Design an End-Fed Half-Wave (EFHW) or an End-Fed Random-Length (EFRL) antenna, in inverted-L, or inverted-Vee, or sloper form, using a single main support. The EFHW antenna is designed for one principal amateur HF band, usually 80 meters or 40 meters, but typically displays VSWR minima on several higher, harmonically-related, bands and can therefore be a good multi-band antenna. Being an end-fed antenna with a high feed-point impedance and high feed-point voltage, it is used with an unun - typically 49:1, 64:1, or higher - to bring the impedance down to a range which can easily be handled by an antenna matching unit. Read more...
EFHW or EFRL antenna? » » »
Length, feet |
Length, meters |
Bands* |
29.0 | 8.84 | 30m - 10m |
35.5 | 10.82 | 40m - 10m |
41.0 | 12.50 | 40m - 10m |
52.0 | 15.85 | 60m - 10m |
58.0 | 17.68 | 60m - 10m |
71.0 | 21.64 | 80m - 10m |
107.0 | 32.61 | 80m - 10m |
119.0 | 36.27 | 80m - 10m |
135.0 | 41.15 | 160m - 10m |
148.0 | 45.11 | 160m - 10m |
203.0 | 61.87 | 160m - 10m |
347.0 | 105.77 | 160m - 10m |
407.0 | 124.05 | 160m - 10m |
423.0 | 128.93 | 160m - 10m |
*
Some bands may not be available
or tunable in your setup |
Get started » » »
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Set antenna color: |
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EFHW (End-Fed Half-Wave) antenna designer
Antenna feed-point: ⬥
Inductance load: ●
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Here you can generate plots of radiation patterns, VSWR chart, antenna currents diagram and Smith chart for your antenna over a
choice of ground types. By changing the physical dimensions of the antenna, and refreshing these plots, you can learn a lot about
how such antennas will perform in the field.
Please note that
radiation patterns are here modelled over flat ground -
when the antenna is erected on a hill-top or mountain summit, the surrounding sloping ground will generally cause angles in
the elevation radiation pattern to be lowered in the direction of the
slope: the steeper the slope, the lower the effective elevation take-off angle will be, and the better the chances of making
long-distance contacts.
Read more...
Choose ground type of
land in the vicinity of the antenna: |
Conductivity:
S/m
Dielectric const.:
F/m
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View radiation patterns: |
Set elevation angle for azimuth plot:
Set azimuth angle for elevation plot: |
Radiation patterns for: |
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View VSWR chart: | Check on: From: To: |
Display impedance curves: | Using unun |
Impedance curves scales: | |
Effect of coax on VSWR: |
Coax length:
Type:
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View currents diagram: | |
View Smith chart: |
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Antenna gains at 0° elevation: |
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Antenna impedance: | |
Frequency range: | |