Radio Broadcast (May-Oct 1922)

148 RADIO BROADCAST Screw Eye Insulator Support Screw Eye hPorcelain Tube Porcelain Knobs Board Projecting 4 to 5 ft Fig. 7. ANTENNA ERECTED ON APARTMENT In general the best form of an antenna for receiving from amateur and broadcasting stations is a single wire from 75 to 150 feet long and supported 25 to 50 feet high Figure 5 illustrates an ideal antenna for use on a private estate. The wire should be not smaller than No. 14 B. & S. Gauge Copper or its equivalent. Any joints either in the antenna wire proper or in the lead-in should be as shown in Figure 6 or should be soldered. Twisted joints unless soldered are very unreliable, as they corrode. In fact, poor joints in the antenna wire frequently cause a falling off in signal strength as time goes on due to the corroding action. If it is desired to install an antenna on the roof of an apartment house, the sketch shown in Figure 7 should be followed. The supporting posts should hold the antenna wire at least i 5 to 20 feet above the roof of the apartment and the lead-in wire should be run over the side of the apartment as shown. In no case should the lead-in be run down an elevator shaft or through metal conduit and it should be held from 2 to 5 feet away from the side of the apartment even if the wire be insulated. If the apartment is so built that an elevator shaft or some other part of the structure rises above the roof of* the house, the antenna ma>' be attached to it as shown in Figure 8. In all cases, however, where the end of the antenna wire is attached to a grounded structure, the tie wire on the ground side of the insulator should be at least 2 feet long. It frequently happens that it is impossible to install the lead-in wire so that it is sufficiently far from the side of the apartment house and all other grounded objects to give best results. This condition will be experienced if the owner of the set occupies a lower floor of a tall apartment that is located very closely to an adjacent building. In such cases, the owner of the set must realize that he will not obtain as good results as his neighbor on one of the top floors. The most ideal place for the receiving instruments located in a tall building is on the top floor. Good results can, however, be obtained on the lower floors if proper precautions are taken. At times, proprietors of hotels or of restaurants located on the ground floor of tall buildings install receiving sets with loud speaking devices and they are frequently disappointed in the results obtained. Unless properly informed, they have the radio receiver installed in the room where the music is to be heard and the lead-in will probably be led down near to the side of the building and in some cases will Tie Wire at least 2 Feet long Fig. 8. Antenna erected on apartment and supported from tower LEAD IN