US1530129A - Radio signaling system - Google Patents

Description

March 17,1925. 1,530,129

E. H. LOFTIN ET AL RADIO SIGNALING SYSTEM Filed April 5, 1920 2 Sheets-Sheet 1 March 17, 1925. 1,530,129

E. H. LOFTIN ET AL RADIO SIGNALING SYSTEM Filed Ap l 5, 1920 2 ShGGtS-ShGGt 2 A A Y a a b a 2 z 2 a linl Patented Mar. 17, 1925.

EDWARD H. LOFTIN, or WASHINGTON, DISTRICT or ooLuMBIA, AND HENRY H. LYON, or HYATTSVILLE, MARYLAND.

RADIO SIGNALING SYSTEM.

Application filed April 5, 1920. Serial No. 371,557.

- signaling and has for its object improved operation in types of antennae known as low horizontal, such as were disclosed in U. 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, to 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,

For the purpose of describing our invention we have diagrammatically illustrated in the accompanying drawings some of the antennae disclosed in the above references as follows Figure 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 .9. F ig ure 2 shows an antenna abcd buried somewhat under the surface of the earth and associated near its middle pointwith proper signaling instruments 8. Figure -3 shows an antenna abs buried somewhat under the surface of the earth and insulated therefrom by the conduit or other form of ins'ulator 9, associated with proper signaling antennae may be operated either bare or insulated, either in dry or wet 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 together at various points, or separated and connected near the signaling instruments, may be employed if desired.

It will be, noted that the antennae illustrated all have a vertical component small -or practically nil compared to the horizontal component, and in operating with these antennae we have found that, unlike elevated antennae they are ractically untunable by using concentrated variable induetances or capacities, but that a, decided condition of tune or best signal can be obtained by making thehorizontal component a certain physical .length for a given wave length; that is, seeking the optimum horizontal 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 operating wave length of 600 meters, but when we caused this station to send signals on various wave lengths we found that on 950meters very strong signals were obtained, while at 150 meters each side of this point the signals became almost inaudible. lVc have also found that this optimum length of the horizontal component does not bear a definite relationto the wave length for diiferent conditions, but may vary through 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 surface 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 considerably less than a half wave length.

This necessity for tuning or obtaining maximum signal effect by choosing the proper length of horizontal component rather than using concentrated variable inductances or capacities becomes more pronounced as the ratio of horizontal component to vertical component increases, the

5 nance extreme conditions being that of an antenna laid under the surface of the earth.

Having described our invention We claini:

1. In a system of radio signaling an antenna whose vertical component'with respect to earth throughout its, entire length is practically nil compared to'fsaid length, said length being of the order of one tenth of the wave length of an operating radio signal, said antenna being adjusted in resowith said signaling wave substantially entirely through adjustment of said length.

'2. In a system of radio signaling an antenn'a substantially parallel to and under the surface of the earth having a length of the order of one tenth'tlie Wave length of an operating signal, and adjusted in resonance with said signaling wave substantially entirely through adjustment of said length.

EDWARD H. LOFTIN. I

HENRY H. LYON.

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