Dual Band Quads

21Mhz OWA Yagi Antennas

A 7el 12.5 Ohm 144MHz Optimised Wideband Low impedance (OWL) 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 7 element 144MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With 12.73dBi and a boom of 3M long and a single antenna sky temperature of 252.9 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 1.4MHz 1.1:1 bandwidth too!

 

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 Low Temperature antenna, ideal for EME work

The lower antenna is a 7el OWL by G0KSC at YU2MMA

 

Performance UK/USA Version

Forward Gain:                           12.73dBi at 144.300MHz

Front to Back Ratio:                 28.24dBi at 144.300MHz

Peak Gain:                               12.76dBi

Peak F/B:                                28.41dB

Bandwidth:                              1.4MHz below 1.1:1

Sky Temp. TA:                        252.9 Kelvin

G/T:                                        -11.32dB

 

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

Sky Temp. TA:                         244.3 Kelvin

G/T:                                        -5.21dB

Gain:     18.67dBi

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                                   .5145                                           3/8 inch tube

DE                       .127                               .4925                                           1/2 inch tube

D1                       .359                               .4795                                           3/8 inch tube

D2                       .830                               .463                                             3/8 inch tube

D3                     1.496                               .4505                                           3/8 inch tube

D4                     2.256                               .438                                             3/8 inch tube

D5                     3.001                               .4245                                           3/8 inch tube

 

Build Dimensions for European Version

Element           Spacing in metres Half element Length in metres            Element Notes

 

Reflector               0                                   .514                                            10mm tube

DE                       .127                               .4935                                          12mm tube

D1                       .359                               .479                                            10mm tube

D2                       .830                               .4625                                          10mm tube

D3                     1.496                               .450                                            10mm tube

D4                     2.256                               .4375                                          10mm tube

D5                     3.001                               .424                                            10mm tube

 

Antenna Plots

Fantastic Azimuth plot of this low temperature 7el 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