PURPOSE: The LGX-M2 (where X = antenna length in feet) 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, motorhomes, 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 these 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. These kits utilize a stylish mount made specifically for mounting on the vertical side of a vehicle or structure. Aside from being a NGP kit, the main feature of these kits is that they utilize a lightweight antenna. The antennas are at least 40% lighter than the heavy-duty antenna used in the FGX-648 kits. This offers a more stylish look, while at the same time reducing mount stress that is caused by physical weight and wind load.
ANTENNA: The antennas used in these kits utilize the same 5/8 wave design as the patented tunable-tip FireFly antennas. The antenna's frequency is altered in order to maintain a desirable center band position when used with the tuned coaxial feedline. Accordingly, these antennas may only be used with the Firestik NGP cable. The core material is a 5/16-inch (0.313" or 8mm) diameter reinforced plastic (fiberglass) tube. 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, light-gauge 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 colors are black, red or white with a black tip.
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, polyethelene 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 feedline, 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 AND HARDWARE: These kits use our molded "teardrop" side mount. The black plastic shell has a textured finish to keep it looking nice. All hardware and coax connections are hidden in the inner wall of the vehicle to maintain visual integrity and prevent weather exposure. For additional contact protection, a spring may be added between the antenna and the mount. If you choose to add a spring, a split-lock washer should be added between the spring and the mount for proper seating.
*** IMPORTANT INSTRUCTIONS ***
WARNING! The coax cable in this kit contains an internal circuit. It can ONLY be used with Firestik no-ground-plane (NGP) antennas. NGP antennas and coax cables ARE NOT interchangable with ground plane (GP) dependent antennas or coax. Also, the length of the coax is CRITICAL. It is a tuned circuit. While there are some VERY rare instances when installation anomolies can be corrected via the coax cable, the installer SHOULD NOT alter the length of the 'No-Ground-Plane' (NGP) cable unless specifically instructed to do so by a Firestik technician. If additional length is required between the antenna and radio, use a barrel connector and RG-58A/U coax in lengths multiple of 9 feet (9, 18, 27, etc.).
The ring terminal for the antenna end of the cable was left off so that the installer can pass it through small access holes. We recommend that the ring terminal be soldered on versus crimped. If it ever becomes necessary to remove the coax for service, it will be near impossible to remove a crimped on ring terminal without losing some coax length.
Unlike conventional GP antenna systems, the NGP coax only uses the center conductor at the antenna end. Do not attempt to ground the coax shield at the antenna end. Grounding the coax at the mount end will prevent proper operation of the antenna system and may cause damage to the radio. Please note that continuity is normal when measured between the center pin and housing of the radio-end PL-259 connector. This is normal on all Firestik NGP kits.
Lastly , use care when routing the coax. Try to avoid pulling the cable through areas with sharp edges. The outer jacket is soft and could become damaged. If there is excess cable length, DO NOT coil it up, as this could cause an unfavorable reaction (RF choke). You MAY either let the excess lay loosely in a headliner or wall or, form the excess into a 12" or longer bow-tie type configuration with a wire-tie in the center.
Like all other antennas that are expected to transmit energy, the NGP antennas should have their SWR fine tuned after mounting. Setting SWR maximizes performance, highlights possible trouble and protects the radio from potential damage.