11Antenna SystemsMobile antenna Systems are comprised of a radiator and a matching network.Mobile antennas have a low impedance, therefore, a matching network is required.
12Antenna Systems Systems can be mono-band or multi-band. Multi band systems can be tuned from inside the vehicle while in motion or from outside the vehicle when stopped.
13Antenna Systems: Good, Bad and Ugly All systems have some sort of loading.Center loading is best.Base loading is least effectiveBecause of their skinny coils, helically wound antennas are a compromise of the other two designs.
14SWR A good SWR is not an indicator of an effective antenna system. Click your heels and say this three times.Think of a dummy load; it has a good SWR but is not an effective antenna.
15BIG NOTE **An entire program can be had just on the discussion of antennas. All mobile antennas are a compromise of some sort and much consideration should be given to safety and the type of operating that is being done, as well as spouse appeal.End of Big Note.
16Multi Band AntennasMotorizedAutomatically tunedManually tuned
17Center Loaded Antennas Whether motorized or manually tuned, these are by far the most effective type of mobile antenna.
18Motorized AntennasCommonly called “screwdriver” antennas because the first designs used cordless screwdriver to drive the screw that adjust the coil.Uses a motor to move a large coil up and down to obtain resonance.System consist of the large coil, whip radiator, shunt coil at feed point and a control unit
19Motorized Antennas Advantages Multi band.Can be tuned from inside the vehicle.Hi “Q” Very effective antenna.Computerized control units can be added for quick band changes.
20Motorized Antennas Disadvantages Large and heavy; requires strong mounting and support brackets.Hi “Q” make tuning on low bands very touchy.
23The Yaesu ATAS-100 Active Tuning Antenna System provides HF/VHF/UHF coverage with automatic motorized tuning. Utilizing control signals from the transceivers microprocessor received via the coaxial cable, the ATAS-100's internal motor adjusts the radiator length for best SWR.
24Manually Tuned Center Loaded Multi Band Antennas Some types use taps to tap the coil at a resonant point.Other designs use multiple resonators or change resonators on a single mast.
25Bug Catchers Advantages Very effective center loaded antennas.Large coils results in Hi “Q”.Can be tapped to use on multiple bands
26Bug Catchers Disadvantages Large and heavy requires strong mounting and support.Band changes have to done while parked.
27Large coil and center loading make the Bugcatcher an excellent performer. This unit is shown with a capacitance hat.
28Capacitance HatsLoss resistance is lowered by removing turns in an inductor coil.This is then compensated for by adding capacitance above the coil.The more capacitance that is added the less inductance is needed for a given frequency.
29CPU Controlled Automatically Tuned Multi Band Antennas Uses a CPU controlled matching network and a whip antenna.Can match almost any frequency.Some models are capable of matching over a million LC combinations in less than a second.
30CPU Controlled Automatically Tuned Multi Band Antennas System can be made low profile.Internal memories save settings an allow quick band changes.
31CPU Controlled Automatically Tuned Multi Band Antennas When used with a loaded whip designed for the tuner these systems can be extremely effective.When used with a 8 ft. whip the system is less effective than loaded whip or center loaded systems.
32Interior view of YAESU FC-40 CPU controlled remote tuner for FT-897 & FT-857 radios
33ICOM AH-4 CPU controlled auto-tuner for use with many ICOM radios
34ALINCO EDX-2 for USE exclusively with ALINCO DX-70T, DX-70TH, DX-77EQ, DX--77T, DX-701 and DX-707
35SGC makes an entire line of reliable CPU controlled auto-tuners that will match almost any radiator with any radio.
36SGC’s QMS system is rugged, mounts on any vehicle and includes the CPU tuner and loaded whip antenna.
37Mono-Band Antennas Operate on a single band. Can be effective. Can be made low profile.Can be easily mounted.Inexpensive way to enter into HF mobile.
38Good results can be had with mono band antennas Good results can be had with mono band antennas. These “sticks” can be easily mounted and are lower profile.
39Antenna MountingWhich ever antenna is used the mount has to be solid, strong and safe.No sharp edges or protrusions that could cause injury.Anything flying off a moving vehicle can be deadly. Safety first.Obey DOT laws.
46GroundingA good solid ground connection to the vehicle frame is necessary for good antenna performance.Make ground connections as short as possible and to bare metal.Ground connections can be weatherproofed with undercoating spray.
47BondingBonding is connecting together loose or moving metal parts of the vehicle with grounding braid.These areas are doors, trunk and hood lids, mufflers and exhaust parts, and any other areas where metal parts may rub.Rubbing metal parts can cause excessive noise in the receiver.
48Power Power should be taken directly from the vehicle’s battery. Both positive and negative leads should be fused at the battery. If there is a fault anywhere after the fuse the fuse will do it’s job and break the circuit.
49Both leads should be fused at the battery to prevent fire.
50Power Drawing power directly from the battery helps eliminate noise. All leads should be 10 ga. or larger stranded wire and be kept as short as necessary.Protect wires with rubber grommets where they pass through the firewall or any metal.
51PowerFlexible conduit and wire ties make the job neat and also protect wires form accidentally being cut or shorted.If using an auxiliary battery, make sure that it is securely mounted with proper electrical connections and change over charging circuits.
52Grommets and conduit protects wires. Cable ties keeps things neat.
53Flexible conduit and wire ties keeps all wires dressed and neat.
54Wires and cablesKeep all wires and cables as concealed as possible.Not only does it make the job look neat but, it also protects them from damage and prevents anyone from tripping as they enter or exit the vehicle.
55Mounting The RadioThe radio should be mounted in such a way that it does not interfere with the driver’s ability to safely operate the vehicle.Period.
56Mounting The Radio Say it again. The radio should be mounted in such a way that it does not interfere with the driver’s ability to safely operate the vehicle.Period.
57Mounting The Radio The mount should… Be secure. Not obstruct the driver in any wayKeep the unit within easy reach and view.Allow proper air flow and not be in a heat source such as heat ducts.
58Mounting The RadioUnsecured objects in a vehicle are potential hazards in an accident.They can be thrown about, hitting the occupants with deadly results.
59Mounting The RadioA lot of the mobile HF radios today offer a detachable remote control head that allows to “face” of the radio to be mounted in a safe and convenient location while the main unit is mounted out of the way under a seat or in a trunk.
64Control head of this YAESU FT-100 is mounted safely and securely and allows the driver to view it at a glance.
65YAESU FT-857 control head mounted on gooseneck and radio mounted under passenger seat. A neat and secure installation.
66NoiseGrounding and shielding should eliminate most noise in your receiver and on your transmitted signal.Ferrite on speaker leads and other leads to electronics and CPU modules can remedy RFI in the vehicle.
67NoisePreviously mention bonding of metals parts can prevent unwanted receiver static noise.A large capacitor from the positive lead to ground will eliminate AC noise on DC power cables.
68NoiseRFI to your vehicle can be a problem. Some fuel pumps or other devices have been known to shut down in the presence of strong RF signals.Consult your vehicle manufacturer for any Technical Service Bulletins (TSB) regarding these issues.