Wireless Linear Network

A Linear Network topology is ideal for providing communications in systems that naturally require stations deployed along a line. Some of the applications are:
Railway wayside communications
Pipeline communications
Highway roadside communications
Long links that requires multiple repeaters between the end pointsThe figure shows the general topology of a Wireless Linear Network. Each node in the network has at most two neighbors with which it can communicate directly. Each station in the network uses a single radio, the PulsAR-24027 Wireless Ethernet Bridge , which comes equiped with a two antenna ports.
The following are some characteristics of the AFAR wireless linear network:
Each node consists of a single radio with two RF ports. Typically a node is deployed with two directional antennas pointing at each of the node's neighbors.
Each node has an Ethernet port for connection to a LAN or directly to the user equipment.
A packet can enter the linear network at any node, through the Ethernet port. If the packet is addressed to a station at a remote LAN, the radio transmits the packet to its right or left neighbor as necessary. The packet may then go through multiple hops in one direction until it exits the linear network at its destination.
When a packet goes through multiple hops, the packet does not show up at the local LANs of the intermediate nodes.
The network supports broadcast packets, which are transmitted, left and right, until they show up at every local LAN.
The behavior described in the above paragraphs is self-learned. No user configuration is required.
All radios are peers, there is no master radio providing synchronization, therefore no single point failure.
If a node fails, the two segments of the original linear network continue to operate as two separate linear networks. Once the failed node is reactivated, the two networks automatically merge into one.
The Linear Network topology is designed to be an integral part of the Afar SPAN Network which can synchronize the transmissions of co-located radios . Therefore the nodes can be co-located with AFAR radios running in Point-to-Multipoint and Point-to-Point without generating self-interference.

Ham Radio Activities

Although a ham radio does broadcast in all directions, hams generally do not use their radios in a broadcast kind of way as a disk jockey would at a radio station. In normal AM or FM radio, one disk jockey transmits and thousands of people listen. Hams, on the other hand, conduct two-way conversations, often with another ham or with a group of hams in an informal roundtable. The roundtable of hams may be in the same town, county, state, country or continent or may consist of a mix of countries, depending on the frequency and the time of the day. Hams also participate in networks, often called nets, at predetermined times and frequencies to exchange third-party messages. In the case of disasters, hams exchange health and welfare information with other hams. Some hams use radioteletype, (RTTY) with computer screens replacing the noisy teletype machines of the past.
Photo courtesy -->Computer-assisted radioteletype
Many hams get their start on VHF FM, using battery-operated hand-held transceivers set to transmit on one frequency and receive on another frequency. They use FM repeaters, set up and supported by local radio clubs. These repeaters borrow antenna space from TV-station-tower owners on top of mountains and high buildings to receive and re-broadcast signals to extend the range.
Photo courtesy -->

Kenangan di Cameron Highland

BERSAMA 9W2BCH & 9W2OCS SERTA KELUARGA