Page:United States patent 1530129.pdf/3
| Patented Mar. 17, 1925. | No. 1,530,129. | |
United States Patent Office. Edward H. Loftin of Washington, District of Columbia and Henry Lyon of Hyattsville, Maryland. Radio Signaling System. Application filed April 5, 1920. Serial No. 371,587 | ||
To all whom it may concern:
Be it known that we, Edward H. Loftin and Henry H. Lyon, citizens of the United States, and residents, respectively, of the 5city of Washington, in the District of Columbia, and Hyattsville, in the county of Prince Georges and State of Maryland, have invented an Improvement in Radio Signaling Systems, of which the following is a 10specification.
Our invention relates to antennæ for radio signaling and has for its object improved operation in types of antennæ known as “low horizontal”, such as were disclosed in 15U. S. Letters Patent 760,463 of May 24, 1904 to Marconi; 771,819 of October 11, 1904, to De Forest; 795,762 of July 25, 1905 to Garcia; 1,101,533 of June 30, 1914, to De Forest; 1,220,005 of March 20, 1917, to Rogers and Lyon; 1,303,730 of May 13, 1919, 20to Rogers; 1,322,622 of November 25, 1919, to Rogers and Lyon and in an article by F. Kiebitz in The Electrician of March 8, 1912.
25For the purpose of describing our invention we have diagrammatically illustrated in the accompanying drawings some of the antennæ disclosed in the above references as follows:
30Figure 1 shows an antenna abcd somewhat elevated above the surface of the earth by the insulated supports 2, y representing insulators, and associated near its middle point with proper signaling instruments s. 35Figure 2 shows an antenna abcd buried somewhat under the surface of the earth and associated near its middle point with proper signaling instruments s. Figure 3 shows an antenna abc buried somewhat under the 40surface of the earth and insulated therefrom by the conduit or other form of insulator g, associated with proper signaling instruments s near one end, and grounded at c. Figure 4 shows an antenna abc 45somewhat elevated above the surface of the earth by the insulating support 2, y representing insulators, associated near one end with proper signaling instruments s, and grounded at c. Figure 5 shows an antenna 50abc trailed astern of a vessel, associated within the vessel with proper signaling instruments s, and grounded within the vessel at c.
It is now well known that these types of antennæ may be operated either bare or55 insulated, either in dry or we soil, and either in fresh or salt water, and this need not be discussed here.
While the diagrammatic figures show but single wires, multiple wires bonded together60 at various points, or separated and connected near the signaling instruments, may be employed if desired.
It will be noted that the antennæ illustrated all have a vertical component small65 or practically nil compared to the horizontal component, and in operating with these antennæ we have found that, unlike elevated antennæ they are practically untunable by using a concentrated variable70 inductances or capacities, but that a decided condition of tune or best signal can be obtained by making the horizontal component a certain physical length for a given wave length; that is, seeking the optimum 75horizontal length of antenna for a given wave length. For instance, in a buried wire installation having an antenna of total length of 300 feet we found that we could not hear a certain station on its usual 80operating wave length of 600 meters, but when we caused this station to send signals on various wave lengths we found that on 950 meters very strong signals were obtained, while at 150 meters each side of this 85point the signals became almost inaudible. We have also found that this optimum length of the horizontal component does not bear a definite relation to the wave length for different conditions, but may vary through90 very wide limits depending upon many considerations such as: character of surface of the earth, size of wire, height above the surface of the earth if elevated, and characteristics of insulation if under the surface95 of the earth and insulated, and the proper length of antenna can only be found by trial and error. We have found, however, in our investigations, that the required length is considerable less than a half wave100 length.
This necessity for tuning or obtaining maximum signal effect by choosing the proper length of horizontal component rather than using concentrated variable 105inductances or capacities becomes more pronounced as the ratio of horizontal component to the vertical component increases, the