12 and 17 meter adapter assemblies

12 and 17 meter adapter assemblies for a vertical antenna which includes an air wound inductance coil and winged capacitor straps. The adapter assemblies include a coil and wing capacitor straps at one end of the coil where the one end of each coil connects to the antenna and the other end of each coil, including the wing capacitor straps, mechanically connects to the antenna and is electrically insulated from the antenna.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to an assembly for a vertical antenna, and 
more particularly, pertains to a 12 and 17 meter adapter assemblies for a 
vertical antenna, such as a ten band vertical antennas or for a beam 
antenna. 
2. Description of the Prior Art 
Prior art antennas, especially vertical antennas, utilized strapped coils 
which have been inefficient and nonpractical. 
The assignee of the present invention has designed a series of antennas 
which utilize air inductance coils and capacitor assemblies which enhance 
radiation with negligible (zero) losses. 
The prior art antennas have utilized various assemblies to resonate 
vertical antennas on various frequencies which has caused loss in the 
antennas, and have been ineffective in radiation. 
The present invention overcomes the disadvantages of the prior art by 
providing an air inductance-capacitive adapter assembly which resonates an 
antenna, such as a vertical antenna or beam antenna, on predetermined 
frequencies with negligible (zero) loss. 
SUMMARY OF THE INVENTION 
The general purpose of the present invention is to provide an adapter 
assembly for a vertical antenna or a beam antenna which causes the 
radiators below the assembly to resonate as a monopole. 
According to one embodiment of the present invention, there is provided an 
add-on adapter assembly for a vertical antenna or beam antenna including a 
bracket for securing to the antenna, a coil of a predetermined number of 
turns, at least one capacitor wing strip connected to the coil, the end of 
the coil on the wing strip connected to an insulator, and the insulator 
connected to an element of either the vertical antenna or the beam 
antenna. 
Significant aspects and features include a 12 and 17 meter adapter 
assemblies which can either be an add-on assembly or an original 
manufacture assemblies. 
Other significant aspects and features of the present invention include an 
add-on adapter assembly for use at any predetermined frequency. 
Having thus described the embodiments of the present invention, it is a 
principle object hereof to provide a 12 and 17 meter adapter assemblies 
for a vertical antenna, such as for a vertical antenna the subject matter 
of U.S. Pat. No. 4,442,436, assigned to the same assignee of this patent. 
One object of the present invention is an assembly for a vertical antenna 
or a beam antenna.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a front view of a 12 meter adapter assembly 210 and a 17 
meter adapter assembly 12 of FIG. 3 of the present invention for a 
multi-band vertical antenna 216, such as the subject matter of U.S. Pat. 
No. 4,442,436. The 12 meter adapter assembly 210 and the 17 meter adapter 
assembly 212 are similar in construction and attach to the vertical 
antenna 214 as illustrated in FIG. 3. 
The 12 meter adapter assembly 210 is now described in detail. The air wound 
coil 215 of n turns is concentrically aligned over and about the vertical 
antenna member 216. A lower clamp 218 mechanically and electrically 
connects and secures between the bottom of air wound coil 215 and the 
vertical antenna member 216 with appropriate nut and bolt assemblies 19. 
An upper clamp 220 also connects and secures to the vertical antenna 
member 216 slightly above the top of 12 meter adapter assembly 210 with 
appropriate nut and bolt assemblies. A plastic insulator 222 secures to 
the upper clamp 220 with a nut and bolt assembly 224 and extends 
downwardly to meet the top of the 12 meter adapter assembly 210 where it 
secures thereto by a nut and bolt assembly 226. At least one horizontally 
aligned aluminum wing strip 228 secures electrically and physically to the 
top of the 12 meter adapter assembly 210 by the nut and bolt assembly 226 
as illustrated in FIG. 2. 
The 17 meter adapter assembly 212 is constructed and attached in the same 
manner, where the 17 meter adapter assembly 212 has more turns and the 
aluminum strip 230 is longer in length to effect antenna resonance at 17 
meters. 
FIG. 2 illustrates a side view of a adapter assembly for an antenna where 
all numerals correspond to those elements previously described. 
MODE OF OPERATION 
FIG. 3 illustrates a plan view of a vertical antenna of U.S. Pat. No. 
4,442,436 incorporated herein by reference with the 17 meter adapter 
assembly 212 and the 12 meter adapter assembly 210, wherein the 
description of FIG. 3 with reference numerals 10-138 can be found in the 
above patent. 
The 17 and 12 meter assemblies consist of airwound inductance-capacitor 
inserted just above the upper end of the 30 meter coil of U.S. Pat. No. 
4,442,436. 
Attach the long aluminum strip to the bolt that fastens the 17 meter coil 
(the larger of the two units) to the plastic insulator between the coil 
and the upper clamp. Use a flat washer, a lock washer and a hex nut. 
Attach the short aluminum strip to the 12 meter unit in the same way. 
These strips provide some of the circuit capacitance to resonate the two 
coils. Remove the upper portion of the antenna above the 30 meter coil. 
Loosen the #10 hex nuts on the bottom clamp and the wing nut on the upper 
clamp of the 17 meter assembly, the insulated end up, and slide the 
assembly over the upper end of the "HF6V" antenna. Slide the unit down 
until the lower clamp rests on the upper clamp of the 30 meter coil. 
Tighten the hex nut and stretch the coil so that the distance between the 
upper edge of the lower clamp and the lower edge of the upper clamp is as 
shown to the right. Install the 12 meter unit in the same way, so that the 
lower edge of the lower clamp is about two inches above the upper clamp of 
the 17 meter unit. Replace the upper section of the antenna and tighten 
all hardware. 
If mounted at ground level, the antenna should be operated over a number of 
radial wires, each at least as long as the antenna is tall, in order to 
reduce the ground loss resistance, and thus, the feedpoint impedance to an 
acceptably low value. In above-ground installations, at least two resonant 
radials at 180.degree. should be used per band. The length of a 
quarter-wave radial for 17 meters is 13 feet 4 inches, and 9 feet 3 inches 
for 12 meters. 
Feed a few watts of power to the antenna on 17 meters and note the 
frequency at which the SWR is lowest. Normal bandwidth is from 150 to 175 
kHz for SWR of 2:1 or less. To move the SWR curve to a higher frequency 
range loosen the wing nut on the upper coil clamp and stretch the coil 
about 1/4" at a time. To move the SWR curve to a lower frequency range, 
compress the coil a like amount at a time. 
Similarly, apply a few watts of power to the antenna on 12 meters where SWR 
bandwidth should be greater than 200 kHz. Stretch the 12 meter coil in 
increments of 1/4" or so to raise the tuning range or compress the coil a 
like amount to lower the tuning range. 
For very small upward frequency changes on both 17 and 12 meters, the 
capacitive loading strip at the upper end of each coil may be bent a few 
degrees off a straight line. This is equivalent to stretching the coil. In 
general, however, it will be easier to stretch or compress the coils 
rather than adjust the loading capacitance. 
SWR on both 17 and 12 meters should be less than 2:1 at resonance, though 
the exact SWR at resonance on any band will depend on the quality of the 
antenna's ground system. If SWR is not sufficiently below 2:1 on 17 
meters, connect the short length of coaxial line provided across the 
antenna feedpoint. This may improve the match on 17 meters at the cost of 
a slightly higher SWR at resonance on 15 meters. 
Various modifications can be made to the present invention without 
departing from the apparent scope hereof.