RACOM RipEX 1.12.2, User Manual, Page: 35 / 189

lematic site seems to be usable after all (e.g. it can pass commissioning tests), it will keep generating
problems for ever, hence it is very prudent to do something about it as early as possible.
Note
Never design hops where a directional antenna is used for a direction outside its main lobe.
However economical and straightforward it may seem, it is a dangerous trap. Enigmatic
cases of drop-outs lasting couple of minutes every other day, over a clear LOS hops were
created exactly like that. They look like interference which is very difficult to identify and ,
alas, they are caused by pure multipath propagation, a self-made one. So always use a
combiner and another directional antenna if such arrangement is needed. Always.
combiner
correctly
incorrectly
Fig. 3.5: Main lobe
3.5. Network layout
In general a radio network layout is mostly (sometimes completely) defined by the application. When
the terrain allows for direct radio communication from all sites in the network, the designer can not do
too much wrong. Unfortunately for RF network designers, the real world is seldom that simple.
The conditions desireable for every single radio hop were discussed in previous paragraphs. If we are
lucky, assuming different layouts meeting those conditions are possible, we should exploit those layouts
35 © RACOM s.r.o. – RipEX Radio modem & Router
Network planning