Patterns in propagation

Easy access to computers, and the need to justify time spent on them, has encouraged research workers studying radio wave propagation to concentrate on those tasks which would be too complex or too time-consuming to undertake by hand. This paper attempts to show that there is still a place for the simpler approach. None of the studies mentioned in it has made use of anything more complicated than a programmable pocket calculator, yet, in some cases, the results have succeeded in challenging conventional theory. Patterns compress a great deal of information into visual images wherein absolute values are often irrelevant. The paper provides a selection of examples dealing with both isonospheric and tropospheric propagation.