An 11el 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 11 element 144MHz Yagis. Compare the gain, F/B and bandwidth together against other antennas of a similar boom length. With 15.28dBi and a boom less than 6.3M long and a single antenna sky temperature of 225.1 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!
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
The 11el 12.5Ohm OWL at G0KSC
Screen shot of the first EME QSO on this single 11el Yagi with no elevation and only 100 watts
Performance UK/USA Version
Forward Gain: 15.28dBi at 144.300MHz
Front to Back Ratio: 27.26dBi at 144.300MHz
Peak Gain: 15.31dBi
Peak F/B: 27.31dB
Bandwidth: 900KHz below 1.12:1
Sky Temp. TA: 225.1 Kelvin
G/T: -8.24dB
Four bay array (in metres) - 3.3V x 3.5H
Sky Temp. TA: 219.9 Kelvin
G/T: -2.33dB
Gain: 21.09dBi
Note: all G/T and sky temperature figures at 144.100MHz
Build Dimensions for UK/USA Version
Element Spacing (m) - Half element Length (m) - Element Notes
Reflector 0 .5155 3/8 inch tube
DE .111 .496 1/2 inch tube
D1 .293 .483 3/8 inch tube
D2 .718 .4685 3/8 inch tube
D3 1.328 .457 3/8 inch tube
D4 2.081 .4465 3/8 inch tube
D5 2.895 .440 3/8 inch tube
D6 3.739 .4335 3/8 inch tube
D7 4.619 .425 3/8 inch tube
D8 5.516 .418 3/8 inch tube
D9 6.297 .4245 3/8 inch tube
Build Dimensions for European Version
Element Spacing (m) - Half element Length (m) - Element Notes
Reflector 0 .515 10mm tube
DE .111 .4965 12mm tube
D1 .293 .4825 10mm tube
D2 .718 .468 10mm tube
D3 1.328 .4565 10mm tube
D4 2.081 .446 10mm tube
D5 2.895 .4395 10mm tube
D6 3.739 .433 10mm tube
D7 4.619 .4245 10mm tube
D8 5.516 .4175 10mm tube
D9 6.297 .424 10mm tube
Antenna Plots
Fantastic Azimuth plot of this low temperature 11el 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