8 Band Log Periodic Dipole Array (10, 11, 12, 15, 17, 20, 30, 40m)
Log Periodic Dipole Array (LPDA) antennas have very broadband characteristics and are suitable for HF multi-band operation. LPDA is a directional antenna with good forward gain and acceptable front-to back (F/B) ratio. The only down-side of the LPDA is its big size. Being a virtual environment, size is of no consequence on HS4. We can afford to deploy and use large antennas on the system. A typical Log Periodic antenna can easily cover almost the entire HF spectrum while maintaining excellent SWR and feed-point impedance characteristics. LPDA allows a very simple interface to the transmission line. Complex impedance matching arrangement is not required to drive the LPDA. A 50 ohm co-ax cable with a 1:1 Balun is all that is needed to achieve excellent performance across all bands.
We have specially crafted this LPDA antenna for HamSphere 4.0. It has been tailored to provide optimal performance and good value for money. This antenna covers 8 bands from 40m to 10m (40-30-20-17-15-12-11-10m). It has a boom length of 29m and a span of 24m. This LPDA has 16 log periodic elements plus 2 additional parasitic directors to further enhance performance. The average gain across bands is a little over 12 dBi thus ensuring excellent long range capabilities. The antenna is hoisted and mounted on a tower at the height of 30m (100 ft) above ground to ensure good low angle radiation pattern. This LPDA antenna is the first in the series of Log periodic Dipole Array antennas being deployed on HamSphere 4.0