A 13el 28 Ohm 144MHz Optimised Wideband Low impedance (OWL) 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 13 element 144MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With 16.44dBi (10mm element version) and a boom less than 8.3M long, this antenna will be a winner for field days and the rural Ham radio operator. Class leading G/T figures 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
Performance UK/USA Version
Forward Gain: 16.43dBi at 144.300MHz
Front to Back Ratio: 26.61dBi at 144.300MHz
Peak Gain: 16.47dBi
Peak F/B: 26.81dB
Bandwidth: 1.9MHz below 1.1:1
Build Dimensions for UK/USA Version
Element Spacing in metres Half element Length in metres Element Notes
Reflector 0 .512 3/8 inch tube
DE .202 .4955 1/2 inch tube
D1 .383 .4775 3/8 inch tube
D2 .845 .465 3/8 inch tube
D3 1.484 .4555 3/8 inch tube
D4 2.236 .4475 3/8 inch tube
D5 3.045 .441 3/8 inch tube
D6 3.901 .4355 3/8 inch tube
D7 4.779 .430 3/8 inch tube
D8 5.672 .4255 3/8 inch tube
D9 6.583 .421 3/8 inch tube
D10 7.508 .4205 3/8 inch tube
D11 8.256 .433 3/8 inch tube
Build Dimensions for European Version
Element Spacing in metres Half element Length in metres Element Notes
Reflector 0 .5115 10mm tube
DE .202 .496 12mm tube
D1 .381 .477 10mm tube
D2 .845 .4645 10mm tube
D3 1.484 .455 10mm tube
D4 2.236 .447 10mm tube
D5 3.045 .4405 10mm tube
D6 3.901 .435 10mm tube
D7 4.779 .4295 10mm tube
D8 5.672 .425 10mm tube
D9 6.583 .4205 10mm tube
D10 7.508 .420 10mm tube
D11 8.256 .4325 10mm tube
Antenna Plots
Fantastic Azimuth plot of this 13el 144MHz 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 28 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 at all, please Email me!
Justin G0KSC