Abstract:
A combined antenna system used for both vehicles and structures, whereby a satellite antenna is placed concentrically around a conventional mast antenna that can be used for both conventional FM radio and also terrestrial retransmission of the satellite broadcast signals. The combined antenna system, in a vehicle implementation, is configured to use only the one hole created in the vehicle manufacturing process, thereby preventing the necessity of drilling a second hole for the satellite antenna, which alleviates deterioration of the vehicle&#39;s body. Additionally, because the combined antenna system can be advantageously placed, a shorter RF cable connecting it to a receiver box can be implemented than otherwise would be the case for a satellite antenna located on a window or roof of a vehicle. In an alternative embodiment, the satellite antenna can be mounted on either a fixed or retractable terrestrial antenna, thereby raising the satellite antenna to a higher elevation with respect to any obstacles on the vehicle or structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Related subject matter is disclosed in U.S. Pat. No. 6,259,033, issued Sep. 25, 2001; in co-pending U.S. non-provisional patent application Ser. No. 09/953,146, filed Oct. 19, 2000; in co-pending U.S. non-provisional patent application Ser. No. 09/982,112, filed Oct. 19, 2001; and in co-pending U.S. non-provisional application Ser. No. 09/844,699 filed Apr. 30, 2001, the entire content of each said patent and application being expressly incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates generally to radio antennas. More particularly, the invention relates to terrestrial radio and satellite communication antennas for vehicles and other mobile or fixed structures. The invention also relates to an integral antenna assembly that comprises one or more antennas for mounting externally on the surface of a vehicle or other mobile or fixed structure.  
         BACKGROUND OF THE INVENTION  
         [0003]    With reference to FIGS. 1 and 2, a number of antenna systems have been proposed which provide for the reception of satellite transmission signals on vehicles and other mobile or fixed structures. FIG. 1 illustrates a known antenna system that allows transfer of RF energy across a dielectric such as glass for reception of satellite transmitted signals. The antenna illustrated in FIG. 1 provides for the transfer of radio frequency (RF) energy through glass or other dielectric surface to avoid having to drill holes, for example, through the windshield or window of an automobile for installation. After-market glass-mount antenna systems are advantageous because they obviate the necessity of having to provide a proper seal around an installation hole or other window opening in order to protect the interior of the vehicle and its occupants from exposure to external weather conditions.  
           [0004]    In the known antenna system  20  depicted in FIG. 1, RF signals from an antenna  22  are conducted across a glass surface  24  via a coupling device  26  that typically employs capacitive coupling, slot coupling or aperture coupling. The portion of the coupling device  26  on the interior of the vehicle is connected to a matching circuit  28  which provides the RF signals to a low noise amplifier (LNA)  32  at the input of a receiver  34  via an RF or coaxial cable  30 .  
           [0005]    [0005]FIG. 2 illustrates an alternative embodiment of the antenna system of FIG. 1, except that antenna  42  has been displaced to the roof of the vehicle, and is kept in place by a magnet or other securing means. Through cable  54  the RF signal travels to coupler  45 , through the vehicle&#39;s glass (e.g., back windshield) and to second coupler  44 . The RF signal then travels through RF cable  46 A to LNA  47  and then through RF cable  46 B to receiver  48 .  
           [0006]    Both types of antenna mounting systems —the window mount system and roof mount magnetic system of FIGS. 1 and 2 respectively —suffer from serious deficiencies. First, the antenna of either FIG. 1 or FIG. 2 is, in all likelihood, a second or even third antenna, and thus adds an unsightly appearance to the vehicle or structure. Regarding the window mount system of FIG. 1, RF coupling loss through glass is generally 1dB or higher. This causes an increase in noise figure that results in degradation of receiver sensitivity.  
           [0007]    Regarding the body mount system of FIG. 2, there are also serious deficiencies. For example, the installation of antenna  42  is located remotely with respect to LNA  47  and radio receiver  48  is generally considered unattractive to consumers of mobile satellite services. This is true for several reasons. First, an antenna mounted on the roof of a vehicle adds to the clearance height of the vehicle, which may be prove to be troublesome if parking in a garage. Often, users will forget that the antenna is on the roof, and will cause damage either to the antenna itself and/or the vehicle. Or, the user may have to stop the vehicle, exit it, and dismantle the antenna in order to proceed to park in the garage. This is, of course, a needless waste of time and energy.  
           [0008]    Secondly, the roof mounted antenna is unsightly, not only to the external observer, but also to the occupants in installations where the RF cables must be routed through the interior of the vehicle. In the case of a window mounted antenna, the couplers may obstruct vision and generally make the appearance of the vehicle unsightly.  
           [0009]    A need therefore exists for a vehicle antenna mounting system whereby both types of antenna (i.e., a vehicle&#39;s OEM supplied AM/FM antenna and an antenna for the reception of SDARS signals) can be co-located, so as to minimize, if not entirely prevent, any additional holes in a vehicle&#39;s exterior shell or eliminate the need to locate a magnetically mounted antenna on the glass of an auto, or to use antenna couplers in the glass portion of an auto, yet provide an integral assembly for installation on the exterior of a vehicle, and an effective means for reception of both terrestrial AM/FM signals and satellite transmitted signals.  
         SUMMARY OF THE INVENTION  
         [0010]    The above described disadvantages are overcome and a number of advantages are realized by the present invention which relates to a combined satellite and terrestrial antenna system for a structure. The combined satellite and antenna system comprises a terrestrial antenna mounted on a mounting assembly, and a satellite antenna concentrically mounted with respect to the terrestrial antenna, with the mounting assembly comprising a low noise amplifier circuit and a bezel, the bezel adapted to contain the low noise amplifier.  
           [0011]    The present invention further relates to a combined satellite and terrestrial antenna system for a vehicle, which comprises a terrestrial antenna mounted on a mounting assembly, and a satellite antenna concentrically mounted with respect to the terrestrial antenna, with the mounting assembly comprising a low noise amplifier circuit and a bezel. The bezel is adapted to contain the low noise amplifier, and the mounting assembly is mounted on the vehicle.  
           [0012]    Additionally, the present invention relates to a method for mounting a combined satellite and terrestrial antenna system on a structure comprising the steps of mounting a terrestrial antenna on a mounting assembly; mounting the satellite antenna concentrically with the terrestrial antenna; mounting the mounting assembly in a mounting hole on a structure, wherein the mounting assembly comprises a low noise amplifier circuit and a bezel, with the bezel adapted to contain the low noise amplifier; locating satellite receiver hardware in proximity to the combined satellite and terrestrial antenna system; and connecting the satellite antenna, the terrestrial antenna, the satellite receiver hardware and terrestrial receiver hardware with appropriate cables. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The novel features and advantages of the present invention will best be understood by reference to the detailed description of the specific embodiments which follows, when read in conjunction with the accompanying drawings, in which:  
         [0014]    [0014]FIG. 1 illustrates a known antenna system that allows inductive transfer of RF energy across a dielectric such as glass for reception of satellite transmitted signals;  
         [0015]    [0015]FIG. 2 illustrates an alternative known embodiment of the antenna system of FIG. 1 mounted on a vehicle;  
         [0016]    [0016]FIG. 3 illustrates a combined multi-band terrestrial and satellite antenna system installed on a vehicle for reception of AM, FM, satellite and terrestrial re-transmitted satellite signals according to an embodiment of the present invention;  
         [0017]    [0017]FIG. 4 illustrates a quadrifilar antenna etched on a flexible substrate that may be used in a combined multi-band terrestrial/satellite antenna according to an embodiment of the invention;  
         [0018]    [0018]FIGS. 5A and 5B illustrate the mechanical configurations of a combined multi-band terrestrial/satellite antenna according to an embodiment of the present invention;  
         [0019]    [0019]FIG. 6 illustrates the installation of a combined multi-band terrestrial/satellite antenna in a vehicle according to an embodiment of the invention;  
         [0020]    [0020]FIGS. 7A and 7B are schematic block diagrams of a multi-band terrestrial antenna, satellite antenna, low-noise amplifier and cabling at the point of installation according to alternative embodiments of the invention;  
         [0021]    [0021]FIG. 8 is a schematic block diagram of a combined multi-band terrestrial and satellite antenna system for reception of AM, FM, satellite and terrestrial re-transmitted satellite signals according to another embodiment of the invention; and  
         [0022]    FIGS.  9 A- 9 C illustrate an alternative embodiment of a combined multi-band terrestrial/satellite antenna according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    The various features of the preferred embodiment will now be described with reference to the drawings, in which like parts are identified with the same reference characters.  
         [0024]    [0024]FIG. 3 illustrates a combined multi-band terrestrial and satellite antenna system installed on a vehicle for reception of AM, FM, satellite and terrestrial re-transmitted satellite signals according to an embodiment of the present invention. The combined multi-band terrestrial/satellite antenna system  300  illustrated in FIG. 3 comprises a combined multi-band terrestrial/satellite antenna  350  which is, itself, comprised of multi-band terrestrial antenna  302 , satellite antenna  304 , bezel  306 , nut  308 , bolt  310 , low noise amplifier (LNA) housing  326 , SDARS satellite (SDARS/SAT) cable  312 , SDARS terrestrial (SDARS/TER) cable  316  and AM/FM cable  322 . The system further comprises SDARS receiver (SDARS/RX)  314 , SDARS audio cable  330 , and combined head unit and AM/FM tuner  328 . Combined head unit and AM/FM tuner  328  is comprised of AM/FM tuner  324 , and head unit  320 . Multi-band terrestrial antenna  302  is used to receive conventional AM and FM transmitted signals and terrestrial retransmission of satellite transmitted signals. In other embodiments, it may receive and transmit cellular telephone signals, for example. Satellite antenna  304  may receive satellite transmitted signals directly. Combined multi-band terrestrial/satellite antenna  350  is shown mounted on surface  318 , which might be the surface (or fender) of an automobile or other vehicle, or the surface of many other fixed or mobile structures.  
         [0025]    As can be seen in FIG. 3, multi-band terrestrial antenna  302  has coaxially mounted around it satellite antenna  304 . Both are secured through the mounting hole provided in surface  318 , via nut  308  and bolt  310 . The two antennas are mounted on bezel  306 , which allows the antenna to always be vertical, even if surface  318  is somewhat slanted. Bezel  306  is mounted on surface  318 . SDARS/SAT cable  312 , SDARS/TER cable  316  and AM/FM cable  322  pass through bolt  310 , which has a suitably large hollowed-out portion to pass the three cables through. In FIG. 8, a second embodiment of the invention is shown, and SDARS/TER cable  316  and AM/FM cable  322  are combined into AM/FM/SDARS/TER cable  718 ; this cable is also discussed in reference to FIG. 7. LNA housing  326  may, according to an embodiment of the invention, reside within bezel  306 . Other configurations of LNA housing  326  are possible. Bezel  306 , LNA housing  326  (and its components), nut  308  and bolt  310  comprise mounting assembly  350 . LNA housing  326  will be discussed in detail in reference to FIGS. 7 and 8 below.  
         [0026]    If surface  318  is the surface of an automobile, combined terrestrial/satellite antenna system  300  will have been located on a manufacturer-provided hole, i.e., one that the automobile manufacturer provided for the purpose of installing an AM/FM mast antenna. As such, no additional holes are needed, which eliminates the danger of corrupting the protective paint and/or rust-inhibiting materials applied by the manufacturer.  
         [0027]    The two antennas, multi-band terrestrial antenna  302  and satellite antenna  304 , can occupy only one space and utilize only one hole in a vehicle or structure&#39;s body, yet can provide access to at least two different services, as will be described in detail below. With regard to the discussion and the figures, the use of the combined multi-band terrestrial/satellite antenna  300  will be as if it were placed on an automobile; however, as will be discussed in detail below, combined multi-band terrestrial/satellite antenna  300  may be used with various vehicles and structures.  
         [0028]    Multi-band terrestrial antenna  302  is used for AM and FM radio reception and for reception of terrestrial retransmission of the satellite transmitted signal. AM and FM radio is generally used for audio reception only, that is, for transmissions from local radio stations with various programming formats, including music, news, sports, “talk radio”, and so on. These programming formats are familiar to many people and are the kind that are commonly received by users in their vehicles and mobile or fixed structures today. However, multi-band terrestrial antenna  302  may also be used for two-way cellular telephony and for reception of terrestrial retransmission of a satellite transmitted &#39;signal. The latter application will be discussed below.  
         [0029]    The second antenna, satellite antenna  304 , receives satellite transmission signals directly from one or more satellites placed in synchronous or non-synchronous earth orbits. Satellite transmissions may be used for audio programming, but can be used for other purposes as well.  
         [0030]    As mentioned above, multi-band terrestrial antenna  302  is preferably used for AM and FM radio reception, and for reception of terrestrial retransmission of satellite transmitted signals. Radio frequency transmissions are often subject to multipath fading. This is especially true of satellite transmitted signals. Signal blockages at receivers can occur due to physical obstructions between a transmitter and the receiver or service outages. For example, mobile receivers encounter physical obstructions when they pass through tunnels or travel near buildings or trees that impede line of sight (LOS) signal reception. Service outages can occur when noise or multipath signal reflections are sufficiently high with respect to the desired signal. At these times, when a direct line-of-sight transmission path between the satellite and satellite antenna  304  is blocked, retransmission of the satellite signals from terrestrial retransmitters is very useful.  
         [0031]    Referring again to FIG. 3, it can be seen that satellite antenna  304  is placed concentrically around multi-band terrestrial antenna  302  (this can also be seen in greater detail in FIGS. 5A and 5B). Satellite antenna  304  is preferably a quadrifilar helix antenna. A satellite antenna  304  that is comprised of a quadrifilar helix antenna has good performance in receiving satellite transmissions from geosynchronous orbit satellites. Since satellite antenna  304  is placed concentrically around multi-band terrestrial antenna  302  installation of satellite antenna  304  can be an after-market addition or by the original equipment manufacturer or OEM (automobile manufacturer). In both cases, the RF cables coming from both antennas will fit into the existing pre-cut hole that existing multi-band terrestrial antenna  302  has already been mounted on.  
         [0032]    Mounting satellite antenna  304  around multi-band terrestrial antenna  302 , which is itself mounted in an OEM-supplied hole, prevents the necessity of cutting an additional hole in a vehicle or structure thereby avoiding destroying the exterior finish and/or appearance of the vehicle or structure. It also eliminates the need to use a magnet (for a roof mounted system) or through-the-glass couplers (for window mounted systems). It is well known in the automotive industry that the application of paints and finishes provides a decorative and appealing uniform appearance, and prevents or inhibits the formation of rust in or on the body of the vehicle. By cutting a hole through this finish or paint, the intent of the manufacturer is circumvented in that a means for deterioration of the automotive body is provided. That is, it will be more likely than not that rust would form and water could enter and damage the interior of the vehicle. Additionally, drilling a hole in the surface of a fender of a vehicle adds the risk of chipping the paint and/or finish material, which may detract form the appearance of the vehicle. Also, placing a second antenna may be considered to be unattractive by many people.  
         [0033]    Referring again to FIG. 3, combined multi-band terrestrial/satellite antenna  300  has three cables that lead from its base to other components of the system. The first cable is SDARS/SAT cable  312 , which will be discussed in detail with reference to FIGS. 7 and 8. SDARS/SAT cable  312  carries the amplified received satellite signal. The second cable is SDARS/TER cable  316 , which is also discussed in reference to FIGS.  7  and  8 . SDARS/TER cable  316  carries the amplified terrestrial retransmission of a satellite (or cellular) signal. The third cable is AM/FM cable  322  which carries the AM/FM terrestrial signals received by multi-band antenna  302 . However, because the two antennas are co-located, for example, on the trunk or rear fender of a vehicle, other components of combined multi-band terrestrial/satellite antenna system  300  may be located, for example, in the trunk of the vehicle, SDARS/SAT cable  312  and SDARS/TER cable  316  maybe shorter than otherwise would be the case (especially if satellite antenna  304  were roof or window mounted). A shorter length SDARS/SAT cable  312  and SDARS/TER cable  316  will significantly cut down on cable loss and thereby improve the capability (i.e., increase the signal-to-noise ratio and hence the sensitivity) of the radio. Another advantage is the cost savings due to a shorter cable.  
         [0034]    [0034]FIG. 4 illustrates a quadrifilar antenna etched on a flexible substrate that may be used in a combined multi-band terrestrial/satellite antenna according to an embodiment of the invention. Satellite antenna  304  is comprised of quadrifilar helix antenna, among other items, which will be discussed in detail in reference to FIGS. 5A and 5B. Conductive quadrifilar antenna elements  402  are etched on a flexible insulating substrate  403 , according to a design which is well known to those skilled in the art. A weatherproofing material (not shown) may be applied to the exterior surface, in order to protect quadrifilar antenna  402  from the deteriorating effects of rain, sunshine, etc. Additionally, a binding agent (not shown) may be applied to the interior surface of quadrifilar antenna  304  when fabricated into the final form as shown in FIGS. 5A and 5B.  
         [0035]    [0035]FIGS. 5A and 5B illustrate the mechanical configurations of a combined multi-band terrestrial/satellite antenna according to an embodiment of the present invention. FIG. 5A is an elevational view of combined multi-band terrestrial/satellite antenna  300 . Satellite antenna  304  has within it a terrestrial antenna bore  504 , to receive multi-band terrestrial antenna  302 . LNA housing  326  is located at the base of combined multi-band terrestrial/satellite antenna  300 . In one embodiment, LNA housing  326  is designed to be concealed within bezel  306 . In different embodiments LNA housing might be located several feet away from combined multi-band terrestrial/satellite antenna  300 . LNA housing  326  will be further discussed in reference to FIGS. 7 and 8.  
         [0036]    [0036]FIG. 5B is a top view of combined multi-band terrestrial/satellite antenna  350 . Here, it can be seen that terrestrial antenna bore  504  which is located at or near the center of satellite antenna  304 , is large enough to slide over terrestrial antenna  302 , and with the application of mounting glue or epoxy, will stay firmly in contact with the multi-band terrestrial antenna  302 . Quadrifilar antenna  304  is placed around spacer  506 , within which is formed terrestrial antenna bore  504 .  
         [0037]    [0037]FIG. 6 illustrates the installation of a combined multi-band terrestrial/satellite antenna on a vehicle according to an embodiment of the invention. FIG. 6 shows two heights, first height (h) which is the height of satellite antenna  304  and second height (H) which is the height of the roof of vehicle  602 . Additionally, there is shown angle Φ. Angle Φ is the angle formed by a vertical line derived from first H and second h and a horizontal line comprised of length l. Length l is the distance between a vertical line established by combined multi-band terrestrial/satellite antenna  300  and apex of the roof closest to where combined multi-band terrestrial/satellite antenna  300  is located. Angle Φ should be less than 20°, in order to provide satisfactory reception from a geosynchronous orbit satellite at northerly latitudes. Angle Φ is equal to tan −1 ((H+h)/(l)).  
         [0038]    Three factors affect angle Φ. The first is that for a given length l and second H, making first h greater would reduce angle Φ. Conversely, reducing first h would increase angle Φ (it is well known that most vehicles satisfy the condition Φ&lt;20 degrees). The second factor is that for a given second H and first h, making length l longer, would reduce angle Φ. Conversely, reducing length l would increase angle Φ. And lastly, for a given length l and first h, making second H shorter, would reduce angle Φ. Conversely, increasing second H would increase angle Φ.  
         [0039]    Therefore, it can be seen that in some circumstances angle Φ would be too great if configured as shown. In these circumstances a spacer may be placed under satellite antenna  304  to raise it up making first h greater thereby reducing angle Φ. These relationships are shown below:  
                     Angle                 Φ     =       tan     -   1            (       H   -   h     l     )                       Tan                 20     =   0.363                                    ∴         H   -   h     l     ≤   0.363                                              
 
         [0040]    [0040]FIG. 7A is a schematic block diagram of a multi-band terrestrial antenna, satellite antenna, low-noise amplifier and cabling at the point of installation according to an embodiment of the invention. FIG. 7A shows the necessary electrical components to make combined multi-band terrestrial/satellite antenna  350  perform properly. Each antenna has a single RF cable originating from it. In the case of satellite antenna  304 , it is satellite antenna output cable  702 , and in the case of multi-band terrestrial antenna  302 , it is multi-band terrestrial antenna output cable  706 . Both of these cables are input to LNA housing  326 .  
         [0041]    In LNA housing  326 , satellite antenna output cable  702  is connected directly to satellite low-noise amplifier (SAT/LNA)  704 , and multi-band terrestrial antenna output cable  706  is connected to both terrestrial low noise amplifier (TER/LNA)  710  and inductor  708 . Multi-band terrestrial antenna output cable  706  is connected to AM/FM cable  322  through inductor  708 . The purpose of inductor  708  is to act as an open circuit (or high impedance) at the satellite terrestrial retransmission frequency, and as a short circuit (low impedance) at normal AM and FM radio transmission signal frequencies. This configuration does not cause any degradation on either antenna system (i.e., terrestrial antenna  302  or satellite antenna  304 ). Inductor  708  and TER/LNA  710  are contained in SDARS/AM/FM combiner  716 , which is itself contained in LNA housing  502 . Both satellite antenna output cable  702 , and multi-band terrestrial antenna output cable  706  are very short, so the low noise figures of SAT/LNA  704  and TER/LNA  710  are maintained.  
         [0042]    Inductor  708  may be replaced by a circuit  750  which can be configured to operate in the same manner as inductor  708 . This can be seen in FIG. 7B which is identical to FIG. 7A except for the replacement of circuit  750  for inductor  708 . That is, the circuit  750  could be comprised of a plurality of passive devices, active devices, or a combination of passive and active devices to act as an open circuit (or high impedance) at the satellite terrestrial retransmission frequency, and as a short circuit (low impedance) at normal AM and FM radio transmission signal frequencies. This configuration does not cause any degradation on either antenna system (i.e., terrestrial antenna  302  or satellite antenna  304 ). The circuit  750  and TER/LNA  710  would be contained in SDARS/AM/FM combiner  716  (as inductor  708  discussed above), which is itself contained in LNA housing  502 . No design configurations of circuit  750  need be shown, because, as one skilled in the art would recognize, innumerable configurations are possible which would adequately perform the aforementioned functions of acting as a high impedance at certain frequencies and a low impedance at other frequencies.  
         [0043]    The output of SAT/LNA  704  is connected to SDARS/SAT cable  312 . Referring back to FIG. 3, SDARS/SAT cable  312  is connected directly to SDARS/RX  314 , and carries the amplified signal received by satellite antenna  304 . The output of TER/LNA  710  is connected to SDARS/TER cable  316 . This cable carries the amplified signal received by multi-band terrestrial antenna  302 . The signals received by multi-band terrestrial antenna  302  and then amplified by TER/LNA will encompass a broad range of signals, i.e., AM, FM, terrestrial re-transmissions of satellite signals, and perhaps even cellular signals, hence the term “multi-band”. Suitable selection of TER/LNA  710  can have the effect of filtering undesirable signals (to a certain extent), or not, depending on specific design criteria.  
         [0044]    In the first embodiment of the combined multi-band terrestrial/satellite antenna system, shown and discussed in reference to FIG. 3, three cables originated from combined multi-band terrestrial/satellite antenna  350 . As discussed above, the three cables were connected to specific locations. As shown in FIG. 8, a second embodiment of the combined multi-band terrestrial/satellite antenna radio system  300  is possible, with the use of AM/FM/SDARS/TER cable  718 . AM/FM/SDARS/TER cable  718  is a cable assembly which combines AM/FM cable  322  and SDARS/TER cable  316  into one assembly, for connection to a splitter, which will be discussed in detail below with reference to FIG. 8.  
         [0045]    [0045]FIG. 8 is a schematic block diagram of a combined multi-band terrestrial and satellite antenna system for reception of AM, FM, satellite and terrestrial re-transmitted signals according to another embodiment of the invention. In most circumstances, SDARS/RX  314  and SDARS/AM/FM splitter  802  would be located in the trunk of a vehicle, or if the radio is in a mobile or fixed structure, they would be located close to combined multi-band terrestrial/satellite antenna  350 . As discussed above, the output of SAT/LNA  704  is SDARS/SAT cable  312  and the output of TER/LNA  710  is SDARS/TER cable  316 . SDARS/TER cable  316  may then be bundled with AM/FM cable  322  into AM/FM/SDARS/TER cable  718  and connected to SDARS/AM/FM splitter  802 . Both of these cables may be up to 15 feet in length.  
         [0046]    SDARS/RX  314  receives SDARS/SAT cable  312  and the first output of SDARS/AM/FM splitter  802 , SDARS cable  806 . The former is directly received satellite transmitted RF signals, and the latter is the terrestrial retransmission of the same satellite transmitted signals. The output of SDARS/AM/FM combiner  716  is AM/FM/SDARS/TER cable  718 . AM/FM/SDARS/TER cable  718 , which contains AM/FM cable  322  and SDARS/TER cable  316 , is input to SDARS/AM/FM splitter  802 . SDARS/AM/FM splitter  802  isolates the AM/FM and terrestrial re-transmitted satellite signals. The other output of SDARS/AM/FM splitter  802  is AM/FM/splitter cable  808 , which is input to AM/FM tuner  324 , the output of which is connected to head unit  320  via AM/FM tuner output cable  810 . Head unit  320  also receives an output from SDARS/RX  314 , which is the down-converted satellite transmission signal, which head unit  320  can then process and convert to an audio signal. The down-converted signal is carried by SDARS/Audio cable  330 . Likewise, the output of AM/FM tuner  324  is a down-converted signal which head unit  320  can process and output as audio, to speakers (not shown). The signals contained in SDARS audio cable  330  and AM/FM tuner output cable  810  may be either analog or digital signals. If combined head unit AM/FM tuner  328  is located in a home, office or other large structure, it would be placed in a location convenient for the use of the occupant(s) of the structure.  
         [0047]    Although discussion of the combined satellite/terrestrial antenna  350  and combined satellite/terrestrial antenna system  300  has focused on the particular application of an automobile, it should be readily apparent to one skilled in the art, that the combined satellite/terrestrial antenna system  300  can be just as easily used in an aircraft, boat, train, mobile home, recreational vehicle or truck. Each installation should ideally follow the same requirements as discussed with respect to FIG. 6, i.e., that angle Φ be less than 20°. Care should be taking when installing combined terrestrial/satellite antenna  350  so that such installation does not defeat the minimum angle criterion.  
         [0048]    FIGS.  9 A- 9 C illustrate an alternative embodiment of a combined multi-band terrestrial/satellite antenna according to the invention. In FIG. 9A satellite antenna  304  is configured to ride on the uppermost or highest portion of the terrestrial antenna  302 . In this manner, the previously described restrictions on the angle between the roof of automobile  602  and the satellite antenna  304 , for all practical purposes, disappears. In this alternative embodiment, the satellite antenna  304  is preferably located on the top, or highest vertical portion, of a fixed or retractable terrestrial antenna  302 . If the terrestrial antenna  302  is fixed, then the embodiments of FIGS. 9B and 9C (described below) do not apply. That is, the combined satellite and terrestrial antenna structure would remain in the position illustrated in FIG. 9A.- Of course, if the terrestrial antenna  302  is fixed, the satellite antenna  304  can be located at any point from the top to the bottom of the terrestrial antenna  302 , and in most of those positions, the angular restriction discussed earlier would not be applicable.  
         [0049]    Alternatively, the terrestrial antenna  302  may be a retractable antenna. In this case, it will descend into a suitable recessed area in the auto  602  such that it alone (as shown in FIG. 9C), or in combination with the satellite antenna  304  (as shown in FIG. 9B), resides completely within the recessed area. The advantage of the embodiments of FIGS.  9 A- 9 C is that the angular restriction discussed above for the satellite antenna fixed in position at the base of the terrestrial antenna  302  is no longer an issue because the satellite antenna  304  rides either even with or above the roof of the auto  602 . This improves reception capabilities of the satellite transmitted signals. Although the RF cabling connections to the satellite antenna  304  are not shown in FIGS.  9 A- 9 C, one skilled in the art can understand and recognize that the RF cables can be contained within the core of the terrestrial antenna  302 .  
         [0050]    The present invention has been described with reference to certain exemplary embodiments thereof. However, it will be readily apparent to those skilled in the art that it is possible to embody the invention in specific forms other than those of the exemplary embodiments described above. This may be done without departing from the spirit of the invention. The exemplary embodiments are merely illustrative and should not be considered restrictive in any way. The scope of the invention is defined by the appended claims and their equivalents, rather than by the preceding description.