Abstract: Ultra low frequency transmissions can be used to penetrate obstructions to areas where other operation of other communication devices may be limited, such as in a mine, tunnel, or other underground location. A portable device that includes a supercapacitor, a transmitter, and an antenna can be used to communicate using ultra low frequency transmissions. In one aspect, a communication device comprises a supercapacitor; a transmitter powered by the supercapacitor; and an antenna connected to the transmitter for sending messages. In another aspect, a method for communicating comprises the steps of receiving a message to be transmitted, powering a transmitter from a charged supercapacitor, and transmitting the message via an antenna.

Abstract: An ultra low frequency transmission system can provide communications, for example, messages, to an individual or a group in areas of a building where conventional transmission reception is limited. A communication system for a structure includes a transmitter and an antenna network extending substantially throughout the structure. The antenna network includes a first portion and a second portion. At least one location in the structure can receive a transmission from the first portion and the second portion of the antenna network. The antenna network is configured to receive the transmission from the transmitter and to communicate the transmission throughout the antenna network to at least one receiver configured to receive the transmission from the transmitter via the antenna network. The antenna network transmits the transmission using an ultra low frequency to the at least one receiver.

Abstract: A method and apparatus for producing an elongated beam from compressible material. A mixture of filling material and plastic material is delivered to a first space and there compressed. The compressed material is pressed through a nozzle into a second space defined by a matrix of wall parts, where the material is made more rigid. The wall parts of the matrix can be moved backwards and forwards in a particular sequence to enable beam parts to be fed continuously through the matrix.