Build a Hex Beam Antenna
The hex beam — formally the Broadband Hexagonal Beam — is arguably the most popular multi-band HF beam antenna among amateur radio operators with space or structural constraints that prevent a full-size Yagi or quad. Originally described by G3TXQ (Steve Hunt, SK), the hex beam delivers genuine 2-element directional performance across five or six HF bands simultaneously from a structure just 18 feet across that weighs under 10 pounds and requires only a light-duty rotator. Its secret is a bent wire geometry that achieves broadband matched performance on 20m through 6m from a single feedpoint on each band, with all bands sharing the same six fibreglass spreader arms radiating from a central hub. This guide covers G3TXQ hex beam theory, wire dimensions for all bands, hub construction, spreader arm installation, multi-band wire routing, feedpoint matching, and complete installation.
The G3TXQ Hex Beam Concept
The hex beam is a W-shaped bent dipole driven element paired with an inverted-U shaped reflector, all arranged in a hexagonal geometry supported by six fibreglass spreader arms. Steve Hunt G3TXQ refined earlier hex beam designs using NEC modelling to optimise the wire geometry for maximum gain, front-to-back ratio, and SWR bandwidth simultaneously — a combination that previous designs struggled to achieve:
Wire Geometry — Why the Bends Matter
The bent W-shape of the driven element is what gives the hex beam its unique combination of properties. Unlike a straight dipole or a full-wave loop, the bent geometry creates a specific current distribution and impedance that achieves broad bandwidth and near-50 Ω feedpoint impedance simultaneously:
Multi-Band Architecture — Five Bands, One Hub
The hex beam's most compelling feature is covering five or six bands simultaneously from one antenna. Each band has its own driven element wire and reflector wire, all sharing the six fibreglass spreader arms. The wires for different bands are attached at different distances along the spreader arms:
- 20m wires: attached nearest the spreader arm tips — the longest, outermost wires. The 20m driven element and reflector span the full width of the antenna (18 ft diameter).
- 17m wires: attached slightly closer to the hub than the 20m attachment points. Smaller loops nested inside the 20m geometry.
- 15m, 12m, 10m wires: progressively closer to the hub. The 10m wires are typically 6–7 ft from the hub — the innermost loops.
- 6m wires (optional): very close to the hub for a 6m pair — small but effective for 6m band openings.
- All bands same feedpoint: all driven element wires for all bands connect to the same feedpoint at the hub centre, connected in parallel to a single coax. Each band's driven element presents approximately 50 Ω at its resonant frequency, and presents a high impedance on other bands — the parallel combination is therefore dominated by whichever band is in use.
- No switching required: band changes require no relay or switch — the multi-band hex beam works on any band simply by transmitting on that frequency. The appropriate wire pair becomes active automatically.
Performance Expectations — What the Hex Beam Delivers
Setting realistic expectations for the hex beam avoids disappointment and helps operators understand when it is the right tool:
| Band | Freq (MHz) | Driven element total | Driven each side | Reflector total | Spreader arm length | Arm tip attachment |
|---|---|---|---|---|---|---|
| 20m | 14.15 | 32.8 ft (10.0 m) | 16.4 ft | 35.4 ft (10.8 m) | 9.5 ft (2.9 m) | At arm tip |
| 17m | 18.10 | 25.6 ft (7.8 m) | 12.8 ft | 27.6 ft (8.4 m) | 9.5 ft (2.9 m) | 7.4 ft from hub |
| 15m | 21.20 | 21.9 ft (6.7 m) | 10.9 ft | 23.6 ft (7.2 m) | 9.5 ft (2.9 m) | 6.3 ft from hub |
| 12m | 24.94 | 18.6 ft (5.7 m) | 9.3 ft | 20.1 ft (6.1 m) | 9.5 ft (2.9 m) | 5.4 ft from hub |
| 10m | 28.50 | 16.3 ft (5.0 m) | 8.1 ft | 17.6 ft (5.4 m) | 9.5 ft (2.9 m) | 4.7 ft from hub |
| 6m | 50.10 | 9.3 ft (2.8 m) | 4.6 ft | 10.0 ft (3.0 m) | 9.5 ft (2.9 m) | 2.7 ft from hub |
Note: dimensions are for the G3TXQ design. All six spreader arms are the same length (9.5 ft). The arm tip attachment distance varies per band — 20m attaches at the tip; 10m attaches at 4.7 ft from the hub on the same arm. Actual wire lengths should be verified against the G3TXQ calculator at g3txq.com before cutting.
Materials for a 5-band G3TXQ hex beam covering 20m, 17m, 15m, 12m, and 10m
Building the 5-Band G3TXQ Hex Beam
Build sequence: hub assembly → spreader arms → 20m wires first → test 20m SWR → add 17m wires → test → continue for each band → final assembly and raise. Testing one band at a time before adding the next makes troubleshooting straightforward — if 17m SWR is off, the 20m wires are not the cause.
Build or Source the Central Hub
The hub is the heart of the hex beam — it holds all six spreader arms at precise 60° intervals and provides the feedpoint terminal for all band wires. A poorly built hub that allows arms to shift angle degrades performance on all bands simultaneously. Commercial hex beam hubs are available from several suppliers and are the recommended option for most builders:
Install the Six Spreader Arms
Insert all six fibreglass spreader arms into the hub sockets. Verify each arm is at exactly 60° from its neighbours — use a protractor or digital angle gauge at the hub face. Even a 5° error in arm spacing noticeably degrades the front-to-back ratio on the affected band. Secure each arm with a hose clamp or set screw at the hub socket.
Label each arm 1 through 6 starting from the front direction and going clockwise. Arms 1 and 4 are the front-back axis of the antenna. Arms 2, 3, 5, and 6 are where the driven element and reflector wires attach. The driven element wire runs between arms 2 and 3; the reflector runs between arms 5, 4, and 1 (or 6, 1, and 4 depending on the design variant).
Cut and Install the 20m Wires First
Always install and test the 20m band first — it is the outermost band and its wires establish the reference geometry for all inner bands. Cut the 20m driven element wire slightly longer than the G3TXQ calculator value and the reflector wire at the calculated length. Do not cut to exact final length yet — leave 6 inches extra on the driven element for trimming:
Add Remaining Band Wires One Band at a Time
After confirming the 20m SWR, add the 17m wires at their attachment points on the spreader arms (7.4 ft from the hub). The 17m driven element follows the same W-shape and the 17m reflector follows the same inverted-U shape as the 20m wires, but at smaller scale. The 17m feedpoint wires connect to the same feedpoint terminals as the 20m wires — in parallel.
After installing each new band, sweep the NanoVNA across all previously installed bands to confirm the new wires have not disturbed the older bands' SWR. In a well-built hex beam, adding a new inner band has minimal effect on the outer bands because the inner wires present high impedance on the outer band frequencies. Proceed through 17m, 15m, 12m, and 10m in order from outermost to innermost:
Install Feedpoint Balun and Secure All Wires
With all five bands installed and SWR confirmed on each, install the 1:1 current choke balun at the hub feedpoint. The balun prevents common-mode current from flowing on the coax outer shield, which would cause RF in the shack and disturb the antenna's pattern. The hex beam's feedpoint is approximately 50 Ω on each band, so no impedance transformation is needed — only a current choke:
After the balun is installed, make a final full sweep from 13–30 MHz and document the SWR curve. This is your baseline measurement — any future change from this baseline indicates a wire movement, connection failure, or physical damage that needs investigation.
Mount on Mast and Raise
The hex beam mounts to the top of the mast via a plate bolted to the hub. Unlike a conventional beam, the hex beam has no boom — the hub is the structural centre and the mast connects directly to it. The antenna rotates with the mast using a rotator at the base. Because the hex beam is lightweight (8–12 lbs) and presents low wind load (wire elements offer minimal wind resistance compared to aluminium tubing), any medium-duty rotator handles it comfortably:
Verify Multi-Band Performance and Document
With the antenna at full height, perform a final NanoVNA sweep on all bands. Compare with the ground-level sweep — installed SWR is often slightly different from ground-level because the antenna's proximity to the earth changes the feedpoint impedance modestly. Both should show all bands within 2:1 SWR across the full amateur allocation:
Commercial Hex Beam Kits — When to Buy vs Build
Several manufacturers sell hex beam kits that include pre-cut wires, a fabricated hub, and spreader arms. The decision between a kit and a full homebrew build depends on available time and tools:
- Traffie Technology HexBeam: the most widely used commercial hex beam in North America. Pre-cut wire for each band, a well-engineered hub, and detailed instructions. Costs approximately $350–450. Highly recommended for operators who want a proven product without fabricating the hub.
- Spiderbeam hex beam: a European supplier with worldwide shipping. High-quality fibreglass spreader arms and wire. Similar price to Traffie. Their support resources and documentation are excellent.
- Homebrew advantage: a homebrew hex beam built from commercial fibreglass spreader arms, a 3D-printed or machined hub, and wire costs approximately $80–120 in materials. The main investment is time — approximately 15–20 hours for a careful first build. The G3TXQ website provides all necessary dimensions and the calculator is free.
- Recommendation: if you have access to a 3D printer and enjoy building, homebrew is rewarding and produces an antenna indistinguishable in performance from a commercial kit. If time is the constraint, a Traffie or Spiderbeam kit delivers a working antenna faster with minimal risk of dimensional errors.
Maintenance, Wire Replacement, and Long-Term Care
The hex beam is a wire antenna exposed to UV, wind, and thermal cycling — proper maintenance extends its life significantly:
- Wire life: #18 AWG copper wire with UV-resistant insulation lasts 5–10 years in most climates. Bare copper wire lasts longer mechanically but oxidises — the oxide layer adds slight resistance but does not significantly affect performance. Annual inspection of all wire connections at the hub and arm attachment points is recommended.
- Spreader arm replacement: fibreglass arms are the most mechanically stressed component — they experience bending loads from wire tension and wind. Cracks usually start at the hub socket or at wire attachment points where bending stress concentrates. Replace any arm that shows cracking — a failed arm drops the loop wire and detunes all bands.
- Wire re-tensioning: after the first winter season, re-tension all wires — they relax slightly after initial installation. Re-tension in late spring after thermal expansion has stabilised.
- SWR monitoring: take a NanoVNA sweep on all bands once per season. Any significant SWR shift from the baseline sweep indicates a wire movement or connection failure that needs investigation before it becomes a full failure.
- Hub weatherproofing: the hub centre feedpoint area must be fully weatherproofed. Apply self-amalgamating tape over all connections and reseal annually. Moisture at the feedpoint causes corrosion that shifts the resonance and increases loss.
| Symptom | Most likely cause | Diagnosis | Fix |
|---|---|---|---|
| All bands show high SWR simultaneously | Open circuit at feedpoint hub — coax disconnected or all driven element connections failed | Check DC continuity from coax centre to driven element feedpoint terminals; verify all bands' wires connect to feedpoint | Re-solder feedpoint connections; replace failed balun; verify coax connection at hub SO-239 |
| One band has high SWR, others normal | That band's driven element wire broken or disconnected at hub or arm attachment | Visually inspect that band's driven element wire along full length from hub to both arm tips | Repair wire break; re-secure wire at arm attachment point; verify wire connects to feedpoint on both sides of gap |
| SWR minimum shifted 100–200 kHz above target on one band | Driven element wire for that band is slightly too short | Measure actual wire length against G3TXQ calculator value for your arm length and wire gauge | Add small wire extensions (3–6 inches) to the driven element tips for that band; re-sweep after each addition |
| SWR minimum shifted below target frequency | Wire too long — common if wire was not cut to calculator spec | Measure driven element wire length; compare to calculator output | Trim 2–3 inches from driven element wire ends and re-measure; repeat until resonance is on frequency |
| Poor F/B ratio on all bands — antenna seems nearly bidirectional | Reflector wire wrong length; or reflector not a continuous closed wire on one or more bands | Verify reflector wire has no gap (should be continuous); measure reflector wire lengths | Confirm reflector wire is joined at both ends with no gap; adjust reflector length by adding or removing wire in 2-inch increments while monitoring F/B |
| SWR good on ground but shifts after raising to full height | Normal — proximity to earth changes feedpoint impedance; antenna coupling to nearby metal on mast | Compare SWR curves at ground vs installed height — 10–20 kHz shift is normal | Retrim driven element wire on affected bands at installed height; verify no metal within 3 ft of any wire |
| Antenna will not rotate smoothly — binding or jerking | Wire caught on mast or mast guy wire; or antenna off-balance causing rotator strain | Visually inspect rotation through full 360° with antenna visible; check for wire contact with mast | Re-dress wires away from mast; add plastic standoffs to keep wires clear; rebalance antenna on mast if visibly off-centre |
Is the hex beam as good as a 3-element Yagi?
No — a full-size optimised 3-element Yagi on a 24-ft boom produces approximately 7–8 dBd gain, compared to the hex beam's 5–6 dBd. The 3-element Yagi is 2–3 dB better, which is a meaningful difference in challenging conditions. However, a 3-element Yagi for 20m has 24-ft elements and requires a substantial tower, heavy-duty rotator, and significant structural investment. The hex beam provides approximately 80% of the Yagi's gain in a 10-lb package on a light mast. For a station limited to a 40-ft mast and a light-duty rotator, the hex beam is frequently the most competitive beam antenna practically achievable — and is far superior to a dipole at the same height.
Can I add 40m to the hex beam?
Adding 40m to a standard hex beam is difficult — the 40m wires would require 9.5-ft arm extensions beyond the existing tips, doubling the arm length and dramatically increasing wind load and weight. Some operators have built extended hex beams for 40m, but these are significantly larger structures requiring longer, stronger spreader arms and a heavier rotator. In practice, most hex beam operators use a separate 40m antenna — an inverted-V or dipole — alongside the hex beam, rather than attempting to add 40m to the hex beam structure.
Why does the hex beam use #18 AWG wire instead of heavier wire?
Lighter wire keeps the antenna's weight low — the complete 5-band hex beam in #18 AWG weighs approximately 8–10 lbs including hub and hardware. The same antenna in #14 AWG would weigh 15–18 lbs, requiring a heavier mast and rotator. The conductivity difference between #18 and #14 AWG at HF frequencies is small because of the skin effect — the effective conducting surface area does not change proportionally with wire cross-section at HF. The efficiency difference between #18 and #14 AWG in a hex beam is under 0.1 dB on any band — negligible for practical operation. #18 AWG is the correct choice for the hex beam.
Does the hex beam work on 6m?
Yes — adding a 6m wire pair to an existing hex beam is straightforward. The 6m wires attach at approximately 2.7 ft from the hub on each arm — well within the arm length. The 6m driven element is approximately 9.3 ft total and the reflector is about 10 ft. On 6m the hex beam provides approximately 6 dBd gain — excellent for 6m DX during sporadic-E and F2 propagation. Many operators add 6m to their existing 5-band hex beam as an upgrade, since the material cost is minimal (a few feet of wire) and the result is a high-performance 6m beam that is already on the rotator.
How does wind affect the hex beam?
The hex beam's wire construction gives it very low wind loading compared to aluminium element Yagis — the wires present a tiny cross-sectional area to the wind. In a 50 mph wind that would require a heavy-duty rotator and substantial tower for a 3-element Yagi, the hex beam experiences a fraction of the wind force. The main wind concern is that the wire elements vibrate and flutter in gusts, which shifts the resonance briefly during high-wind periods. This is generally not a problem for SSB or CW operation; digital mode operators sometimes notice brief SWR excursions during storm-level winds. Adding tension to the wires (they should be taut, not slack) reduces flutter significantly.
What is the typical SWR bandwidth on each band?
The G3TXQ hex beam is designed for broad SWR bandwidth — one of its distinguishing features. On 20m, the 2:1 SWR bandwidth covers the entire 20m amateur allocation (14.0–14.35 MHz, or 350 kHz) from a single fixed wire length. On 10m the bandwidth is even broader — the entire 10m band and beyond. On 17m, which has a narrow 100 kHz allocation, coverage is complete. This means no ATU is needed on any band during normal operation, and no adjustment is needed when moving within a band. The broad bandwidth is a direct result of the bent W-shaped driven element geometry that G3TXQ optimised.