Vine Antennas AS-OCF-404-HP | High Power Antenna
Bands: 40M, 20M, 15M, 10, 6M, 4M (17M, 12M With External ATU)
Power: 1Kw pep Max
Overall Length: 69 Feet (21.03 Meters)
An Off-Centre Fed Dipole for
40M, 20M, 15M, 10M, 6M & 4M
30M, 17M (with ATU)
What’s an Off-Centre Fed Dipole?
A traditional Dipole is a half-wavelength radiator, fed in the Centre with two equal length legs, the Off-Centre-Fed Dipole is a Dipole whose feedpoint is at a point removed from the centre of the antenna.
A traditional dipole is fed in the centre with 50-ohm coax, or more correctly through a 1:1 balun, whereas the off-centre fed dipole is fed through a 4:1 balun.
Your AS-OCF-404 has a specially designed balun which offers both a 75-ohm and 200-ohm output allowing two pairs of elements to be connected. One set of elements is a traditional dipole for 4M (70MHz) and the other an OCF Dipole for HF & 6M.
Why Off-Centre Feed a Dipole?
By moving the feedpoint of the dipole from the centre to off-centre, we create a multi-band antenna with multiple resonant points. We also change the feedpoint impedance and therefore need a carefully designed balun to provide a match to 50 ohms.
A centre fed dipole is only resonant at one single frequency, the off-centre fed dipole is resonant on multiple frequencies.
Your AS-HF-OCF-404 has been tested for resonance and is resonant on the 40M, 20M, 15M, 10M, 6M & 4M amateur bands and needs no external ATU.
The antenna also offers a reasonable match on the 12M, 17M and 30M amateur bands but must be used with an ATU
Where is it Resonant?
By careful design of the balun and feedpoint of the antenna, your AS-HF-OCF-404 has the following resonant points from 0 – 100MHz:
Roll out the elements and hang the shorter bare copper elements for 4M below the HF elements using the spacers provided.
Figure 1 – Antenna Wire Spacer Front
Figure 2 – Antenna Wire Spacer Above
Bands:40M, 20M, 15M, 10M, 6M, 4M
plus 30M, 17M, 12M (with ATU)
Power:1Kw pep Max
Overall Length:69 feet (21.03 meters)