Figure 8: Cluster Tree Network Topology; Figure 9: Working Around Obstructions - Geokon GeoNet 8800 Series Instruction Manual

If direct communication is not possible for some nodes, then other nodes will
automatically relay their data to the supervisor. This effectively creates a cluster
tree topology. The figure below illustrates this concept.
Cell
Ethernet
USB/RS-232

FIGURE 8: Cluster Tree Network Topology

Each transmission from node to supervisor or node to node is considered one
"hop". Examples of hops are shown in figures above and below. Up to four hops
can be made between a node and the supervisor. With the ability to hop comes
the ability for the supervisor to communicate with nodes that have not
established direct radio communication. The figure below shows how GeoNet
devices can operate around buildings or other barriers using hops.
1 Hop

FIGURE 9: Working Around Obstructions

When using GeoNet, it is important to understand the effect that obstructions
have on radio signals. Obstructions between two antennas can cause reflections
of the transmitted signal. When these reflections arrive at the receiving antenna,
they may be in or out of phase with the signal that took a straight-line path. This
MODEL 8800 SERIES GEONET WIRELESS DATA ACQUISITION NETWORK | INTRODUCTION | 7
1 Hop
S = Supervisor
N = Node (1, 4, 8, ADR)
= Data Path
1 Hop
1 Hop
8:
1 Hop
9:
Obstruction