G3SYC began designing and using a LPY on 6 metres in 1991. Since then he has refined the design and has worked some superb dx from his qth in IO93. The design featured here evolved in 1996, and is the mk2 version.
This yagi antenna has a very clean polar pattern and a good front to back ratio.
Here below you can find spacing and element lenght that you will find usefull in case you want to homebrew your own log periodic beam.
| SPACING | Inches | ELEMENT | LENGTH (Inches) |
|---|---|---|---|
| Radiator 1 | 114.6 | ||
| Rad.1 – Rad. 2 | 13.6 | Radiator 2 | 111.2 |
| Rad 2 – Rad 3 | 13.2 | Radiator 3 | 108.0 |
| Rad 3 – Rad 4 | 12.8 | Radiator 4 | 104.0 |
| Rad 4 – Dir 1 | 35.5 | Director 1 | 107.0 |
| Dir 1 – Dir 3 | 50.0 | Director 2 | 104.0 |
| Boom Length | 121.1 |
Some notes and assembling instructions
- The elements are made from 0.5 inch (13mm) aluminum tubing
- The boom is 1 inch (25mm) square section aluminum tube
- Attach the feeder to radiator 4
- All of the elements are mounted on plastic dipole insulators commonly found at radio rallies
- A shorting strip is connected across the terminals in the dipole insulator on D1 & D2
- The phasing strips are made from 1/8 inch (3mm) x 1/2 inch (13mm) aluminum strip
- All element lengths given are tip to tip
- The phasing strips are attached with the dipole insulator element securing bolts