HF Mobile Installation and Operation

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HF Mobile Installation and Operation
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Why HF Mobile?

• HF Bands are used for Long and Medium haul
  communications. VHF UHF for short range or
  local communications.

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Why HF Mobile?

• With todays modern compact transceivers it is
  possible to have portable HF communication in our
  vehicles.

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Components Of A Mobile Station

• Transceiver
• Antenna System (radiator matching network)
• Power Source

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Transceivers

• There are many HF transceivers on the market
  made specifically for mobile or portable use.

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Transceivers

• Units designed for mobile work usually have easy
  to read displays.
• They should be mounted so that they do not affect
  the drivers ability to safely operate the
  vehicle.

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Yaesu offers many models for mobile operating
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ICOM has its IC-706 and IC-703 (QRP) models
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Kenwoods TS-480 is available in a 200 watt
version
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Alinco DX-70 THHF6m All Modes
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Antenna Systems

• Mobile antenna Systems are comprised of a
  radiator and a matching network.
• Mobile antennas have a low impedance, therefore,
  a matching network is required.

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Antenna 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.

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Antenna SystemsGood, Bad and Ugly

• All systems have some sort of loading.
• Center loading is best.
• Base loading is least effective
• Because of their skinny coils, helically wound
  antennas are a compromise of the other two
  designs.

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SWR

• 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.

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BIG 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.

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Multi Band Antennas

• Motorized
• Automatically tuned
• Manually tuned

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Center Loaded Antennas

• Whether motorized or manually tuned, these
  are by far the most effective type of mobile
  antenna.

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Motorized Antennas

• Commonly 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

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Motorized AntennasAdvantages

• Multi band.
• Can be tuned from inside the vehicle.
• Hi Q Very effective antenna.
• Computerized control units can be added for quick
  band changes.

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Motorized AntennasDisadvantages

• Large and heavy requires strong mounting and
  support brackets.
• Hi Q make tuning on low bands very touchy.

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High Sierra motorized antennas
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Lil Tar heel motorized antenna
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The 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.
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Manually Tuned Center LoadedMulti 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.

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Bug CatchersAdvantages

• Very effective center loaded antennas.
• Large coils results in Hi Q.
• Can be tapped to use on multiple bands

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Bug CatchersDisadvantages

• Large and heavy requires strong mounting and
  support.
• Band changes have to done while parked.

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Large coil and center loading make the Bugcatcher
an excellent performer. This unit is shown with
a capacitance hat.
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Capacitance Hats

• Loss 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.

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CPU 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.

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CPU Controlled Automatically Tuned Multi Band
Antennas

• System can be made low profile.
• Internal memories save settings an allow quick
  band changes.

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CPU 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.

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Interior view of YAESU FC-40 CPU controlled
remote tuner for FT-897 FT-857 radios
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ICOM AH-4 CPU controlled auto-tuner for use with
many ICOM radios
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ALINCO EDX-2for USE exclusively with ALINCO
DX-70T, DX-70TH, DX-77EQ, DX--77T, DX-701 and
DX-707
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SGC makes an entire line of reliable CPU
controlled auto-tuners that will match almost any
radiator with any radio.
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SGCs QMS system is rugged, mounts on any vehicle
and includes the CPU tuner and loaded whip
antenna.
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Mono-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.

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Good results can be had with mono band antennas.
These sticks can be easily mounted and are
lower profile.
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Antenna Mounting

• Which 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.

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Custom Heavy Duty Mount
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Notice the heavy braided ground strap added to
this custom mount ensuring a good bond to frame.
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Custom Heavy Duty Mount
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Dont Be Afraid To Drill A Hole
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Mounting Alternatives
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Mounting Alternatives
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Grounding

• A 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.

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Bonding

• Bonding 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.

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Power

• Power should be taken directly from the vehicles
  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 its job and
  break the circuit.

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Both leads should be fused at the battery to
prevent fire.
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Power

• 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.

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Power

• Flexible 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.

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Grommets and conduit protects wires. Cable ties
keeps things neat.
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Flexible conduit and wire ties keeps all wires
dressed and neat.
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Wires and cables

• Keep 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.

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Mounting The Radio

• The radio should be mounted in such a way that
  it does not interfere with the drivers ability
  to safely operate the vehicle.
• Period.

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Mounting The Radio

• Say it again.
• The radio should be mounted in such a way that
  it does not interfere with the drivers ability
  to safely operate the vehicle.
• Period.

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Mounting The Radio

• The mount should
• Be secure.
• Not obstruct the driver in any way
• Keep the unit within easy reach and view.
• Allow proper air flow and not be in a heat source
  such as heat ducts.

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Mounting The Radio

• Unsecured objects in a vehicle are potential
  hazards in an accident.
• They can be thrown about, hitting the
  occupants with deadly results.

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Mounting The Radio

• A 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.

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Pedestal mounts work well in pick up trucks
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or SUVs
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An aftermarket visor shelf makes a convenient and
safe mount for this ICOM IC-706 control head.
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Gooseneck allows control head to be adjusted.
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Control head of this YAESU FT-100 is mounted
safely and securely and allows the driver to view
it at a glance.
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YAESU FT-857 control head mounted on gooseneck
and radio mounted under passenger seat. A neat
and secure installation.
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Noise

• Grounding 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.

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Noise

• Previously 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.

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Noise

• RFI 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.

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PublicationsYour Mobile Companion

• http//www.arrl.org/catalog/?item5129

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PublicationsARRL Handbook
http//www.arrl.org/catalog/?item9280
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PublicationsARRL Antenna Book
http//www.arrl.org/catalog/?item9043
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Resources

• ARRL on the web
• http//www.arrl.org/tis/info/HF-Mobile.html
• http//www.arrl.org/news/features/1999/11/05/1/

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Contributors

• Thank you to all who supplied pictures of
  their mobile installations
• AB1ER, N1RWY, W2WJO, K3CAV, W3IZ, N5PR,
  K6OWL, W6PW, WØWEB

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Contact

• Norm Fusaro, W3IZ
• ARRL Affiliated Clubs/Mentor
• Program Manager
• 225 Main St. Newington, CT 06111
• 860-594-0230
• w3iz_at_arrl.org