US2295302A - Antenna - Google Patents

Description

Patented Sept. 8, 1942 ANTENNA Walter 0. Spoon, Goldendale, Wash., assignor of one-half to George S. Klein, Goldendale, Wash.

Application February 8, 1941, Serial No. 378,050

3 Claims.

This invention relates generally to radio receivers and particularly to an antenna.

The main object of thi invention i to construct a loop antenna of the nonresonant, low impedance type.

The second object is to construct an antenna of the type mentioned which would be extremely rugged and easy to construct and having a total absence of body capacity effect, as well as having a reduced antenna effect or vertical effect, which makes for sharper tuning, thus making it an ideal loop for marine use as a radio compass.

The third object is to construct an antenna of the class described which is equally adaptable for use on the lower frequencies as well as the higher frequencies, thereby-eliminating the necessity of separate loops for each wave band.

The fourth object is to construct an antenna which is especially adaptable as a direction finder for aircraft work, since it ope-rates at ground potential and so needs no shielding, thereby reducing rain static to a minimum and also reducing losses due to high impedance conductors running through shielding.

The fifth object is to construct an antenna of the class described which is especially useful in connection with the receivers in geophysical prospecting equipment of the radio balance type, due to the entire absence of body capacity effect. When so used, the wabble so common'in the high impedance loops when carrying the receiver over rough ground, is eliminated. It also reduces the capacity effect of vegetation.

The sixth object is to construct a loop of the class described which is adapted for use on under-water equipment such as submarines because it is always at ground potential and at low impedance, capacity due to water has little or no efiect on its operation.

The seventh object is to construct an antenna of the class described which is easily adaptable for automotive mounting as the metallic car body produces little capacity effect.

The eighth object is to produce an antenna of the class described having a precision adjustment for the balancing of the loop.

These and other objects are accomplished in the manner set forth in the following specification as illustrated in the accompanying drawing, in which:

Fig. 1 is a front elevation of the antenna showing a matching circuit to a conventional radio receiver.

Fig. 2 is a plan of Fig. 1.

Fig. 3 is a horizontal section taken along the line 33 in Fig. 1.

Fig. 4 is a fragmentary section along the line 44 in Fig. 2.

Similar numerals refer to similar parts throughout the several views.

Referring in detail to the drawing, there is shown a loop base 10 of suitable insulating material, preferably one of the forms of plastic now being employed for such purposes.

Into the base In extend the ends H of a tubular loop l2 which is circular in form. Extending across the diameter of the loop l2 and axial- 1y into the base I!) is a brass center rod I3, one end of which is connected by means of a lead M l to a ground l5, and the other end of which passes through a slot 16 in the tubing l2 and is threaded to receive the lock nut I1 and the cap nut l8.

The purpose of the slot It is to permit the rod E3 to be moved toward either side of the center of the loop in order to provide an exceedingly delicate adjustment for the balancing of the loop thereby compensating for any errors which might arise due to the variations in the gauge and diameter of the tubing in the loop I2. This tubing is preferably of copper and the size and diameter of the loop depend upon the applicationlarger tubing and greater diameter of loop giving greater signal pick-up, and smaller tubing and smaller loop diameter giving less pick-up.

A matching circuit [9 to a conventional radio receiver 20 is also indicated.

While this loop is especially useful for radio compasses and similar instruments, no special application of the antenna is shown as the use of such devices is well understood.

Where the loop I2 is to be rotated, it is mounted on a revolvable base 2! such as are in common use on directional loops, and having a calibrated dial for angular measurements (not shown).

It is a well known fact that various forms of loop antenna have been constructed in the past. It is therefore not my intention to cover such devices broadly, but I do intend to cover all such forms and modifications as fall fairly within the appended claims.

I claim:

1.'An antenna of the class described consisting of a base of insulating material, a circular, upright antenna loop having its lower portion divided to form two spaced ends and having the ends thereof mounted in said base and having a grounded rod connecting the upper portion of said loop to said base and means for laterally adjusting the connection between said grounded rod and the uppermost portion of said loop.

2. A loop of the class described consisting of a circular metallic tube mounted in an upright plane, the lower portion of said tube being separated and the ends thereof mounted in a revolvable support of insulating material, a grounded rod extending vertically through the diameter of said loop from said support to the upper portion of the loop and means for adjusting the upper end of said grounded rod laterally toward either side of the center of said loop.

3. A device of the class described consisting of a revolvable base of insulating material, a vertical grounded rod mounted in the top of said base, a circular loop of tubular metal mounted in a vertical plane having the lower portion thereof divided and mounted in said base, and having the upper portion thereof attached to the upper end of said grounded rod, with the grounded rod substantially along the vertical diameter of the loop and means for adjusting the relationship between said grounded rod and loop.

WALTER O. SPOON.

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