Vertical antenna

A ten-band vertical antenna includes completely automatic band switching for the amateur radio frequencies of eighty, seventy-five meters, forty meters, thirty meters, twenty meters, seventeen meters, fifteen meters, twelve meters, ten meters and six meters. The vertical antenna has a low angle of radiation and a low standing wave ratio on all frequencies which provides for direct coaxial cable transmission line feed. The seventy-five-meter, a switchable eighty-meter, and forty-meter inductor-capacitors are in parallel, while the thirty-meter inductor-capacitor is in series with a portion of the forty-meter circuit thereby providing inductive reactance for operation on eighty meters, seventy-five meters, forty meters, and thirty meters with a series inductor-capacitor connected between an upper vertical radiating element and the forty-meter inductor while permitting simultaneous resonance on each of the three higher frequencies of twenty, fifteen and ten meters. The entire radiator length of the vertical antenna is acitve on all frequencies except for fifteen and six meters where the upper portion of the antenna is decoupled above an end of a fifteen or six-meter quarter-wave decoupling stub. The seventeen- and twelve-meter circuits provide for decoupling so that the entire radiator length of the vertical antenna below these circuits is active. A coaxial relay can be switched to change between seventy-five meters and eighty meters operation by switching in an inductor-capacitor circuit for eighty meter operation. A six meter stub connects about the vertical section adjacent the fifteen meter stub connection.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to an antenna, and more 
particularly, pertains to a high-frequency vertical antenna for ten bands 
of operation and also with a 160-meter (1800 KHz) add-on adaptor for 
eleven bands of operation. 
2. Description of the Prior Art 
Those concerned with antennas have long recognized the need for a 
high-frequency vertical antenna including automatic band switching for all 
band amateur usage. The present invention fulfills this need. 
The traditional prior art vertical antennas have relied on anti-resonant 
inductor-capacitor circuit traps placed at or near the quarter-wave 
current antinode points to decouple varying lengths of the available 
radiating structure on those bands where the total height of the vertical 
antenna was greater than an electrical quarter wavelength. The approach 
provided that the overall height of the radiating structure was typically 
less than a quarter wavelength at the lowest frequency of operation and 
the exact height was largely determined by the inductance-capacitance 
ratio of the traps. The usual method of providing eighty-meter resonance 
in vertical antennas was to utilize a high inductance coil at the top of 
the structure which simultaneously served as a forty-meter decoupling trap 
and as a loading for eighty-meter resonance. In most designs, additional 
loading in the form of capacity hats was used to limit the overall height 
of the structure to something less than one-eighth wavelength on the 
lowest frequency. The physical height of the active radiating sections was 
usually less than a quarter wavelength because of the inductive reactance 
of the several decoupling traps at frequencies below the frequencies to 
which the decoupling traps were tuned. 
The prior art vertical antennas have had a number of limitations. First, 
the active antenna height on all but the highest frequency band was 
necessarily less than one-quarter wavelength resulting in a radiation 
resistance which progressively decreased from a high impedance on the 
highest frequency of operation. Second, the use of numerous traps and 
other loading devices increased the system Q and unnecessarily restricted 
the band width, especially on the mid-range HF (high frequency) 
frequencies where the active radiator height would be less than that 
required for unloaded resonance operation. Third, from a mechanical 
viewpoint, the use of numerous traps and loading devices in the upper 
sections of the vertical antenna made for a relatively unstable and heavy 
structure which required heavy and expensive construction for a 
freestanding wind survival rating. Fourth, a further difficulty had to do 
with the ease of adjustments for resonance at the desired frequencies in 
the low HF frequencies. Inasmuch as adjustment in the past for these 
frequencies had to be made in the upper sections of the antenna, the 
entire vertical antenna had to be removed from its mounting and brought to 
ground level for the slightest readjustment. This was a particularly 
inconvenience feature of operation as the effective operating band width 
of the vertical antenna was generally less than three percent of the 
authorized band spectrum. 
A patent entitled "Vertical Antenna with Decoupling Sections for Multiband 
Operation", U.S. Pat. No. 4,630,060, issued Dec. 16, 1986, to Newcomb 
describes an antenna for eight bands of operation. 
The present invention provides a vertical antenna that overcomes all the 
disadvantages of the prior art vertical antennas and provides for ten 
bands of operation, particularly in the amateur frequencies or eleven 
bands of operation with an add-on adapter for 160-meter operation for 
eleven bands of operation. 
SUMMARY OF THE INVENTION 
The general purpose of this invention is to provide a high-frequency 
vertical antenna which is resonant on eleven amateur radio HF bands or 
eleven HF frequencies with the use of a one hundred-sixty meter add on 
unit. 
According to one embodiment of the present invention, there is provided a 
high-frequency vertical antenna for use on the amateur radio 
high-frequency spectrum segments having an insulated seventy-five-meter 
supported section and including an adjustable parallel inductor-capacitor 
connected across the section, a switchable L/C circuit for eighty meters, 
an insulated forty-meter supported section connected to the 
seventy-five-meter section and including an adjustable parallel capacitor 
inductor connected across the section, a thirty-meter series 
inductor-capacitor connected between the forty-meter inductor and above 
the forty-meter inductor to a point on an upper radiating section, a 
seventeen-meter circuit connected across the mid-portion of the vertical 
element, a twelve-meter circuit connected across a mid-portion of the 
vertical element above the seventeen-meter circuit, and an upper vertical 
radiating section including a fifteen-meter quarter-wave stub section 
connected to the vertical radiating section whereby the overall antenna 
height is resonated on eighty and forty meters. The vertical antenna 
resonates as a quarter wavelength on thirty meters and twenty meters, the 
vertical antenna resonates as a quarter wavelength on fifteen meters on 
account of decoupling of the upper vertical radiating section of the 
antenna by the fifteen-meter stub section, and the vertical antenna 
resonates as three-quarters wavelength on ten meters. A six meter quarter 
wave stub is connected to the vertical section about the vertical element 
length adjacent the fifteen meter stub to resonate as a quarter wave 
length on six meters. 
One significant aspect and feature of the present invention is a vertical 
antenna which is omnidirectional including inherent automatic band 
switching for operating on ten HF amateur frequencies (including a one 
hundred sixty meter add on unit) of one hundred sixty meters through six 
meters with an additional switch in an L/C circuit for seventy-five or 
eighty meter frequency coverage. 
Another significant aspect and feature of the present invention is either 
parallel or series L-C circuits for loading and resonance of the structure 
for operating at predetermined frequencies of eighty-, seventy-five-, 
forty-, thirty-, twenty-, seventeen-, fifteen-, twelve-, ten-, and 
six-meter band segments. A one hundred sixty meter add on section can also 
be utilized to provide an additional band of operation. 
Having briefly described one embodiment of the present invention, it is a 
principal object hereof to provide a vertical antenna for operation on the 
high-frequency amateur radio frequencies of eighty meters through six 
meters and operation on one hundred sixty meters with an add on adaptor. 
The frequency segments are eighty meters, seventy-five meters, forty 
meters, thirty meters, twenty meters, seventeen meters, fifteen meters, 
twelve, ten and six meters. While the present invention has been disclosed 
for use on ten amateur radio frequency segments of the high-frequency 
spectrum, the specification is not to be construed as limiting of the 
present invention, as the principles of operation can be extended to any 
ten HF frequencies of operation or more as predetermined, or eleven 
frequencies when using a 160-meter adapter. 
One object of the present invention is a vertical antenna which operates on 
all of the amateur radio HF spectrum assignments as set forth by the 
Federal Communications Commission, and requires no manual band switching 
when changing frequencies and also provides for band changing to eighty 
meters. The band switching is inherently electrical in the figurative 
sense, in that the entire height of the vertical antenna radiates on all 
frequencies except for fifteen meters where the upper portion of the 
antenna is automatically and electrically decoupled for quarter wavelength 
operation on fifteen meters in the first embodiment. The automatic and 
electrical band switching eliminates the need for manual band switching 
from the physical antenna itself or from a remote point and does include a 
switching circuit for operation on the eighty meter band. The teaching for 
the frequencies of this antenna are applicable to current and future FCC 
amateur radio frequency segments, or for any predetermined frequency 
segments. 
Another object of the present invention is to provide a vertical antenna 
with no traps and fewer tuned circuits than the prior art vertical 
antennas, thus simplifying the vertical antenna with resultant economies 
in time and construction materials. By utilizing resonator 
inductor-capacitor sections, no decoupling traps are required. 
A further object of the present invention is to provide a vertical antenna 
having greater efficiencies because of longer active radiating sections of 
the upper high-frequency spectrum segments. Consequently, the band width 
is substantially increased for high-frequency spectrum segments because of 
the lower Q of the longer radiating sections and top loading for each of 
the spectrum segments. 
An additional object of the present invention is to provide a vertical 
antenna which provides readily accessible in-place adjustment on the 
thirty-, forty-, seventy-five-, and eighty-meter band where the Q is the 
highest. 
Still an additional object of the present invention is to provide a 
vertical antenna which has small wind loading because the principal 
frequency control circuits are mounted on the lower half of the vertical 
antenna. The upper half of the antenna only needs to support little or 
more than its own weight thereby being much lighter and requiring very 
small diameter metal tubing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1, which illustrates a vertical plan view of a vertical antenna 10, 
the present invention, shows a hollow tubular metal mounting post 12 
having a solid rod fiberglass insulator 14 of a diameter which telescopes 
internally into the mounting post 12, and secures thereto with a 
nut-and-bolt assembly 16. A seventy-five meter parallel inductor-capacitor 
metal section 18 has a lower hollow tubular portion of a diameter which 
telescopes over the solid insulator 14 and secures thereto with a 
nut-and-bolt assembly 20. A seventy-five-meter inductor coil 22 clamps 
between a top portion of the seventy-five-meter resonator capacitor 
section 18 to a mid-position on an insulator rod 24 as later described 
which telescopes into the section 42 and is secured thereto with a 
nut-and-bolt assembly 23 through hole 44 as illustrated in FIG. 2. A nut 
and bolt assembly 27 secures through the upper portion of the 
seventy-five-meter resonator capacitor section 18 and through a hole 25 in 
the insulator rod 24. Coil clamp 26 surrounds the mid-portion of the 
insulator 24 above the section 18, and a clamp 28 positions below the 
insulator rod 24 on the section 18, respectively, and each secures thereto 
with nut-and-bolt assemblies in addition to securing the respective ends 
of the coil 22 between coil clamps 26 and 28, as later described in FIG. 
2. A ceramic capacitor 30 secures to one side of conductor bracket 32 with 
a screw 34 and a bracket 36 secures to the other side of the capacitor 30 
with a screw 38 and to the section 18 with a hose clamp 40. 
An eighty-meter resonator section 200 includes an inductor coil 202, in 
parallel with a ceramic capacitor 204, secures to the seventy-five meter 
resonator capacitor section 18 below hose clamp 40. A bracket 208 is 
secured over the seventy-five-meter resonator section by a nut and bolt 
assembly 210. The other end of bracket 208 secures over a solid rod 
fiberglass insulator coil support 212 by a nut and bolt assembly 214. 
Conductors 216 and 218 secure to opposing sides of the ceramic capacitor 
204. Conductor 216 and the upper end of the inductor coil 202 secure 
physically and electrically beneath the portion of the bracket 208 secured 
by the nut and bolt assembly 214. A clamp 220 secures over lower end of 
the solid fiberglass insulator coil support 212 and secures thereto by a 
nut and bolt assembly 222. The lower end of conductor 216 and the lower 
end of the eighty-meter inductor coil 202 are electrically connected 
together under clamp 220. A conductor 224 connects between clamp 220 and 
to a relay contact 226 of a coaxial relay 228. An electrical power source 
230 and a switch 232 energize the coaxial relay 228. The center conductor 
234 of coaxial cable 138 is connected to the relay common arm contact 236. 
When the coaxial relay 228 is energized by the switch 232 and power source 
230, the center conductor 234 of the coaxial cable 138 connects to contact 
226 of the relay 228 and to the lower portion of the parallel inductor and 
capacitor 202 and 204 circuit to electrically change the resonance of the 
antenna 10 to eighty meters. When the relay 228 is deenergized, the center 
conductor 234 of the coaxial cable 128 is routed through conductor 238 and 
the parallel inductor and capacitor 202 and 204 are switched out of the 
circuit to allow an antenna resonance frequency of seventy-five meters, as 
well as other frequency bands ranging from forty meters to six meters as 
described herein. 
A forty-meter parallel inductor-capacitance metal section 42 has a hollow 
tubular lower portion of a diameter that telescopes over the insulator 24 
and secures thereto with a nut-and-bolt assembly 23 through hole 44. A 
forty-meter resonator coil 46 clamps between a mid-portion of the 
forty-meter section 42 to a bracket 32 at the insulator rod 24, as later 
described. Coil clamp 48 surrounds the mid-portion of the forty-meter 
section 42 and secures thereto with nut-and-bolt assemblies in addition to 
securing the respective end of the coil 46. A ceramic capacitor 50 secures 
to one side of the bracket 32 with a screw 52. A conductor 54 secures to 
the other side of the ceramic capacitor 50 with a screw 56 and to the 
section 42 with the hose clamp 58. 
A clamp 60, including two nut-and-bolt assemblies 62 and 64 secure a 
tubular stand-off insulator 66. A short metal tube 68 telescopes over the 
insulator 66 and secures thereto with a screw 70. A coil 72 connects 
between a second clamp 74 with a nut-and-bolt assembly 76, the clamp 74 
securing to the metal tube with nut-and-bolt assembly 78. A ceramic 
capacitor 80 secures with a bracket 82 and screws 84 and 86 between the 
tube 68 and the capacitor 80. An alligator clip 88 secures to a wire or 
braid 90 which secures with a screw 92 into the other end of the capacitor 
80. 
A lower end of a first metal section of hollow tubing 94 is of a diameter 
which telescopes into the top portion of the forty-meter resonator section 
42 and secures thereto with a self-tapping screw 96. A lower end of a 
second metal section of a hollow tubing 98 is of a diameter which 
telescopes into the top portion of the first metal section 94 and secures 
thereto with a self-tapping screw 100. A lower end of a third metal 
section of hollow tubing 102 is of a diameter which telescopes into the 
top portion of the second metal section 98 and secures thereto with a self 
tapping screw 104. A lower end of a fourth metal section of hollow tubing 
106 is of a diameter which telescopes into the top portion of the third 
metal section 102 and secures thereto with a self-tapping screw 108. A 
lower end of the fifth metal section 116 is of a diameter which telescopes 
into the fourth metal section 106 and secures thereto with a self-tapping 
screw 112. A lower end of a sixth metal section 114 is of a diameter which 
telescopes into a slotted top portion of the fifth metal section 116 and 
secures thereto with a hose clamp 118. A fifteen-meter stub assembly 120 
electrically and physically connects to the fifth section 116, as now 
described in detail. 
The 21 MHZ-15 meter stub assembly 120 includes a metal conductor strap 122 
electrically and physically secured to the fifth metal section 116 by a 
nut-and-bolt assembly 124. A metallic braid 126 wrapped around a 
nut-and-bolt assembly 128 extends downwardly parallel to the fifth through 
third sections 116-102. Plastic standoff insulators 130-134 physically 
space the stub assembly 120 from the upper portion of the vertical antenna 
10. The bolt 128 electrically and physically secures the braid 126 to tube 
116 via the metal strap 122. 
A 18-MHz-17 meter section 150 includes a lower clamp 152, an upper clamp 
154 and a rod clamp 156. An inductor rod 158 acts as an inductor while 
capacitor 160 connects between the right-angle bends 154a and 156a of the 
respective clamps. Bolts 162 and 164 secure the capacitor 160 to the right 
angle members through respective holes. Each of the clamps 152-156 include 
overlapping portions 152a, 152b, 154b and 156b which encompass the 
circular sections of the tubing rod, and are secured with appropriate 
nut-and bolt assemblies 166, 168, 170 and 172. The rod 158 is 3/16" by way 
of example and for purposes of illustration, while the clamp width is 
approximately 1/2".times.3.5" for the lower clamp and with like spacing 
between the rod and the tubing between the upper clamp, the capacitor 
bracket and the rod. The distance between the lower clamp and the upper 
clamp-capacitor bracket is 124" from the bottom of the antenna to the 
lower bracket and 142.75" from the bottom of the antenna to the upper 
bracket. The rod length is approximately 24". 
A 24 MHz-12 meter assembly 180 includes a like lower clamp 182, an upper 
clamp 154 and a capacitor clamp 156. A vertical inductor rod 188 connects 
between the clamps 182 and 156, and a capacitor 190 connects between 
right-angle portions 154a and 156a with bolts 192 and 194. Suitable 
nut-and-bolt assemblies are provided for the wrap-around portions of each 
respective clamp, accordingly, as previously described with respect to the 
lower 18 MHz-17 meter circuit. The rod length of 3/16" rod is 
approximately 36" with center-to-center spacing of 31/2". The separation 
of the clamps from the base of the antenna is the difference between 
157.75" and 183". Both capacitors are the bathtub ceramic variety of 
approximately 67 picofarads. The sections add little or no apparent 
loading at frequencies below the resonant frequencies of the decouplers 
and provide an equivalent series circuit of an L-C parallel combination. 
An impedance matching coil 136 connects between the nut-and-bolt assembly 
20 in the bottom of the seventy-five-meter section 18, and the 
nut-and-bolt assembly 16 at the top of the hollow tubular mounting post 
12. A matching section length of seventy-five ohm coaxial cable 
transmission line 138 connects in parallel across the impedance matching 
coil 136 and terminates in a suitable coaxial plug such as PL-259. An 
electrical ground connects to the nut-and-bolt assembly 16, and the hollow 
tubular metal mounting post 12. The metal portions of the vertical antenna 
10 can be aluminum tubing of predetermined diameter, while the insulators 
can be fiberglass, polyethylene, etc., by way of example and for purposes 
of illustration as later described. 
Sections 150 and 180 for the 17-meter and 12-meter circuits and a six meter 
stub assembly 250 can be positioned on the vertical section at any 
suitable assembly stage. The assembly of the clamps is similar to that of 
the clamps for the 30-, 40- and 75-meter circuits, especially with respect 
to the inductor rod and the capacitor. The clamps are assembled to the 
inductor rod, the capacitor is secured to the one clamp, and the other 
capacitor clamp is secured thereabout whereupon the whole assembly is 
secured to the vertical radiating section at the appropriate dimensions as 
previously set forth. The particular sections and resonance are obtained 
by adjusting the clamps and sections over the length of the vertical 
radiation sections 42-114. 
A 50-MHZ six meter stub assembly 250 includes a double ended metal clamp 
252 electrically and physically secured to the fourth metal section 106 by 
a nut and bolt assembly 254. A stub rod 256 spaced a fraction of a wave 
length from the fourth and third metal sections 106 and 102 is secured 
physically and electrically in one end of the double ended metal clamp 252 
by a nut and bolt assembly 258 and extends downwardly and parallel to the 
third and fourth metal sections 102 and 106 and is secured to the third 
metal section 102 by an insulated clamp 260. The insulated clamp 260 
includes brackets 262 and 264. Nut and bolt assemblies 266 and 268 tighten 
the brackets 262 and 264 over the stub rod and the third metal section 
102, respectively. 
FIG. 2, which illustrates a sectional view taken along line 2--2 of FIG. 1, 
shows the seventy-five-meter section 18, the forty-meter section 42, and 
the thirty-meter inductor capacitor section 68. Particular attention is 
drawn to the seventy-five-meter inductor 22 and the seventy-five-meter 
capacitor 30, the forty-meter inductor 46 and the forty-meter capacitor 
50, and the thirty-meter inductor 72 and the thirty-meter capacitor 80. 
While the seventy-five- and forty-meter circuits are parallel LC circuits, 
the thirty-meter circuit is a series LC circuit. While the embodiment is 
for 75, 40, and 30 meter high frequency spectrum segments, this is by way 
of example and for purposes of illustration only, and is not to be 
construed as limiting of the present invention. All other numerals 
correspond to those elements previously described. 
The coils of FIG. 2 are four-inch nominal diameter and are wound of 
aluminum tie wire or like wire. Coil 22 is seventeen turns, coil 46 is 
eight turns and coil 72 is nine turns. The capacitors 30, 50, and 80 are 
ceramic capacitors and are 200 pfd, 67 pfd and 67 pfd, respectively, by 
way of example and not to be construed as limiting. 
MODE OF OPERATION 
The mounting post 12 of FIG. 1 is set into a suitable hole, approximately 
in the range of twenty-one inches deep, so that the upper end of the 
insulator 14 clears the ground by a couple of inches. The earth is packed 
tightly around the mounting post, and concrete can be utilized for 
additional strength. 
A No. 8 13/4" bolt 16 passes through the braid lug of the coaxial cable 
impedance matching transmission line 138, through a flat washer, through a 
lower loop of the impedance matching coil 136, through another opposing 
flat washer, through the hole in the mounting post 12 and the insulator 
14, and secures with a flat washer, a lock washer, and a No. 8 nut. The 
seventy-five-meter resonator coil 22 has two clamps 26 and 28. A bolt 
assembly is removed from clamp 28 and the clamp 28 spread slightly apart. 
The top of seventy-five-meter resonator section 18 is first passed through 
the large clamp 28, the seventy-five meter resonator coil 22, and then 
through the clamp 26. The screw hole in the clamp 26 of seventy-five-meter 
resonator coil 22 is aligned with the lower screw hole in the top of 
section 18, and secured with nut-and-bolt assembly through the clamp 26 
into the insulator 24. The 1/4" by 1" bolt is loosened in the clamp 28, 
and the large clamp 28 is slid down the seventy-five-meter section 18 to a 
predetermined position. Subsequently the clamp 28 is tightened. The 
forty-meter resonator coil 46 is installed on the forty-meter section 42 
in a like manner, and tightened at a predetermined position. 
The lower end of first metal section 94 telescopes onto the top of 
forty-meter section 42. The screw holes are aligned in the sections 94 and 
42, and secure with a No. 10-24 self-tapping screw 96. The bottom of 
second metal section 98 telescopes into the top of first metal section 94, 
and the screw holes are aligned and secured with a No. 10-24 self tapping 
screw 100. A third metal section 102 telescopes into the second metal 
section 98 and the screw holes are aligned and secured with a No. 6-32 
self-tapping screw 104. The fourth metal section 106 telescopes into the 
third metal section 102, and the screw holes are aligned and secured with 
a No. 6-32 self-tapping screw 108. The fifth metal section 116 telescopes 
into the fourth metal section 106 and the screw holes are aligned and 
secured with a No. 6-32 self-tapping screw 112. The sixth metal section 
114 telescopes into slotted end of section 116, and is secured with the 
small stainless steel hose clamp 118. The braid 126 connects to metal 
strap 122, secured by screw 128, and is supported at insulators 130-134. 
The insulators 130-134 can be slotted for accepting the braid. Any excess 
braid can be wrapped around the lower insulator 134. 
The bottom of the seventy-five-meter resonator capacitor section 18 is 
positioned over the top of the mounting post 12, and the screw holes 
aligned. A No. 8 .times.13/4" bolt 20 passes through the center lug of the 
coaxial cable impedance matching transmission line 138, through a flat 
washer, through the upper loop of the impedance matching coil 136, through 
another opposing flat washer, through the sections 18 and 14, and secures 
with a flat washer, a lock washer, and a No. 8 nut. The assembly of 
sections 42-114 is raised and positions atop by telescoping the bottom of 
the forty-meter section 42 over the top of the insulator 24, aligning the 
screw holes, and securing with a No. 10-24 self-tapping screw 23. 
The vertical antenna 10 produces very low-standing wave ratio (SWR) 
readings over the twenty-, fifteen-and ten-meter bands, and the eighty-, 
seventy-five-, forty- and thirty-meter resonator circuits are 
predetermined and set for resonances of approximately 3500, 3700, 7100, 
and 10,100 KHz. Inasmuch as some variation can be expected, the following 
procedure is utilized to adjust the vertical antenna 10 for minimum SWR at 
any desired point in each of the ten bands of the HF spectrum. SWR 
readings can be taken at the transmitter end of the coaxial cable 
transmission feedline, or at the junction of the coaxial cable 
transmission feedline, or at the junction of the coaxial cable 
transmission feedline which is fifty-two ohm and the seventy-five ohm 
impedance matching transmission line 138 for preferred SWR. 
The frequency of minimum SWR on fifteen meters is predetermined. To raise 
the frequency, the length of the braid 126 is decreased. The length of the 
assembly 120 is one-quarter wavelength or, nominally, twelve feet in 
length. The frequency of minimum SWR on twenty meters is predetermined. To 
raise or lower the frequency, the total length of sections 94 through 114 
is adjusted by varying the amount of overlap between sections 116 and 114 
a few inches. The frequency of minimum SWR on ten meters is predetermined. 
The twenty-meter adjustment also determines the ten-meter resonant 
frequency, but resonance on both bands is so broad that slight adjustments 
for the sake of improved SWR on one band do not significantly affect SWR 
on the other. The frequency of minimum SWR on forty meters is 
predetermined. Adjustment is made by loosening the upper clamp 48 of the 
forty-meter resonator coil 46, and compressing or expanding the spacing 
between coil turns to lower or raise the frequency respectively. One-half 
inch of travel will move the frequency of minimum SWR by approximately 
seventy KHz. When the proper setting has been determined, the clamp 48 is 
tightened in place. The frequency of minimum SWR on eight or seventy-five 
meters is predetermined. Adjustment is made in a like manner by 
respositioning the lower clamp 28 on the seventy-five meter resonator coil 
22. Adjustments can also be made to the switchable eighty meter coil 202 
to determine its best frequency from 3500-3700 KHZ. Likewise, adjustment 
to the thirty-meter coil 72 is made in a like manner with clamp 74. The 
clip 88 connects to the second or third turn of coil 46. The tap clip 88 
is connected as high as possible on coil 46 so as not to affect the 
twenty-meter resonance. When the proper setting has been determined and 
the lower clamp 28 is tightened, the impedance matching coil 136 is 
adjusted at the base of the vertical antenna 10 by spreading the turns 
farther apart or squeezing them closer together until the SWR drops to a 
minimum value. One adjustment of the impedance matching coil should 
suffice for operation over the entire 3700-4000 KHz range, provided that 
the necessary adjustments are made to the seventy-five meter resonator 
coil 22. In general, the thirty-, forty-, eighty meter and 
seventy-five-meter adjustments will not significantly affect adjustments 
previously made for twenty, fifteen, and ten meters. However, if the 
eighty meter and seventy-five meter tuning are readjusted for operation at 
a much higher or lower frequency, it may be necessary to readjust the 
thirty-or forty-meter tuning in order to maintain SWR or less than 2:1 at 
both band edges. 
The vertical antenna 10 is constructed of commercially available components 
including aluminum tubing of 3/8, 1/2, 5/8, 3/4 7/8 and 1 and 11/8 inch 
outer diameters of predetermined lengths, aluminum tie wire, fiberglass 
insulators and the like components. The aluminum tubing can be 0.058 wall 
6061-T6 leading to an antenna weight of less than ten pounds. The height 
of the antenna is approximately twenty-six feet. The eighty-meter 
resonator capacitor section 18 is four feet; the forty-meter resonator 
capacitor section 42 is one foot; and sections 94-114 are each 
approximately four feet. The fifteen-meter stub assembly 120 is tinned 
braid, but could be 3/16" rod or hollow tubing, or, in the alternative, 
can be made entirely of hollow tubing, or, in the alternative, can be made 
entirely of 3/16" rod joined together by a clamp. 
The vertical antenna 10 is easily capable of handing transmitter input 
power of 2000 watts SSB or 1000 watts CW. Fifty-ohm coaxial cable 
transmission line connects to the impedance matching section 138. The VSWR 
at resonance is less than 1.5:1 across the bands of operation. 
With regard to the inductor coil-capacitor structure, the 40-meter section 
is self-resonant near 30 meters. The series circuit resonance near 30 
meters effectively shorts out part of the 40 meter parallel circuit, thus 
changing its resonance during operation in the 30-meter range and thus 
allowing the entire structure to resonate at a quarter wavelength monopole 
in the same frequency range. 
It is important to note that the capacitor-inductor structure of either the 
80-, 75-, 40-, or 30-meter circuits can be adapted to other antennas such 
as beams or other vertical antennas. The theory of operation is an L-C 
reactance generating network to produce an additional resonance on an 
existing antenna. The capacitance shunt across a portion of the radiator 
forms a parallel resonant high impedance decoupling circuit. The 
inductance can be varied by either the distance of the capacitor straps or 
through an inductor. The resultant circuit formed is anti-resonant at a 
higher frequency. The circuit loads the radiator so that the radiator 
becomes resonant at some lower frequency, in which case the portion of the 
radiator above the capacitor can be shortened to restore the original 
resonance. In the alternative, the capacitance can be adjusted to resonate 
at a frequency below that of the desired second resonance, in which case 
the entire structure can be made to resonate at the desired higher 
frequency. 
Various modifications can be made to the vertical antenna of the present 
invention without departing from the apparent scope hereof. The resonance 
on segments of the high-frequency spectrum is predetermined for the 
desired frequency of operation and is not limited to the eighty-, 
seventy-five-, forty-, thirty-, twenty-, seventeen-, fifteen-, twelve- 
ten-, and six-meter band segments of the present invention which has been 
by way of example and for purposes of illustration only, and is not to be 
construed as limiting of the present invention.