|The question of Rifle Ranges having been of late so prominently brought before the public, and being of special interest to
Volunteer Corps and Rifle Clubs, we have considered it desirable to bring before those interested our system of Telephones for
allowing conversation to take place between the firing points and the target. In this connection we are enabled, by the courtesy
of the National Rifle Association, to offer the identical system which has for some time been in use at the Bisley Ranges.
This system provides at the firing pints a patented form of flush box which to outward appearance does not differ materially from the junction boxes used by telephone and electric light companies. This particular type of box, however. is specially fitted inside with a collapsible table and connecting terminals. The arrangement can be better understood by reference to the diagrams z, a, and 3. In these diagrams Figure r represents a sectional view of the flush box when not in use; Figure 2 represents the collapsible table extended and the K 570 Bisley Telephone attached; whilst Figure 3 represents the method of connecting the tine wires to the terminals. At Figures z and a it will be observed that the flush box has two tubular projections, a and B, cast on the inside, forming inlets to the box from the under side. The larger of these tubes, a, is to accommodate a telescopic tube, which is an arrangement consisting of an outer tube c, and an inner tube d. The collar a is screwed to and the shoulder f on the end of the inner tube prevents it. being pulled right out. A hole is provided in d, so that when the top is extended, a pin thrust through this bole keeps the tube up.
The lines for a Rifle Range Telephone should, if possible, be run underground, and at each firing point they should be cut, and the ends led into the box by tube PS. as shown at Figure 3. There are two methods of wiring possible, the first, and most preferable. consisting of two lines for the whole length of the range; and the second, consisting of a single line, using earth for the return. This latter method is satisfactory, provided a good earth connection is made. If the first plan is used, the wires should be cut at the firing point, and the ends taken into the box by tube PS. They should be connected to the terminal plates. The line wire L should be taken to connecting screw 4 on one terminal, and a connection taken from screw i down a tube PS. The wire L should be taken to connecting screw 4 of the remaining terminal, and a connection from i down the tube 6; thus it will be seen that the lines arc simply looped into the box, and a terminal connected in circuit with each. If a connection is now taken from the screws j and i, they will form a sap with the two lines at whichever point is necessary. If a single line is used with an earth return, the terminals j and ; would be provided with a connecting bridge k, as in Figure 6. The single wire L comes up tube 6, and is connected to screw 4; the continuation is taken from screw i, so that the wires L L, with the terminals and link 4, form a continuous conductor through the inside of the box. The earth connection should be made at each end of the range, or, where an armoured cable is used, the armouring itself can be utilised as earth. In this case it will be necessary to see that at each point the armour of the in going cable is connected across to the armour of the outgoing cable. To connect the telephone it is necessary to first remove the link k, and then connect on to the screws j and i, If the telephone is moved to another point the link k must be replaced. or no Communication can be obtained.
It might be thought that a simpler method would be to use one terminal only at the box, and connect the in going and outgoing wires so that the telephone would be tapped on to the line, but this would necessitate making an earth connection at every point, it is therefore necessary, in order to terminate the lines at the targets, that a simple teak strip is required with two terminals for fixing the ends of the wires to, so as to afford a convenient means for connecting the target instrument.
If a cheaper arrangement is preferred, a modified system can be adopted by using K 620 flush Box for fixing in the ground or K 640 for fixing to posts. In this case the Portable Sets K 550 or K 560 should be used. and connection established with the lines through a Plug and Flexible Cord K 630. The terminal instrument can be of the K 68 type.
Still another method of making Connection is that of using K 600 Spring Jack, which can be let into wood posts, and a connection with the portable set established by using Plug and Cord K 610.
Last revised: November 06, 2022