Apparatus and method for a portable roll-out antenna

A portable roll-out antenna system which forms a compact, transportable assembly when not being used. The roll-out antenna system is provided with flexible antenna elements which are individually wound onto reels for storage and transportation, and rolled out for use as an efficient antenna system. Each pair of antenna elements is connected to a balun for proper connection to unbalanced connecting cables. The baluns are housed in an end-cap assembly upon which are mounted the antenna element reels when the antenna system is not being used. A power splitter allows more than one connecting cable to be electrically coupled to a remote transmitter/receiver by way of a transmission line. The power splitter is housed in a center reel assembly which is provided with a component to lockably receive part of the end-cap assembly upon which is mounted the antenna-element reels, thus holding the antenna-element reels together and forming a compact, transportable assembly.

BACKGROUND 
1. The Field of the Invention 
This invention relates to antennas, more particularly to a portable antenna 
system wherein the radiating antenna elements and associated conductors 
are carried on reels for storage and transportation, and wherein the 
entire antenna system can be rolled out for rapid deployment and use. 
2. The Prior Art 
The design and manufacture of antennas for radiating radio-frequency 
electromagnetic waves has been the subject of ongoing research ever since 
"wireless" communication was first demonstrated. This research has 
continued to the point where, today, a multitude of different antennas are 
available for a wide variety of applications. Likewise, the design of 
radio-frequency transmitting and receiving equipment has also been the 
subject of extensive research and development. This research, and the 
general trend toward miniaturization of electronic components, has allowed 
the design and manufacture of compact, portable radio transmitters and 
receivers. Many of these transmitters and receivers are capable of being 
operated virtually anywhere. Presently available portable radio equipment 
ranges in size from small hand-held transceivers that may be easily 
carried by a single person, to large units, operated by batteries or a 
small generator, which are capable of transmitting thousands of watts of 
radio-frequency energy. 
Portable transmitters and receivers have become indispensable in a wide 
variety of governmental and commercial applications. In particular, 
portable radio equipment has become an essential tool to police, rescue, 
and military organizations. For example, in military applications it is 
highly desirable to be able to move rapidly from one radio transmitting 
site to another as discretely as possible. Portable radio equipment 
available today generally is easily transported from one site to another. 
Antennas, as available previously in the art, however, have often been 
very difficult to move from site to site. Therefore, an antenna system 
which is compact and easily transportable, easily hidden, as well as 
operable in any weather or terrain, would be highly desirable. The 
antennas, however, that have been available in the art to the present time 
have generally presented several serious problems when used by 
organizations such as the military. 
The problems encountered in the use of antenna designs found in the prior 
art stem from the fact that the available antennas which were reasonably 
portable were generally less efficient than was desirable. Thus, the 
antenna designer was faced with the choice of designing a very portable 
antenna or an efficient antenna. Alternatively, in some cases portability 
could be achieved but the antenna became extremely complex in its 
construction and deployment, or cumbersome in size and weight, and thus 
took a substantial period of time to set up as well as presenting other 
difficulties. An examination of the approaches taken in the prior art 
demonstrates the difficulties encountered in designing an antenna that is 
portable and that efficiently radiates and receives radio signals. 
One approach taken in the prior art to provide an efficient portable 
antenna is to modify the design of a rigid-element antenna intended for 
use as a permanently installed antenna. This modification generally 
allowed the antenna to be disassembled for transportation from site to 
site. Furthermore, use of rigid elements in a portable antenna allows the 
antenna to be of a design similar to a permanently installed fixed-base 
antenna. Also, the use of a rigid-element antenna generally provides an 
antenna whose radiation pattern, directivity and standing wave ratio at a 
particular frequency, is independent of the physical surroundings in which 
it is operated. There are, however, several problems which accompany the 
use of rigid-element antennas for use as portable antennas. 
The first of these problems is that assembly and disassembly of a 
rigid-element antenna generally takes a significant amount of time and can 
also be quite complex. The fact that the antenna takes an extended length 
of time to assemble or deploy reduces its usefulness with a portable 
transmitter/receiver. Second, rigid-element antennas, even when 
disassembled, are often both bulky and heavy, making them difficult to 
transport. Alternatively, if the weight of the rigid-element antenna is 
lessened to ease transportation difficulties, the rigid elements of the 
antenna generally become more fragile requiring greater care in assembly, 
disassembly, transportation, and use. Third, a rigid-element antenna 
generally requires suspension above the ground for proper operation. This 
is usually done by mounting the antenna on a tall mast. The requirement of 
a mast further increases the difficulty of transporting and assembling the 
antenna system in addition to providing a very conspicuous marking as to 
the location of the transmitter/receiver. Such conspicuousness can be a 
great disadvantage in a military operation. Fourth, the radiation pattern 
of rigid-element antennas generally cannot be altered easily. Altering the 
radiation patterns of such antennas generally requires the reorientation 
of the rigid elements in relation to one another or reorienting the 
position of the entire antenna system, as well as other system 
alterations, all of which can be difficult with rigid-element antennas. 
The above considerations all mitigate against the use of a rigid-element 
antenna for use with portable radio equipment. 
Other types of antennas which have been used with portable radio equipment 
include single-element antennas often consisting of a single vertical 
element configured in a flexible "whip" manner. A single-element antenna 
provides some of the required portability, that is, ease of transportation 
and assembly, that is desired with portable radio equipment. Such 
antennas, however, have the drawback of not allowing a wide choice of 
radiation patterns and often are inefficient radiators and receivers of 
radio-frequency energy. While the above considerations are relevant to an 
antenna that is to be operated at any frequency, the above considerations 
become prominent in the design of an antenna that is to be operated in the 
high-frequency band, 3 MHz to 30 MHz, and lower frequency bands, such as 
the medium frequency band, 300 KHz to 3 MHz. 
At high and medium frequencies it becomes especially difficult to design an 
efficient antenna that is still reasonably portable. This can be 
appreciated by understanding the considerations that apply when 
determining the necessary length of a half-wave radiating element that is 
to be operated at 30 MHz. The shortest length of an antenna element which 
will resonate at a given frequency must be approximately equal to one-half 
wavelength of that frequency. A 30 MHz signal has a wavelength of 
approximately 10 meters. Thus, a half-wave antenna must be approximately 
five meters in length. It can be appreciated that a rigid antenna element 
five meters in length can present considerable difficulties when 
transported. These problems are compounded when designing a portable 
antenna for use at frequencies lower than 30 MHz. 
What is needed in the art is a portable antenna which is simple to 
transport and store as well as simple to deploy. Furthermore, it would be 
very advantageous to design a portable antenna which is capable of 
radiating high transit power efficiently as well as to allow easy 
alteration of the radiation pattern of the antenna. Still further, it 
would be an advancement in the art to design a portable antenna which is 
compact and lightweight and which is impervious to adverse weather 
conditions as well as easy to maintain. 
BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
The portable roll-out antenna of the present invention includes a plurality 
of reel assemblies and a mechanism for locking the reel assemblies 
together. In the presently preferred embodiment, four of the reel 
assemblies provide a grooved rim which is rotatably mounted on a support 
member. A flexible antenna element is wound upon each of the grooved rims 
during storage and transportation. The flexible antenna elements are 
rolled out from the grooved rims when setting up the antenna system. Each 
of the support members of the antenna element reel assemblies is provided 
with an opening, which may be used as a handhold while winding or 
unwinding the flexible antenna elements. A connecting cable reel assembly 
is provided having a fixed grooved rim upon which are wound suitable 
radio-frequency conductors such as coaxial cables. In the center of this 
reel assembly is mounted a connecting cable reel assembly housing. A power 
splitter is mounted in the housing. Connected to the power splitter are 
the coaxial cables as well as a single connector which is to be attached 
to a transmission line leading to a transmitter/receiver. The presently 
preferred embodiment is also provided with end-cap assemblies, each 
provided with the necessary components for connecting the coaxial cables 
to the flexible antenna elements which have been unwound from their 
respective reels. When the antenna elements and connecting conductors are 
rolled out and properly connected to one another, and to a radio 
transmitter/receiver, an efficient radio-antenna system is formed. By 
winding the elements and conductors onto their respective reels and 
inserting a portion of the end-cap assembly through the openings provided 
in the reels, and locking the end-cap assembly to the connecting reel 
assembly housing, a compact, lightweight, transportable package is formed. 
The angtenna system is then ready for transportation and storage until 
deployment of the antenna system is once again desired. 
It is therefore a primary object of the present invention to provide a 
compact, lightweight, transportable, and rapidly deployable antenna 
system. 
Another important object of the present invention is to provide a portable 
antenna system that efficiently radiates and receives radio signals. 
Another important object of the present invention is to provide a portable 
antenna system that is able to withstand the rigors encountered during 
portable use and adverse weather conditions. 
A further object of the present invention is to provide a portable antenna 
system which allows the convenient and rapid alteration of its radiation 
pattern. 
Another object of the present invention is to provide a portable antenna 
apparatus which is lightweight and efficient and yet allows radiation of 
substantial amounts of radio-frequency energy. 
A still further object of the present invention is to provide a portable 
antenna which may be discretely and inconspicuously deployed. 
These and other objects and features of the present invention will become 
more fully apparent from the following description and appended claims 
taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Reference is now made to the drawings wherein like parts are designated 
with like numerals throughout. 
The presently preferred embodiment of the present invention is generally 
designated at 10 in FIG. 1. It should be understood that the embodiment of 
the present invention described herein is only one of many possible 
embodiments that could implement the present invention without departing 
from the invention as claimed. The portable roll-out antenna generally 
consists of four antenna-element reel assemblies, generally designated 
14a14d, a connecting cable reel assembly, generally designated 16, and two 
end-cap assemblies, generally designated 12a-b. In FIG. 1, antenna-element 
reel assemblies 14a and 14b, connecting cable reel assembly 16, and 
end-cap assembly 12a have been separated, and are in a position to have 
their respective flexible antenna elements and conducting cables rolled 
out and the antenna systems set up for the transmission and reception of 
radio signals. Still referring to FIG. 1, antenna-element reel assemblies 
14c and 14d are stacked upon end-cap assembly 12b and are in the position 
that would be taken by these components during preparation of the antenna 
system for transportation from one site to the next. Antenna-element reel 
assemblies 14a-d are each identical in configuration one to another. 
Likewise, end-cap assemblies 12a and 12b are also mechanically identical. 
Thus, in the subsequent discussion, any description of one component also 
applies to a similar component. 
The construction of the antenna-element reel assemblies 14a-d can best be 
described by reference to FIGS. 3 and 3a. The structure shown in FIGS. 3 
and 3a is just one of many structures which could be adopted so as to 
provide a carrier means upon which to wind or store the antenna-element 
conductors. FIG. 3 is a front-elevated view of the antenna-element reel 
assesmbly of the presently preferred embodiment. The antenna-element reel 
assembly 14a comprises a reel 100 mounted on a support member 108, and a 
triangular opening 114 formed through the support member 108. The reel 100 
consists of a grooved rim 103, as can be seen best in FIG. 3 a, with 
extended side members 105 as illustrated in the partial cross section at 
the bottom of FIG. 3a. The dimensions of the grooved rim 103 and extended 
side members 105 are not critical but must be sufficient to allow the 
desired length of antenna element 118 to be carried on the reel 100. The 
length of antenna element 118 that must be carried by the grooved rim is 
generally determined by the lowest operating frequency at which the 
antenna will be operated. The antenna element 118 is held onto the grooved 
rim 103 by lugs 120 (see FIG. 3a) which is attached to the antenna element 
118. The lugs 120 are held securely to the grooved rim by a screw 122. The 
unattached end of the antenna element is formed into a loop 124, as can be 
seen in FIG. 1. A stopper 126, also observable in FIG. 1, is mounted on 
the antenna element adjacent to the loop 124. The stopper 126, when wedged 
between the opposing sides 105 of reel 100 holds antenna element 118 
tightly on grooved rim 103 so as to prevent it from becoming unwound until 
desired. 
Antenna-element reel 100 is equipped with a hinged handle 104 and a 
handle-securing mechanism 102. When hinged handle 104 is released from the 
handle-securing mechanism 102, the handle 104 may be used to facilitate 
selectively winding or unwinding the antenna element 118 onto, or off 
from, antenna-element reel 100. Furthermore, when handle 104 is held in a 
closed position by the handle-securing mechanism 102, the handle 104 
assists in preventing antenna element 118 from unwinding off from the reel 
100 in the event that the stopper 126 is jarred loose. 
The grooved rim 103 of the reel assembly 14a is supported by three roller 
bearings such as the one shown in the cutaway portion of FIG. 3a and 
designated 116. The support member 108 has two opposing flat sides 109. 
Each of the three roller bearings 116 is attached between opposing sides 
109 by a screw 110 as can be seen in FIG. 3. The diameter of the sides 109 
is chosen so that the sides 109 slightly overlap the extended side members 
105 of grooved rim 103 as shown in FIG. 3a. The portion of support member 
108 which overlaps the sides 105 of grooved rim 103 assists in keeping the 
grooved rim 103 in the proper position on the roller bearings 116 by 
limiting the grooved rim's lateral movement. 
Sides 109 of support member 108 are also provided with a plurality of holes 
112 which facilitates the cleaning of any dirt or debris that may 
accumulate between the opposing sides 109 of the support member 108. The 
triangular opening 114 formed through the center of support member 108 
provides a convenient handhold which may be used when rolling out the 
antenna element 118 or winding the antenna element 118 back onto the reel 
100 of assembly 14a. Furthermore, opening 114 cooperates with other 
components to provide a compact, transportable antenna system as will be 
explained below. 
The antenna elements 118 may be of any suitable material which has 
sufficient strength to withstand periodic flexing and winding. It is also 
desirable that the antenna elements 118 be corrosion resistant so as to 
avoid the loss of efficiency in the antenna system due to excessive 
corrosion on the antenna elements. The antenna element 118 of the 
presently preferred embodiment is fabricated from a bronze alloy wire with 
a polyvinylchloride (PVC) insulating jacket. Many wires, however, 
available in the art could also be used. Likewise, the remainder of the 
antenna-element reel assembly 14a may be constructed of any material which 
has sufficient structural strength to withstand with rigors of portable 
use. Because of its light weight and durability, aluminum is one preferred 
material from which to fabricate the reel 100 and support member 108. 
It can be appreciated that by utilizing a flexible, roll-out antenna 
element 118 many of the difficulties encountered in the prior art by the 
use of rigid antenna elements can be overcome. The use of a flexible, 
roll-out antenna element 118 allows for long elements to be wound upon the 
reels and compactly stored. Furthermore, the antenna may be configured so 
as to operate in various frequency ranges by winding out more or less of 
the flexible antenna element 118. An even further advantage of using a 
flexible, roll-out antenna element 118 is that the positions of the 
radiating elements relative to one another may be easily altered, thus 
providing a wider range of design in terms of beam pattern and 
directionality. 
The presently preferred embodiment of the invention also includes a 
connecting cable reel assembly generally designated at 16 in FIG. 1. As 
can be seen best in FIG. 4, the connecting cable reel assembly 16 provides 
a carrier means for cables 162-163 and is provided with a fixed grooved 
rim 150 upon which connecting cables 162 and 163 are wound. Rim 150 may be 
partially seen in the cutaway portions of FIG. 4. It should be appreciated 
that the structure shown in FIG. 4 is one of many structures which could 
be adopted so as to provide a carrier means upon which to wind or store 
the connecting cables 162-163. In the presently preferred embodiment, two 
connecting cables 162-163 are provided; however, this number could be 
varied according to the application and configuration of the portable 
antenna system. The grooved rim 150 must be of the appropriate size so 
that a suitable length of connecting cables 162 and 163 may be wound upon 
the grooved rim 150. The length of the connecting cables 162 and 163 will 
be determined by the particular configuration taken when the antenna is 
rolled out. In the presently preferred embodiment the connecting cables 
162 and 163 are coaxial cables of the type that are generally used in 
radio-frequency communication applications. One end of each of the cables 
is provided with a male "N" type coaxial connector 165, shown in FIG. 1, 
as is commonly available in the art. Mounted on the coaxial cable adjacent 
to the coaxial connector is a stopper 167 which when wedged between the 
opposing sides 151, as shown in FIG. 1 of the grooved rim 150, serves to 
hold the coaxial cables 162 and 163 tightly wound upon the grooved rim 
150. 
The grooved rim 150 of the connecting cable reel assembly 16 is mounted in 
a fixed position to the connecting cable reel assembly housing 152, as can 
be seen best in FIG. 4, rather than being rotatably mounted as are the 
grooved rims 103 of antenna-element reel assemblies 14a-d. A housing 152 
is also provided on reel assembly 16, as is shown in FIG. 4. The grooved 
rim 150 and housing 152 of the connecting cable reel assembly 16 is 
fastened together using screws, indicated at 156, placed about the housing 
152 and the inner perimeter of the grooved rim 150. 
The housing 152 is provided with a bore 170 as can be seen best in FIG. 4. 
The bore 170 is centrally located within the radius of the grooved rim 
150. Within the bore 170 there is provided a slot 172. The slot 172 may be 
configured so as to provide a continuous passageway from the first side of 
the housing 152 to the second side of the housing 152. Slot 172 cooperates 
with end-cap assemblies 12a-12b so as to provide a means for securing each 
reel assembly 14a-14d when they are mounted on the end-cap assemblies 
12a-12b as explained more fully below. 
The connecting cable reel assembly 16 may be fabricated out of any material 
suitable to withstand the rigors of portable use. The presently preferred 
material for fabrication of connecting cable reel assembly 16 is aluminum. 
Furthermore, it should be appreciated that the particular structure shown 
in the presently preferred embodiment is only one of many configurations 
which could perform the same function as the structure shown. 
The remainder of the electrical components associated with the connecting 
cable reel assembly 16 is shown best in FIG. 4. In the presently preferred 
embodiment a female "N" type coaxial connector 158, functioning as a 
transmission line connector, is mounted upon the surface of the connecting 
cable reel assembly housing 152. As shown in FIG. 1, connector 158 may 
include an attached cap 159. Further, the transmission-line connector 158 
is mounted on top of housing 152 (see also FIG. 1) so as not to increase 
the overall width of the assembly 16 beyond the width of the rim 150. When 
the antenna system of the present system is rolled out and configured for 
use in the transmission and reception of radio signals, the transmission 
line leading to the remote radio transmitter/receiver, or other radio 
component, is connected to transmission line connector 158. When used with 
the presently preferred embodiment, the transmission line should be 
terminated in a connector compatible with transmission line connector 158 
and also be of the unbalanced type such as a coaxial cable with its shield 
connected to ground. As will be appreciated by those who are skilled in 
the art of antenna design, other types of transmission lines and/or 
connectors could be utilized without departing from the invention as 
claimed. 
Referring again to FIG. 4, the transmission line connector 158 is connected 
to a power-splitter 160, which is partially shown in the cutaway portions 
of FIG. 4. In the presently preferred embodiment the power splitter 160 is 
of the two-way type. The power splitter 160 can be one of any type of 
power splitters which are well-known in the art of antenna design. 
However, attention must be paid to considerations such as power-handling 
capacity, operating frequency range, and physical size when choosing a 
power splitter for use in the present invention. 
Coaxial cables 162 and 163 are directly connected to the power splitter 
160. Coaxial cables 162 and 163 pass through the grooved rim 150. At the 
point where the coaxial cables 162 and 163 pass through the grooved rim 
150, grommets, indicated at 166, are positioned around coaxial cables 162 
and 163 so as to prevent damage to the cables. Furthermore, strain 
reliefs, indicated at 164, are provided for each of the cables, though 
only one strain relief is shown in the cutaway portion of FIG. 4, to 
prevent excessive tension from being exerted on coaxial cables 162 and 163 
at the point where they pass through grooved rim 150. Filler material 168 
is provided in the cavity of connecting cable reel assembly housing 152. 
The filler material in the presently preferred embodiment is a 
silicon-based resilient material such as that known in the art as RTV. By 
the particular configuration shown for a conducting cable reel assembly 
16, a compact unit is formed upon which the cables necessary to connect 
various antenna elements may be carried, in addition to providing a way of 
carrying the power splitter which is necessary to properly connect the 
present embodiment of the roll-out antenna system. 
The roll-out antenna system is also provided with two end-cap assemblies, 
designated 12a-12b in FIG. 1. Each of the end-cap assemblies 12a and 12b 
are identical, therefore the subsequent description applies equally well 
to either end-cap assembly 12a or 12b. FIG. 2 is a front elevational view 
of end-cap assembly 12a. The end-cap assembly is generally provided with 
an end plate 50, and a hub 52. The hub 52 in the presently preferred 
embodiment is of polygonal shape. The end plate 50 is fabricated of 
aluminum in the presently preferred embodiment but could be of any 
material with sufficient strength. It will also be appreciated that the 
same function of end plate 50 could be performed by a variety of 
structures, such as arm-like structures extending radially from hub 52. 
End plate 50 in the presently preferred embodiment is of approximately 
equal diameter as the reels 100 of antenna element assemblies 14a-14d. 
Upon one side of end plate 50 is mounted the hub 52. The hub is held in 
place by screws 18 which are shown best in FIG. 1 on end-cap assembly 12b. 
The polygonal shape of the hub 52 as used in the presently preferred 
embodiment can be seen best in FIG. 2. FIG. 2a provides a side-elevated 
view of the hub 52. The internal cavity of the hub 52 is enclosed by a hub 
cover 59 as shown in FIG. 2a. The hub cover 59 is secured onto the hub 52 
by screws 58, which are shown in FIG. 2. In the presently preferred 
embodiment two pair of spring-loaded antenna element connectors, 56a-56i 
b, and 56c-56d, are mounted on the surface of hub 52. Also, a female "N" 
type coaxial connector 54 is mounted on thye surface of the hub 52. Hub 52 
is constructed of a nonconducting material such as nylon so as to reduce 
capacitive coupling between antenna connectors 56a-56d. Each pair of 
antenna connectors, 56a-56b and 56c-56d, are provided so as to allow more 
efficient antenna operation in particular bandwidths. 
N-type connector 54 is to be attached to one connecting cable 162 or 163 
found on connecting cable reel assembly 16. Thus, the hub connector 54 is 
connected to the remote transmitter/receiver by way of a connecting cable 
162 or 163, the power splitter 160, and the transmission line connector 
158. Hub connector 54 is also connected to a balun 78, which is shown best 
in the cutaway portions of FIGS. 2 and 2b. Balun 78, which provides a 
transformation from an unbalanced signal to a balanced signal, is 
configured so as to be tapped at two different transformation ratios. 
Antenna connector pair 56a and 56c are connected to balun 78 at the points 
on balun 78 which provide a first transformation ratio. Antenna connector 
pair 56b and 56d are connected to balun 78 at a point which provides a 
second transformation ratio. Thus, antenna connectors 56a-56d are 
connected to a remote transmitter receiver when the antenna system is 
deployed by way of balun 78, hub connector 54, and the signal path 
described above. Multiple antenna connectors, providing different 
transformation ratios by way of balun 78 are provided because it has been 
found that the roll-out antenna system of the present invention provides 
more efficient operation at particular frequencies when particular 
transformation ratios are provided by balun 78. Therefore, it will be 
appreciated that particular applications in which the present invention 
may be used may require the alteration of the components or structure 
shown in the presently preferred embodiment but yet still come within the 
scope of the invention as claimed. The internal cavity of hub 52 is 
provided with a resilient filler material 77 to hold balun 78 in the 
proper position and also another resilient filler material 76 to protect 
balun 78 and wiring connections within hub 52 from damage. 
Each of the four antenna-element connectors 56a-56d of the presently 
preferred embodiment are of identical construction. The structure of the 
antenna element connectors 56a-56d can be seen best in the cross-sectional 
view of FIG. 2b. A corrosion-resistant bolt 80 is the central component of 
antenna-element connector 56b. Antenna connector bolt 80 is provided with 
a notch 81 on its shaft near the head of the bolt. A washer 82 is biased 
at the head of bolt 80 by a spring 84. The antenna-element connectors 
56a-56d are isolated from the hub 52 by an insulated washer 86 and an 
insulated bushing 88. Connections from balun 78 are made by way of wires 
which are provided with lugs 90 which are then frictionally fitted to the 
shaft of bolt 80 by way of a lock washer 92 and nut 94 engaged onto the 
connector bolt 80. A portion of the wiring from balun 78 to antenna 
connectors 56a-56d may be seen in the cutaway portion of FIG. 2. 
The notch 81 provided in bolt 80, as shown in FIG. 2B, of of the proper 
size so as to allow the loop 124 formed on the end of antenna elements 
118, as shown in FIG. 1, to be inserted into the notch 81 when washer 82 
is pushed downward beyond the notch. Once the antenna-element loop 124 is 
inserted into the notch, washer 82 is released and antenna-element loop 
124 is securely held in the notch 81 providing a good electrical 
connection. Furthermore, by the structure incorporated in the presently 
preferred embodiment, an antenna-element connector is provided that allows 
rapid attachment and removal of the antenna elements as well as providing 
a simple mechanical structure that is not difficult to fabricate or 
repair. 
The hub cover 59 is provided with a post generally designated at 60 in 
FIGS. 2, 2A and 2B. The post 60 is provided with a flat blade 62 mounted 
on the post head 64, the post head 64 being attached to the post screw 70 
as can be seen best in FIG. 2A. The post screw 70 is inserted through an 
opening in the hub cover 59. The threads of the post screw 70 are engaged 
by the threads of the nut 72. The nut 72 is centrally affixed to the 
inside surface of the hub cover 59. The portion of the post screw 70 which 
is exterior to the hub cavity is surrounded by a gasket 68. The gasket 68 
is made of a resilient rubber-like material which may be compressed and 
released without incurring any permanent deformity. A washer 66 is 
provided between the post head 64 and the gasket 68. By this structure, it 
is possible to compress gasket 68 by rotating the post blade 62. This is 
accomplished because as post blade 62 is rotated in the appropriate 
direction the distance between post washer 66 and the hub cover 59 is 
decreased, compressing the gasket 68 and causing it to expand its 
circumference in response to the increased pressure. The gasket 68 may be 
returned to its original circumference by rotation of the post blade 62 in 
the reverse direction. 
When the portable roll-out antenna of the presently preferred embodiment is 
to be stored or transported, the antenna elements are wound upon their 
respective antenna-element reels 14a-14d and connecting cables 162 and 163 
are wound upon the connecting cable reel assembly 16. With the antenna 
elements and connecting cables wound upon their respective reels, the 
presently preferred embodiment may be formed into a compact transportable 
package by stacking two of the antenna-element reel assemblies, such as 
14c-14d as shown in FIG. 1, onto the hub 52 of the end-cap assembly 12a or 
12b. The opening 114 of the antenna-element reel assembly is shaped so as 
to complement the polygonal shape of hub 52. The distance at which hub 52 
extends outwardly from end plate 50 corresponds to the width of two 
antenna-element reel assemblies such as 14a-14b or 14c-14d. By fabricating 
hub 52 so as to match the dimensions of opening 114 and the width of two 
antenna-element reels 14a-14b, the exterior surface of hub cover 59 will 
fit flush against one side of connecting cable reel assembly housing 152 
when post 60 and hub 52 are inserted through the openings 114 of either 
pair of antenna-element reel assemblies 14a-14b or 14c-14d. Post 60 is 
then received into bore 170. The post blade 62 is received into the bore 
slot 172. Once the post 60 and the post blade 62 have been properly 
received by the bore 170 and the bore slot 172, and a pair of 
antenna-element reel assemblies have been stacked on the hub 52, the 
end-cap assembly, 12a or 12b, may be locked into position by rotating end 
plate 50 so as to cause the compression of gasket 68 creating a frictional 
fit between the gasket 68 and bore 170. Thus, a compact, transportable 
package is formed in which all of the electrical and physical components 
necessary for operation of the roll-out antenna of the present invention 
are included and may be easily transported or stored. As presently 
embodied, the portable roll-out antenna weighs less than 17 pounds, is 
less than eight inches in length and 9 inches in diameter. 
When operation of the presently preferred embodiment of the present 
invention for use in transmitting and receiving radio signals is desired, 
the antenna-element reel assemblies 14a-14d and the end-cap assemblies 
12a-12b are separated from the connecting cable reel assembly 16 in a 
manner the reverse of that described for assembly as described above. The 
antennt elements 118 are then rolled out from their respective reels 
14a-14d. 
In the presently preferred embodiment it has been found that an efficient 
antenna may be formed by rolling out the antenna elements 118 and laying 
them directly onto the ground or supporting them slightly off the ground 
in the pattern shown in FIG. 5. The length of antenna element which is 
rolled out is dependent upon the frequency at which the antenna system is 
to be operated. The antenna-element loop 124 is individually attached to 
the appropriate antenna connector 56a-56d on an end-cap assembly hub 52 
according to the desired operating frequency range of the antenna system. 
Each hub connector (see FIG. 2) is then connected to one connecting cable 
162 or 163. Having connected the connecting cables 162 and 163 to the hub 
connectors of end-cap assemblies 12a and 12b, the antenna elements 118 are 
able to receive a signal from, or pass a signal to, power splitter 160. 
The number of antenna elements 118 selected for use can vary. A single 
element can be hooked up and used, or a plurality of elements 118 can be 
connected together as described above, depending on the operational 
characteristics of the system that is designed. A transmission line 228 
connects power-splitter 160 of reel assembly 16 to a remote 
transmitter/receiver represented by the block designated 200. By this 
structure and configuration the portable roll-out antenna of the present 
invention may be used as an efficient radio antenna system. 
It will be appreciated that the apparatus and method of the present 
invention is capable of being incorporated in a variety of embodiment, 
only one of which has been illustrated and described above. The invention 
may be embodied in other specific forms without departing from its spirit 
or essential characteristics. The described embodiments are to be 
considered in all respects only as illustrative and not restrictive and 
the scope of the invention is, therefore, indicated by the appended claims 
rather than by the foregoing description. All changes which come within 
the meaning and range of equivalency of the claims are to be embraced 
within their scope.