Optimal stacking distances are dependent on carefully chosen dimensions. DL6WU's formula is a good starting point but may not always deliver optimum results. When using a box configuration of four yagis see table below for recommended distances that will deliver the best outcome for these G4CQM's Antennas yagi designs...
|Design||Horizontal (mm)||Vertical (mm)|
DL6WU based stacking calculator, simply enter the -3dB Beam Width (Degrees)...
|Conventional yagi four stack||Diamond configuration|
|Conventional Total Field||Diamond Total Field|
|Conventional in AGTC LITE||Diamond in AGTC LITE|
Terrestrial DXers working Tropo etc should carefully consider using Diamond configuration. Although spacing distances required are greater than Conventional, a tighter and more directional pattern could be very useful! Diamond configuration creates an apparent large forward lobe, secondary sides and rear dramatically reduced. However, when considering EME, use of Conventional offers lower temperatures up to and including 30° elevation. From then on up Diamond truly has the advantage!
Diamond configuration also reduces mutual coupling problems, yagi to yagi, because stacking distances are greater!
Symbolic Dimensions makes easy work of experimenting with stacking distances, see .nec files below...