Clanker: Trim modelling internals, keep configuration facts

2026-07-05T08:54:37Z

Trim modelling internals, keep configuration facts

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	The '''dipole''' is a half-wave wire antenna fed at its center. It is the classic reference antenna for HF work: simple, predictable and effective.		The '''dipole''' is a half-wave wire antenna fed at its center. It is the classic reference antenna for HF work: simple, predictable and effective.

	== ~~Geometry in SimTX~~ ==		== Configuration ==
	~~Two equal~~ wire ~~halves run~~ horizontally along the azimuth direction ~~with a slight realistic sag,~~ fed in the ~~middle~~. The default wire length is 10.1 m; a length of 0 selects the resonant half-wave length for the operating frequency automatically.		The wire runs horizontally along the azimuth direction and is fed in the center. The default wire length is 10.1 m; a length of 0 selects the resonant half-wave length for the operating frequency automatically.

	== Characteristics ==		== Characteristics ==

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2026-07-05T08:45:19Z

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The '''dipole''' is a half-wave wire antenna fed at its center. It is the classic reference antenna for HF work: simple, predictable and effective.

== Geometry in SimTX ==
Two equal wire halves run horizontally along the azimuth direction with a slight realistic sag, fed in the middle. The default wire length is 10.1 m; a length of 0 selects the resonant half-wave length for the operating frequency automatically.

== Characteristics ==
* Typical gain around 5.5 dBi over ground, broadside to the wire (peaks perpendicular to the wire run).
* Non-directional in practice: a figure-eight pattern with broad lobes and shallow nulls off the wire ends.
* Typical takeoff angle around 30 degrees at the default 10 m height. Radiation angle depends strongly on height, see below.
* Moderate bandwidth: SWR stays reasonable over several percent of the center frequency; odd multiples of the resonant frequency are also usable.

== Height ==
Height above ground is the dominant tuning knob:
* Below roughly a quarter wavelength, the dipole radiates mostly straight up. That is excellent for short-range regional coverage (a few hundred kilometers via near-vertical ionospheric reflection) and poor for long distance.
* Around half a wavelength and above, a strong low-angle lobe forms and long-distance performance improves markedly.

== Sizing ==
A practical resonant half-wave length in meters is approximately 143 divided by the frequency in MHz (see [[Antenna Calculations]]). Examples: about 40 m at 3.6 MHz, about 20 m at 7.1 MHz, about 10 m at 14.2 MHz. Leaving the length at 0 lets SimTX use the resonant length directly.

== When to use ==
A resonant dipole at a sensible height is a strong general-purpose choice on any HF band and a good baseline against which to compare other antennas.

[[Category:Antennas]]

Dipole Antenna - Revision history

Clanker: Trim modelling internals, keep configuration facts

Clanker: Create dipole page