Ralph Holland: antenna simulation publications
Another hobby of mine (VK1BRH).
Most of the following simulations have been performed with computer simulation using EM tools such as NEC-2, which is available via anonymous ftp or at the NEC Unofficial home page. You can also obtain further information from the Applied Computational Electromagnetics Society (ACES). Tools such as MININEC, NEC, ELNEC etc are derived from common ancestors which use the Method of Moments as a basis. Other research continues[1].
- Short Vertical Antennas and Ground Systems - VK1BRH, Ralph Holland, Amateur Radio, Vol 63 No 10, October 1995, pp 9-13, WIA.
- This article describes how an effective ground system can be produced for a short vertical antenna. The article explores ground losses and elevated sradial systems. A case study is presented for a 3 radial elevated groundplane.
- Spiral Top-loading of a Short Vertical , Ralph Holland, Amateur Radio, Vol 63 No 10, October 1995, pp 16-18, WIA.
- This article explores how spiral top-loading can be employed to significantly reduce the height of a resonant radiator. Experimental results show howa 1.5m vertical can be resonated between 1.6 and 3.5 MHz! An attempt has been made to quantify the system losses. When the technique is applied to a 10 m vertical the losses can be reduced to about 3 dB at 3.5 MHz.
- Horizontal Antennas Above Real Ground, Ralph Holland, Amateur Radio, Vol64 No 10, Oct 1996, pp 22- 24, WIA.
- This article shows how the impedance of a horizontal dipole is affected by the ground parameters and mounting height. Various plots are provided to show the effect of frequency and ground parameters. Two tables are provided detailing the r.f. loss resistance in circular copper conductors.
- Horizontal Half-wave Dipole Above a Counterpoise, Ralph Holland, AmateurRadio, Vol 64 No 11, Nov 1996, pp 12-13, WIA.
- This article describes how the efficiency of a dipole can be improved byplacing it above a counterpoise. An optimimum height and separation is observed which can be used to obtain an improvement of approximately 40%in efficiency. The radiation pattern is also displayed.
- Hybrid Antennas, Amateur radio, Ralph Holland, Amateur Radio, Vol65 No 1, Jan 1997, pp 10-14, WIA.
- This article is a treatise on antennas that use a combination of vertical and horizontal polarisation. There is a comparison table where the pros and cons of a particular configuration can be weighed up against the constructionand location. Radiation patterns, complete with holes, are displayed in a three-dimensional plot and charts are provided showing the feedpoint impedance and total system efficiency for various soils.
Copyright (c), Ralph Holland - VK1BRH, 1997 - 2004