Canvey Island, Essex, England
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144MHz LFA Yagis

Low Noise LFA Yagis designed by G0KSC free to build for personal use.

G0KSC Twin-Boom Quads
Custom low-noise dish feeds
Custom low-noise dish feeds
G0KSC Custom Dish Feeds

Above installation @ HB9Q

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A 10el 12.5 Ohm 50MHz Optimised Wideband Low impedance (OWL) Yagi

Premium commercial versions of this antenna at Innovantennas

The OWL by G0KSC provides the benefits of both OWA (Optimised wideband Array) 50 Ohm antennas with those of traditional low impedance antennas. More information on the OWL can be found in the CONSTRUCTION menu above.

Do not look at the gain figure of this antenna and compare with other 10 element 50MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With almost 14.69dBi and a boom less than 15.1M long, this antenna will be a winner for field days and the rural Ham radio operator. 


  • Special attention should be taken in ensuring the element spacing and sizes are absolutley correct upon a 12.5 Ohm Yagi
  • If SWR is not perfect, D1 may also need to be adjusted. An analyser is reccomended for use when finalising 12.5 Ohm OWL Yagis
  • Visit 'Making the OWL Match' for more information on the recommended matching methods
  • Please add 2mm to each element to allow for insulator correction if using G0KSC Insulators. Other insulators may require different correction. Email me for more information

An 8el OWL installed at ZL1RS

Performance UK/USA Version

Forward Gain:                           14.69dBi at 50.250MHz

Front to Back Ratio:              22.28dBi at 50.250MHz

Peak Gain:                                 14.7dBi

Peak F/B:                                22.32dB

Bandwidth:                               500KHZ below 1.2:1

Build Dimensions for UK/USA Version

Element  -  Spacing (m) - Half element Length   Element Notes

Reflector               0                    1.484             12.7mm 1/2 inch Diameter tube

DE                       .329               1.438              12.7mm  1/2 inch tube

D1                     1.055               1.3915            12.7mm 1/2 inch Diameter tube

D2                     2.314               1.366              12.7mm 1/2 inch Diameter tube

D3                     4.054               1.3365            12.7mm 1/2 inch Diameter tube

D4                     6.081               1.3155            12.7mm 1/2 inch Diameter tube

D5                     8.277               1.301              12.7mm 1/2 inch Diameter tube

D6                     10.555             1.2845             12.7mm 1/2 inch Diameter tube

D7                     13.095             1.2605             12.7mm 1/2 inch Diameter tube

D8                     15.161             1.2745             12.7mm 1/2 inch Diameter tube

Build Dimensions for European Version

Element           Spacing  Half element            Element Notes

Reflector               0                1.484          12mm Diameter tube

DE                       .329           1.438           12mm Diameter tube

D1                     1.055           1.3915          12mm Diameter tube

D2                     2.314           1.366            12mm Diameter tube

D3                     4.054           1.3365           12mm Diameter tube

D4                     6.081           1.3155          12mm Diameter tube

D5                     8.277           1.301            12mm Diameter tube

D6                     10.555         1.2845          12mm Diameter tube

D7                     13.095         1.2605          12mm Diameter tube

D8                     15.161         1.2745          12mm Diameter tube

Fantastic Azimuth plot of this 10el 50MHz OWL Yagi

The Elevation plot is really clean too. A quiet antenna compared with most!


This SWR plot is taken with the Coaxial stub embedded within the EZNEC model Ever seen a 12.5 Ohm antenna like this one before? Watch how many now appear on the Internet but remember where you saw them first.


The G0KSC OWL element layout. Note the close spacing of the first 3 elements which give the OWL its extra gain and wide bandwidth.


As always, or if you have difficulty tuning, please Email me!


Justin G0KSC