|"No-Ground Plane" Firestik CB
PURPOSE: The FG-648 series, "No ground plane" (NGP) CB antenna kits were specifically designed to solve the problems associated with the lack of ground plane (counterpoise). This normally occurs on vehicles constructed of plastic, fiberglass, wood or aluminum. This includes, but is not limited to, motor homes, boats, automobiles and 18-wheeler trucks. Ground plane problems typically show up in the form of high standing wave ratio (SWR) and poor performance. The isolated ground plane that is built into the FG-648 series kits can also eliminate problems on metal base vehicles that lack the sufficient ground plane for proper operation. This could be due to the size of available ground plane (ATV, bicycle, motorcycle, wheelchair, etc.), or because the operator chooses to mount the antenna in a location that is unable too properly take advantage of available ground plane. The versatility of these kits goes way beyond the normal expected uses of a typical mobile antenna kit. Aside from vehicular installations, these kits can be mounted on a pack frame for hunting or Search and Rescue operations. Apartment dwellers can mount them on a balcony railing, or a temporary base station can set up in the forest using a tree for a tower.
ANTENNA: The antennas used in these kits utilize the same 5/8 wave design as the patented Firestik II tunable tip antennas. The antenna's frequency is altered in order to maintain a desirable center band position when used with the tuned coaxial feed line. Accordingly, these antennas may only be used with the Firestik NGP cable. The core material is a 3/8-inch (0.375" or 10mm) diameter reinforced plastic (fiberglass). Our custom blended formula offers a preferred balance of flexibility and strength. The chrome plated machine brass mounting base has standard 3/8"-24 threads. A high efficiency, voltage increasing helical wind is utilized. Heavy insulated copper wire is used to guard against shorted coils and corrosion induced resistance commonly found on non-Firestik brand antennas. The antenna used in these kits have our patented "no tools required" tunable tip for fast and easy SWR adjustments. The rated wattage for these kits is 100 watts. Each antenna is covered with a static reducing, heavy PVC shrink tubing with both pigment and UV stabilizers mixed in. Available in black.
COAXIAL FEEDLINE: The seventeen-foot (5.2 M) coaxial cable used in these kits is of the highest quality. As a matter of fact ... our NGP cable assembly utilizes a custom manufactured coaxial cable that can only be found at Firestik. Unable to find the performance characteristics in any of the commercially available coaxial cable ... we designed our own. First we use a multi-wire stranded center conductor to the prevent breakage that can occur with solid center conductor cable. A condition known as "cold working" occurs where vibration is present and this action can cause solid conductors to become brittle and eventually break. Surrounding the center conductor is a long life, flexible, polyethylene insulation. Since shielding is extremely critical on NGP systems, we used a double shield around the center conductor. First, a 100% aluminum tape covers the center conductor insulator and then a copper wire braid (averages 95% coverage versus the industry standard of 70%) is applied over the aluminum tape. The coaxial feed line, besides being the conduit for the signal to reach the antenna, serves as a tuned circuit that creates the necessary counterpoise. If a longer cable length is required, the user may add standard RG-58 A/U cable between the radio and system cable, preferably in lengths that are multiples of nine feet. Because it is a tuned circuit, the length cannot be reduced without causing non-repairable damage. Should the cable become damaged, order replacement cable model K-8NGP.
MOUNT, SPRING AND HARDWARE: To compliment the quality of the antenna and feed line, the mount used in these kits is our stainless steel, 3-way 90° angle mount. Mounting options are, 1) any vertical bar, rail or post, or 2) any horizontal bar, rail or post, and 3) any flat vertical surface such as the side of the vehicle. For a closer view of the mount, click on the following model number SS-64. A stainless steel spring with machined brass ends acts as the coupling between the antenna and the feedline.