Mobile HF installation guide

How to install HF radio in your vehicle — antennas, power, and noise suppression.

The three problems

Mobile HF requires solving three problems that fixed stations do not have: antenna mounting, ignition noise, and power wiring. Get all three right and mobile HF works remarkably well.

Antenna

The antenna is the most important and most visible part of a mobile HF installation.

Options by commitment level

Antenna Bands Band change Height Cost
Hamstick dipole on mag-mount 1 at a time Swap sticks (stopped) 4 ft $25/band
Hustler resonator on mast 1 at a time Swap resonator (stopped) 5 ft $50/band + mast
Tarheel screwdriver Any (continuous) Dashboard controller (driving) 5-6 ft $500-700
ATAS-120A (Yaesu) Any (auto) Automatic with Yaesu radio 4 ft $200-300
Wolf River Coils Any (manual) Adjust coil tap (stopped) 5 ft $130-200

The practical choice: A Tarheel screwdriver if budget allows (band changes while driving). Hustler resonators if budget is tight (swap resonators when stopped). Hamsticks if you are experimenting (cheapest possible entry).

Mounting

  • NMO mount (drilled hole): Best electrical connection, most permanent. Drill a 3/4" hole in the vehicle body.
  • Trunk lip mount: Good compromise. No drilling. Clamps to the trunk lip or hatchback.
  • Mag-mount: Worst electrical connection but easiest installation. Scratches paint over time.
  • Trailer hitch mount: For heavy screwdriver antennas. Bolt-on, no drilling in the vehicle.

Power wiring

Run dedicated power cables directly from the vehicle battery to the radio location. Do NOT tap into the vehicle's electrical system through the fuse box or cigarette lighter.

  1. Use 10 AWG or heavier wire (red and black)
  2. Run both positive and negative directly to the battery terminals
  3. Fuse the positive lead within 12 inches of the battery (30A fuse for a 100W radio)
  4. Route cables through the firewall using an existing grommet or a drilled hole with a grommet
  5. Keep the cables away from ignition wires, spark plug leads, and the alternator

Ignition noise suppression

Modern vehicles produce RF noise from the engine computer, alternator, fuel injectors, LED lights, and USB chargers. Suppression techniques:

  1. Ferrite chokes on the radio power cables at the radio end
  2. Ferrite chokes on the coax near the radio
  3. Bonding straps between the engine, frame, and body (improves ground continuity)
  4. Alternator noise filter (capacitor across the alternator output, available as a pre-made unit)
  5. LED light replacement: LED headlights and taillights are notorious noise generators. Some are worse than others.

Radio selection

Any HF transceiver works for mobile. Popular choices:

  • Icom IC-7300 — best receiver, largest, requires mounting space
  • Yaesu FT-891 — compact, detachable panel, 100W, designed for mobile
  • Kenwood TS-50S — the original compact HF mobile (discontinued but common used)
  • Icom IC-705 — QRP only (10W) but very compact with built-in battery
  • Xiegu G90 — compact, built-in tuner, affordable

The compact radios (FT-891, G90) fit where the IC-7300 does not. The trade-off is receiver performance for size.