An 8el 12.5 Ohm 144MHz Optimised Wideband Low impedance (OWL) Very Low Temperature Yagi
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 in the CONSTRUCTION menu above.
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