Mounting a 80m Doublet on a 16m Pole with 16m 600Ω open-wire feedline

Antenna Type: Doublet (2x40m legs, 80m total span)
Center Support Height: 16 meters (carbon mast)
Feedline: 16 meters of 600Ω open-wire feedline
Recommended Configuration: Inverted-V

Inverted-V Geometry

  • Feedpoint height: 16m (top of center carbon mast)
  • End height: Ideally between 2 to 5 meters above ground
  • Leg angle (apex angle):
    • Optimal: 120°–140° between the legs (60°–70° from vertical per leg)
    • Minimum recommended: 90° (anything tighter reduces efficiency and bandwidth)
    • Optional 35m rope extension available: Helps achieve the ideal leg angle, anchoring is on ground level.

Open-wire Routing

  • First 3–4 meters: Drop vertically from feedpoint to reduce imbalance
  • After vertical drop: Gentle curve or slope toward tuner location
  • Keep open-wire:
    • At least 10–15 cm from any conductive surface
    • Away from metal poles, gutters, fences, or walls
    • Free-hanging or on non-metallic standoffs if necessary

End Anchoring

  • Anchor distance: ~38m out from the base of the center pole
  • Use: Non-conductive rope, UV-resistant if outdoors
  • Anchoring point height: The higher, the better (4m or more is fine)
  • Optional 35m rope extension available: Helps achieve the ideal leg angle, anchoring is on ground level.

Performance Notes

  • Radiation pattern: Broadside, omnidirectional lobes on higher bands
  • Usable bands: Usable bands: 160m (resonant, good with proper feed and tuner), 80m to 10m (very efficient with a wide-range tuner)
  • Tuner location options:
    • Best: 1:1 current balun + remote tuner at open-wire transition
    • Alternative: 1:1 balun + indoor tuner (coax feedline can lead to higher losses !)

You’re using a full-sized 160m doublet, so it’s not “less efficient” — it’s perfectly efficient if the open-wire is tuned correctly.

Typical impedance at the base can range from 30Ω to 2000Ω depending on band and length. Use a tuner that handles high impedance and reactance if placed indoors. (use short length of coax to minimise losses)

Open-wire feedline ensures minimal loss even with mismatch. A remote wide-range tuner (or Z-match) at the base of the open-wire, right after a 1:1 current balun, is highly recommended. This setup minimizes feedline loss and ensures efficient multi-band operation across 160m to 10m. (read more)

Written by Joeri Van Dooren, ON6URE – RF, electronics and software engineer, complex platform and antenna designer. Founder of RF.Guru. An expert in active and passive antennas, high-power RF transformers, and custom RF solutions, he has also engineered telecom and broadcast hardware, including set-top boxes, transcoders, and E1/T1 switchboards. His expertise spans high-power RF, embedded systems, digital signal processing, and complex software platforms, driving innovation in both amateur and professional communications industries.