| 摘要 |
PROBLEM TO BE SOLVED: To conveniently perform communication between an equipment in a hole and a ground equipment in a comparatively shallow boring hole without using a special signal cable. SOLUTION: A pseudo coaxial cable 28 is formed by inserting one lead wire 22 into an air tube 18 provided in the boring hole 16 and an electric signal is transmitted between the ground equipment and the equipment in the hole (a sensor circuit unit 14 in embodiment) by the coaxial cable 28. Transmission and reception of the signal is preferably performed by transmitting the encoded signal from one of the ground equipment and the equipment in the hole by using the coaxial cable and decoding the received encoded signal at the other side. In this case, a power is supplied from the ground to the equipment in the hole by using the lead wire 22 by using a metal rod 10 and a metal pipe inserted into the boring hole 16 as the electrical ground and the signal is also superimposed on power supply. |
