Dual Band Quads

21Mhz OWA Yagi Antennas

An 8el 12.5 Ohm 144MHz Optimised Wideband Low impedance (OWL) Very Low Temperature Yagi

Revised  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 8 element 144MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With 13.71dBi and a boom less than 3.88M long and a single antenna sky temperature of 242.0 Kelvin, this antenna will be a winner for all those seeking the most quiet antenna of this size for 2M. Class leading G/T figures too! This antenna also has an incredible 900KHz 1.12:1 bandwidth too!

2 x 8el 12.5Ohm OWLs at CT1FFU/P. Tony reports the performance as 'excellent' with his station having very good 'ears'

 

M0WBM built this version and added the G0KSC fully adjustable folded dipole which gives a direct 50 Ohm feed point. Email me for info on adding this to any 12.5 Ohm OWL

 

The 8el OWL fitted with a fully adjustable folded dipole (50 Ohm) by G8FJG

 

 

G0KSC built this first Folded dipole version of the OWL. Thru-boom insulated elements have been used and just a choke balun at the feed point.

 

The Analyser shows a perfect 50Ohm match from use of the folded dipole.

 

PLEASE NOTE:

  • 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 insulators similar to G0KSC. If through boom/insulator/element bolts are used, add 3mm
  • This is a Very Low Temperature antenna, ideal for EME work

 

Performance UK/USA Version

Forward Gain:                           13.71dBi at 144.300MHz

Front to Back Ratio:                 28.38dBi at 144.300MHz

Peak Gain:                               15.31dBi

Peak F/B:                                27.31dB

Bandwidth:                              1.3MHz below 1.1:1

Sky Temp. TA:                        242.1 Kelvin

G/T:                                        -10.15dB

 

Four bay array (in metres) - 2.7V x 2.9H

Sky Temp. TA:                         233.3 Kelvin

G/T:                                        -4.19dB

Gain:     19.49dBi

Note: G/T and Sky temp figures always at 144.100MHz

Build Dimensions for UK/USA Version

Element           Spacing in metres Half element Length in metres            Element Notes

Reflector               0                                   .5165                                           3/8 inch tube

DE                       .124                               .4935                                           1/2 inch tube

D1                       .367                               .478                                             3/8 inch tube

D2                       .880                               .462                                             3/8 inch tube

D3                     1.553                               .4525                                           3/8 inch tube

D4                     2.305                               .442                                             3/8 inch tube

D5                     3.154                               .4335                                           3/8 inch tube

D6                     3.880                               .4275                                           3/8 inch tube

 

Build Dimensions for European Version

Element           Spacing in metres Half element Length in metres            Element Notes

 

Reflector               0                                   .516                                            10mm tube

DE                       .124                               .494                                            12mm tube

D1                       .367                               .4775                                          10mm tube

D2                       .880                               .4615                                          10mm tube

D3                     1.553                               .452                                            10mm tube

D4                     2.305                               .4415                                          10mm tube

D5                     3.154                               .433                                            10mm tube

D6                     3.880                               .427                                            10mm tube

 

Antenna Plots

 

Fantastic Azimuth plot of this low temperature 8el 144MHz 12.5Ohm OWL Yagi

 

 

The Elevation plot is really clean too. A super quiet antenna, find one the same size that is more quiet!

 

 

A Super quiet antenna that is wideband? Another first from G0KSC. 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 three elements. My 'secret' to wide band low impedance antennas I now release for all to use.

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

 

Justin G0KSC