A brief note on a small lightweight beam for 6 m.
Based on the 2 m design. It gives about 4.5 dBd gain, FB is not too good but still usable.
Computed polar plot for 2-element 6m Yagi
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ANALYSIS of 2ele50.ANT on 04-03-00 at 21:09 |
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| 2-ele beam for 6 metre Free space symmetric 50.150 MHz 2 6061-T6 wires, metres |
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| de = driven element Diam. 13 mm |
2.73 |
| sp1 = spacing between elements |
1.17 |
| re = reflector Diam. 13 mm |
2.92 |
| Impedance |
50.3 + j 4.1 Ohm |
| SWR |
1.09:1 |
| Efficiency |
99.7% |
| Forward Gain |
4.31 dBd |
| F/B |
8.62 dB |
| Azimuth Beamwidth |
69° |
| Elevation Beamwidth |
131° |
The constructed using 1 inch (2.54 cm) square section aluminium boom 48 inches (121.9 cm) long.
Elements 1/2 inch (1.3 cm) diameter aluminium tube.
Plastic dipole centre as in the 2 m design. The dipole elements are cut to 136.5 cm, which attach either side of the plastic dipole centre. So the over all element is longer than shown on the diagram by about 3-4 cm as the elements are spaced either side of the 1 inch boom and about 1-2 mm space between the ends of the elements and the boom.
I feed directly with 50 ohm coax with a choke balun made by just making a 4 inch diameter 3 turn coil in the coax cable at the antenna feed point. I use some RG58 coax to make the balun which seems OK with 100 Watts transmit power. SWR about 1.15: 1 in the SSB portion of the band.
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