This is the construction-height companion to Part 1. The goal is a home-station fan vertical for 20, 17, 15, 12, and 10 meters, using four elevated radials per band. That makes twenty radial wires in total: more ambitious than a four-wire portable setup, but still practical enough to plan without needing a civil-engineering permit for the backyard.
Suggested starting geometry
Set the feed point and common radial hub 8 to 10 feet above ground. About 9 feet is a useful middle target. Keep the radial ends nearly level with the hub. A gentle downward slope is acceptable, but after normal sag the ends should ideally stay at least 7 to 8 feet above ground—and safely beyond anyone’s ordinary reach.
An approximately 26-foot fiberglass mast gives the longest, 20-meter driven wire enough room. Starting from a 9-foot hub, a 20-meter element around 16.5 to 17 feet reaches near the mast top. The shorter 17-, 15-, 12-, and 10-meter elements can share the same support as a vertical fan.
Plan the radial fan before cutting wire
Use four radial wires for each of the five bands. Attach every one to the common elevated hub, spread them evenly, and keep matching pairs opposite one another where the site allows. The aim is not a perfect compass rose worthy of a museum; it is similar height, similar sag, similar surroundings, and no one radial routed around a suspiciously large metal object while its partner lives in open air.
| Band | Four radial starting lengths | Driven-element starting length |
|---|---|---|
| 20 m | About 16.8 ft each | About 16.5–17 ft |
| 17 m | About 13.4 ft each | About 13–13.5 ft |
| 15 m | About 11.3 ft each | About 11–11.5 ft |
| 12 m | About 9.8 ft each | About 9.5–10 ft |
| 10 m | About 8.4 ft each | About 8–8.5 ft |
Cut every wire a little long at first and label it before installation. Radial and driven-element lengths may begin in the same neighborhood, but they are not promised to finish equal. Tune the driven elements one band at a time with actual SWR and impedance measurements; keep the radial fan as symmetrical as possible while doing so.
A sensible construction sequence
- Install and guy a stable, nonconductive 26-foot fiberglass mast according to its manufacturer’s instructions.
- Mount an insulated feed point and radial hub around 9 feet high.
- Install the five driven wires, with the 20-meter element establishing the required mast height.
- Cut, label, and attach the five four-radial sets to the same hub.
- Support the radial ends so their heights and sag are comparable; use nonconductive supports where practical.
- Install a capable common-mode choke at the hub so the coax shield does not audition as an unwanted twenty-first radial.
- Measure SWR and feed impedance on every band, then make small, documented changes. If results wander, inspect symmetry, nearby conductors, and feed-line routing before blaming the radio.
Safety is part of the antenna design
- RF-bearing wires: Elevated radial wires can carry significant RF voltage. Keep the entire fan inaccessible to people, children, pets, and routine foot traffic—not merely the hub.
- Nearby conductors: Keep wires clear of roofs, gutters, fences, towers, utility wiring, vehicles, and other conductive structures. They can detune the system and may become energized.
- Lightning and station grounding: A radial system is not a lightning-protection system. Provide appropriate station bonding, surge protection, and disconnect practices for the site; disconnect before working on the antenna.
- RF exposure and interference: Before higher-power operation, evaluate RF exposure and check for interference to household electronics. A good match alone does not establish either safety or compliance.
- Animals and breakaway behavior: Use sensible, nonconductive end supports and plan for a wire to release rather than injure an animal or pull down the mast if a deer—or a very determined dog—snags a radial. Any breakaway arrangement still needs to leave no reachable energized wire behind.
Why this height range
The useful electrical improvement starts when radial wires move away from the ground; an extreme height is not required. Elevated radial systems are often placed in the 4- to 10-foot range. This guide favors 8 to 10 feet because it provides meaningful separation from the soil while offering a more realistic margin for wires that must remain out of reach. It reduces ground interaction and coupling; it does not make them disappear.
Research on optimized systems supports the value of additional, well-balanced radials, but this design should not be read as a claim that 10–12 radials per band is a universal minimum. Four radials per band is a practical multiband starting configuration. The final result is governed by the installed geometry and the particular yard, which will certainly have opinions.
Currently Still Under Construction as a Multiband System
Multiband tuning is complicated enough before adding a fan of elevated return wires, and leaving this many wires suspended full-time would be both impractical and unsafe. This is therefore a multi-month installation and test program, not a weekend project with a cheerful “close enough” at the end.
For testing, each tuned radial set will be installed deliberately, measured in the actual configuration, and removed when it is not in use so the yard does not become a permanent elevated-wire obstacle course. Temporary removal reduces an ongoing exposure, but it does not eliminate the hazards while a set is being installed, energized, lowered, or handled. No testing should take place near people, animals, vehicles, or power lines, and every conductor still has to remain out of reach.
This work is extremely time-intensive: set up, measure, document, compare, remove, repeat, and try not to confuse one labeled wire with another. Results will eventually be posted—perhaps within a year, or ten—once enough real measurements exist to say something useful rather than merely dramatic.
Research basis
This guide draws on Rudy Severns, N6LF, Experimental Determination of Ground System Performance for HF Verticals, Part 3: Comparisons Between Ground Surface and Elevated Radials, QEX, March/April 2009; Severns, Ground Systems for Multiband Verticals, QEX, November/December 2009; and A Closer Look at Vertical Antennas With Elevated Ground Systems, QEX, March/April and May/June 2012. Those studies support elevated, resonant, and symmetrical radial systems while emphasizing that local soil, installation geometry, and nearby conductors determine the final tune and performance.
These citations are representative, not exhaustive. More technical references are available online through paid access and paywalled archives, and the research base is considerably larger than can reasonably fit here. A few additional copies are not listed because only pieces remained after the dog ate them. For the record, the dog is not actually mine.