Long‑Wire Antennas: Every Tree Is There to Help
End-Fed Long‑wire antennas (EFLW) remain one of the most capable RF radiators available. They are simple to construct, tolerant of installation imperfections, and capable of excellent multi‑band performance when used with a decent impedance match. For many hams, the real challenge isn’t getting the antenna right, it’s getting the wire up high into a tall tree.
A long wire typically spans ¼ λ (wavelength) and radiation resistance increases with wire length, improving efficiency. With a proper impedance match, an EFLW antenna supported by a tall tree can cover 80 through 10 m with satisfactory results.
The Slingshot Method
Getting a wire into a 50-foot tree is often the most demanding part. A reliable technique uses a slingshot, a fishing sinker, and a monofilament “messenger line” spooled onto a spin casting fishing reel. Spin casting reels have very low drag, and monofilament line has very little mass per metre. That means the sink has almost no drag other than air resistance.
A 15-gram lead sinker, tied to 20 lb test monofilament line provides about the right balance of mass and controllability. Lighter sinkers drift off target while heavier ones require too much force to launch them high. A wrist‑braced slingshot transfers enough kinetic energy for a clean, predictably high ballistic arc. Remember to always wear eye protection when using the slingshot and check down range is clear of buildings, cars, and people and it’s accessible. The lead sinker can be dangerous projectile when launched in this way. Safety first!
Choose a tall tree having branches with clear openings and aim the sling shot so the sinker passes over and drops on the far side of a high branch. It might take a few attempts, and a sinker painted a bright colour is helpful when searching for it in long grass or weeds. Once the fishing line is draped over a suitably high branch, locate and remove the sinker, and attach the fishing line to a light paracord or polypropene line. Using the spin casting reel, retrieve the fishing line and this will pull the paracord line up and over the tree limb. This paracord becomes the support line for the EFLW. Attach the antenna wire to the paracord and pull the antenna up and toward the tree limb until it’s about a metre away from branches and leaves.
Assuming you’re reasonably strong young adult, you should be able to reach a 20-metre-high branch about 30 metres away without too much trouble. The higher the better.
RF Feedpoint
End‑fed long wires present relatively high impedances of about 800–1500 Ω depending on the height of the wire and its angle of elevation. A 9:1 impedance transformer, often referred to as an Un-Un, reduces the impedance “seen” by the transceiver to something useable. At low power levels typically used during portable operations, the standing wave ratio (SWR) of the antenna systems is not an overriding concern.
RF Counterpoise
A critical but often overlooked element is the RF counterpoise or current return path. An EFLW antenna must work against something and if no intentional counterpoise is provided, then RF return current will find a “path of least resistance” using whatever conductive path is available. A length of wire, or a radial of wires, all cut to about the same length as the EFLW make an effective RF counterpoise. Those wires need to terminate at the conductive shield of the coax connected to the SO-239 jack on the transceiver while the EFLW connects to the centre conductor.
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73 de VE7DQS
Last Updated on 2026-09-03 by Joannadanna