Fig. 78. "United" Wireless Anchor Gaps.
The construction and connection of a simple anchor gap are shown in Fig. 79. A ring 1 3/4 inches outside and 1 1/4 inches inside is cut out of 5/8-inch hard rubber or fiber and smoothed up. Three 1/8-inch holes are bored in the periphery of the ring at 120 degrees to each other. The holes are threaded with a 10-24 tap. Three small binding posts are each fitted with a 3/16-inch brass rod 7/8 inch long, having a 10-24 thread so that they may be screwed into the holes in the ring.
Fig. 79. Anchor Gap.
The gap between the ends of the two rods connected to the aerial and the receiving apparatus is adjusted until it is about 1/8 inch long. The third point is screwed in until it all but touches the other two.
CHAPTER XII. HOT WIRE AMMETER.
When a current passes through a conductor, it generates heat in proportion to the resistance offered and the amount of current flowing. Heat causes metals to expand sufficiently so that these two properties may be applied to the construction of a hot wire ammeter for the measurement of alternating currents of high frequency and potential.
The hot wire ammeter is placed in series with the aerial, so that by noting the deflection of the pointer, the inductance, capacity and spark gap may be adjusted until the meter gives a maximum reading.
