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6el 12.5Ohm 6m

A 6el 12.5 Ohm 50MHz Optimised Wideband Low impedance (OWL) Yagi

Revised 3rd February 2010

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 here

Visit HERE to learn how to make the OWL Match/Balun

Do not look at the gain figure of this antenna and compare with other 6 element 50MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With 11.85dBi and a boom less than 6M long, this antenna will be a winner for field days and the rural Ham radio operator.

PLEASE NOTE:
  • 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 results, Email me for details

 

Performance UK/USA Version

Forward Gain:                           11.85dBi at 50.250MHz

Front to Back Ratio:              19.23dBi at 50.250MHz

Peak Gain:                                 11.86dBi

Peak F/B:                                20.08dB

Bandwidth:                               500KHZ below 1.2:1

 

Build Dimensions for UK/USA Version

Element           Spacing in metres Half element Length in metres            Element Notes

Reflector               0                                   1.4985                                             12.7mm 1/2 inch Diameter tube

DE                       .280                              1.4475                                             12.7mm  1/2 inch Tube

D1                       .855                               1.4025                                            12.7mm 1/2 inch Diameter tube

D2                     2.280                               1.3575                                             12.7mm 1/2 inch Diameter tube

D3                     4.218                               1.3325                                             12.7mm 1/2 inch Diameter tube

D4                     5.975                               1.3235                                            12.7mm 1/2 inch Diameter tube

 

 

 

Build Dimensions for European Version 12mm tube

Element           Spacing in metres Half element Length in metres            Element Notes

Reflector               0                                   1.498                                             12mm Diameter tube

DE                       .298                               1.4475                                           12mm Diameter tube

D1                       .859                               1.4025                                           12mm Diameter tube

D2                     2.280                               1.359                                             12mm Diameter tube

D3                     4.218                               1.3335                                           12mm Diameter tube

D4                     5.975                               1.322                                             12mm Diameter tube

 

Build Dimensions for European Version 10mm tube

Element           Spacing in metres Half element Length in metres            Element Notes

Reflector               0                                   1.4995                                            10mm Diameter tube

DE                       .260                               1.449                                             10mm Diameter tube

D1                       .851                               1.4035                                           10mm Diameter tube

D2                     2.265                               1.3625                                           10mm Diameter tube

D3                     4.214                               1.338                                             10mm Diameter tube

D4                     5.975                               1.3235                                           10mm Diameter tube

 

 

Fantastic Azimuth plot of this 6el 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

 
 
 
 

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