Why “Best” Doesn’t Exist

Comparing antennas without naming the job is like comparing shoes without saying whether you are going to a wedding, climbing a mountain or sprinting on a track. It is like asking for the sharpest camera lens without saying whether you photograph wildlife at distance, portraits in a dark room or landscapes at sunrise. It is like ranking tyres without mentioning snow, wet motorway, gravel or racetrack.

That is not a way to avoid a recommendation. It is the reason a recommendation can become defensible. The word best needs a declared objective, and the objective has to survive the real constraints of the site and the complete RF system.

“Best” Is an Objective Under Constraints

There can be a best option for a stated job. There is no context-free best antenna. An engineering choice has at least three parts:

• Objective: the result to improve—received SNR on chosen paths, realized gain over an angular sector, coverage probability, matched bandwidth, efficiency, setup time or another measurable outcome.
• Constraints: bands, space, height, supports, wind loading, power and duty cycle, exposure boundary, current authorization, cost, maintenance and acceptable complexity.
• Evidence: calculations, models and measurements with conditions and uncertainty stated.

If the objective has several competing metrics, the word best also needs priorities. Maximum low-angle field, wide all-direction coverage, low local-noise pickup and minimum physical size may not point to the same design. A single weighted score can be useful, but it should not hide which trade-off produced the winner.

Gain Is Not One Kind of Improvement

The active IEEE 145-2025 antenna terminology standard keeps directivity, gain and realized gain distinct. Directivity describes how radiation is distributed by direction. Gain includes antenna efficiency. Realized gain also includes input mismatch under the applicable definition.

Higher gain can therefore come from greater directivity, better efficiency or both. When directivity increases, radiation is redistributed into some directions at the expense of others. That is useful only when those directions overlap the paths or coverage region that matter. When efficiency improves, less accepted power is dissipated, but the pattern may remain similar. Quoting one peak value without the 3D pattern, polarization, frequency, reference and test conditions is not enough to choose an antenna.

dBi and dBd are different reference conventions, and peak gain is not average coverage. Compare like with like and inspect the angular region that serves the objective—not merely the largest number in a table.

Bandwidth Is a Set of Performance Limits

“Covers 3–30 MHz” is not a complete performance statement. An antenna can meet one SWR limit across a range while gain, efficiency, pattern, polarization, common-mode current or component temperature changes materially. Another design can be narrow in impedance bandwidth but excellent over the only operating segment that matters.

Define usable bandwidth through the relevant limits: maximum reflection, minimum realized gain in the desired sector, pattern stability, efficiency, voltage/current margin, linearity, temperature rise or receive SNR. State frequency resolution and the installed configuration. Without that, two bandwidth numbers may describe different tests.

Polarization Belongs to the Link

A transmitting antenna does not own the received result. Coupling depends on both antennas and on propagation. A polarization mismatch can reduce received power, but the value depends on the actual polarization states rather than the labels “vertical” and “horizontal.” Reflections, terrain and ionospheric propagation can change polarization along the path.

The in-force ITU-R P.341 transmission-loss framework explicitly includes antenna loss, feed-line loss, impedance adjustment and polarization among the link factors. That is why a polarization comparison must state both ends, path and propagation conditions. One orientation is not universally superior.

The Feed System Is Part of the Result

Transmitter output power is not necessarily power accepted by the radiator. Connector loss, feed-line attenuation, mismatch, matching-network loss and unintended current on the feed-line exterior all affect the installed system. Loss and mismatch are frequency-, temperature- and configuration-dependent.

For a fair comparison, choose a common reference plane and account for the path from that plane to each antenna. If two candidates require different matching networks or feed lines, measure or estimate those losses rather than pretending they are identical. Record accepted power when the claim is about antenna gain or efficiency; record transmitter power when the claim is about the complete station as operated.

Common-mode current can also change pattern, local-noise coupling and station behavior. Do not assume that one choke position solves every candidate. The ARRL common-mode workflow measures exterior-coax current, installs the chosen suppression and measures again across the required frequencies.

The Site Can Change the Winner

Height in wavelengths, ground conductivity and permittivity, terrain, nearby metal, buildings, vegetation, supports and other antennas can alter current distribution and the resulting pattern. The current ITU-R BS.705-2 HF antenna recommendation treats ground, vertical earth systems, surrounding structures and measurement conditions as explicit variables. A catalogue pattern is not automatically the installed pattern.

The receive objective is usually SNR or intelligibility, not raw signal level. A lower-gain antenna can win at one site if its pattern or polarization rejects more local noise or interference in the relevant direction. A high-output active system can lose if it overloads the receiver. Conversely, reducing both signal and noise by the same amount is not an SNR improvement.

ITU-R P.372-17 separates atmospheric, galactic and man-made radio-noise contributions and treats their variability statistically. “My noise floor dropped” is therefore not enough. Record wanted signal, noise in the same bandwidth and receiver state.

A Fair A/B Test Starts With the Claim

Before connecting a switch, write the claim the test is meant to support. “Better” is not a measurand. Examples that can be measured include:

• realized gain in a declared direction and polarization;
• received SNR distribution over selected stations or paths;
• matched bandwidth under a stated SWR limit;
• radiation efficiency under a named method;
• exterior-feed-line current across the operating range;
• temperature rise and match drift at a declared waveform and duty cycle; or
• deployment time, repeatability and mechanical survival under stated conditions.

Then control what can distort that claim:

• frequency, bandwidth, modulation, transmitter and receiver settings;
• accepted power or a fully stated station-power reference;
• height, orientation, polarization, feed-line route and nearby structures;
• matching and feed losses at the test frequency;
• switch and connector loss;
• time between observations and propagation variability;
• receiver AGC, attenuation, preamplifier state and overload;
• background noise, weather and site changes; and
• measurement repeatability and uncertainty.

If two antennas cannot occupy the same position simultaneously, swap their positions and repeat. If they share one mast in sequence, switch rapidly enough to reduce propagation drift and repeat over multiple periods. Use several directions when the objective is coverage. One distant report proves performance on that path at that time, not a universal gain ranking.

A calibrated antenna range is the right tool for gain and pattern claims. IEEE 149-2021 sets out antenna-measurement practice, and NIST’s measurement guidance requires uncertainty sources to be identified and combined. On-air A/B work is valuable, but it measures the complete antennas-plus-sites-plus-propagation experiment.

The Objective Can Be Written in One Sentence

That sentence prevents the usual category error. “Maximum low-angle realized gain on 20 metres from this 12 m support” is a different problem from “most reliable 80–10 m holiday antenna in one carry-on bag” or “highest receive SNR in one urban noise field.” The winner can legitimately change because the question changed.

Clear Constraints Make Better Recommendations

Before asking for a model name or topology, answer the questions that decide the engineering:

• Which exact frequencies and emission bandwidths matter?
• Which paths, distances, directions and polarizations matter?
• Is the priority transmit field, receive SNR, coverage, portability or a defined combination?
• What height, footprint, supports and feed-line routes are actually available?
• What ground, terrain, buildings, metal and local noise surround the installation?
• What power, waveform, duty cycle and thermal margin must the system handle?
• Which authorization, exposure, property and mechanical limits apply?
• How will the result be measured, and what difference would be meaningful relative to uncertainty?

The Lack of One Winner Is the Useful Part

Antennas are honest about trade-offs. They punish vague objectives and reward precise ones. The shoes, lens or tyres do not become worse because they are wrong for another job; they become understandable once the job is stated.

The best antenna is not the one with the nicest number on the box. It is the one with the strongest evidence for your declared objective, at your site, inside your constraints.

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