SB4 is an ORBIT sandbox that is intended to support medium size experiments with up to 9 nodes with tightly controlled topologies. The single Atheros device in each node is connected to the 9 inputs of(JWF) 50PMA-012 RF matrix switch. This switch, with its programmable attenuators, enables creation of 36 possible RF paths between the nodes and thus facilitates creation of large number of topologies in which nodes can be organized. Each of the 36 attenuators can be set to a maximum of 63 dB of attenuation. In order to achieve good isolation between the RF devices in the nodes as well as given the physical proximity to the main grid which would result in interference, each of the SB4 nodes is stored in Ramsey Electronics STE2300 shielded enclosure which provide up to 80 dB of isolation.