant designs.
Admittedly, there’s no magic antenna solution that does everything well. When looking at the advantages and disadvantages of resonant and non-resonant, it’s clear that the antenna application, bands of operation, and available space should be the primary considerations.
Even the humble half-wave dipole can be a DX magnet when properly tuned and placed as high above ground as possible. For those wary of traps and loading coils, the fan dipole is a straightforward way to add bands with a single feedline connection and keep them resonant.
Space-Challenged Hams
If you don’t have much antenna space on your lot, there are some solutions involving minimal compromise. Here’s where a combination of resonant and non-resonant antennas can get you operating on more bands. There’s no reason why you can’t choose the best of both worlds.
Got 33 feet of space? A 20m resonant antenna will get you on this active DX band. If you want to add the other bands through 6m, convert it to a fan dipole or bend it into a cobweb antenna, adding a 1:4 matching transformer. That will reduce the size to about 9 x 9 feet.
Modify a Rybakov vertical non-resonant antenna into a 53-foot inverted-L—26 feet vertical, 27 feet horizontal—and you’ll have 80-6m coverage. Or put up a Hustler 5BTV resonant trap vertical that’s 25 feet tall and covers five HF bands 80-10m. Both will require radials, but many shorter ones will work nearly as well as a few longer ones.
For HOA compliance, you might be limited to attic antennas or ones that go around the outside edges of the roof. An HF loop antenna tacked up around the perimeter of the attic and attached to a tuner can provide an acceptable match. A Par EndFedz EFHW is a resonant alternative for multiband operation that can also fit inside an attic or outdoors. Models include the EF-40-10-KW, 8010-JRKW (below) 74-foot loaded version, and the tunable EF-QUAD.
POTA & Portable
If you’re doing Parks on the Air® (POTA) activations or operating portable, non-resonant antennas may be the best choice. They don’t require much space, they’re lightweight, and will assemble quickly so you can maximize your air time.
The Rybakov antenna has become popular among the POTA/portable crowd. It’s a 25-foot vertical wire matched with a 4:1 unun. It includes a few radials that can be hung from a tree or supported by a telescoping fiberglass pole. The nice thing about this antenna is that you can use it on many bands, typically 40-10 meters. The bandwidth on each band is pretty good, though you may find a tuner helpful. Once you have tuned in the middle of a particular band, you don’t have to tune again when you work near the band’s edges.
EFHWs are also favorites for POTA/portable use, but these antennas are a mixed bag. They have either a 49:1 or 64:1 unun for matching. The 40m version is resonant on harmonics but requires a tuner for 30, 17, and 12m. The best feature is their size—they’ll fit in a coat pocket or can be easily tucked into your equipment bag.
End-fed long wire antennas use a 9:1 unun with “magic” antenna lengths that provide optimal performance across a wide range of frequencies—29, 35.5, 41, 58, 71, and 84 feet are the recommended numbers. The 9:1 balun converts impedance from 450-700 ohms to help match the 50-ohm coax feedline. A tuner may be required on some bands. Long wires are perennially popular antennas for field and portable use.
Working DX & Contests
If you’ve driven on Interstate 80 near the Ohio/Pennsylvania border, you may have seen the K3LR contest station antenna farm. Here, you’ll find a variety of Yagis, verticals, and a unique four-element 160-meter antenna built around a 190-foot tower. To the best of my knowledge, all are resonant antennas.
Working DX during band openings or DXpeditions is awesome, especially with resonant monoband and multiband Yagis. Directionality and a few dBs of gain make these resonant antennas a good choice for busting pileups and accumulating countries for your DXCC award.
Best Choice(s)
The entire antenna system as a whole needs to provide a reasonable match between the transceiver and the antenna. As long as the losses in the antenna and feedline are not too high, matching can be done anywhere in the antenna system. It makes no practical difference whether the radiator by itself is resonant or not.
Usually, the best choice is the one that works well for you and your situation. For some, the best antenna choice could be a hybrid solution, such as a multiband resonant antenna and a non-resonant antenna connected to a tuner, providing the best of both worlds. Ultimately, it’s about balancing performance, efficiency, size, and flexibility based on your unique operating conditions.
