Ham Radio in Electric Cars: Step by Step Installation Guide

Installing a Ham Radio in Electric Cars (EV) presents unique challenges that differ from traditional gas-powered car installations. While EVs are quiet, efficient, and increasingly popular, their complex electrical systems can interact unpredictably with radio-frequency equipment.

Nevertheless, with careful planning and a few essential precautions, amateur radio operators can enjoy seamless operation without compromising vehicle performance.

Step-by-Step Guide

Here’s a step-by-step guide for installing ham radios in electric vehicles (EVs), covering antenna placement, wire routing, power feed, and filtering. This guide ensures minimal interference and optimal radio performance without affecting the car’s control systems.

Step 1: Plan Your Installation Layout

Begin by identifying where the radio head unit, power source, and antenna will go. Choose a mounting location inside the cabin that is easily accessible, preferably near the center console or under the dash.

Ensure proper ventilation for the radio.
Leave space for routing coaxial and power cables.

Transition Tip: At this stage, double-check the vehicle’s manual to avoid sensitive modules.

Step 2: Select the Power Source

Electric vehicles typically have a 12V accessory battery used for low-voltage systems. This is your safest and most stable power source.

Run dedicated wires (minimum 12 AWG) directly from the 12V battery terminals.
Add a fuse within 6–12 inches of the positive terminal.
Avoid tapping into existing vehicle circuits, which can overload or interfere with control systems.

Importantly, ground the radio to a clean, bare metal point near the radio chassis, not to a painted surface.

Step 3: Install Ferrite Beads and Noise Filters

Before routing wires, install ferrite chokes on:

Power lines (positive and negative).
Microphone cable.
Coaxial cable near both radio and antenna ends.

Consequently, this helps block RF noise from entering or leaving the radio system.

Additionally, consider a DC noise filter rated for your radio’s current draw. Mount it inline with the positive lead near the radio.

Step 4: Mount the Antenna

Antenna placement is critical. EV bodies often lack continuous metal grounding surfaces, so:

Best Location: Center of the roof using a mag-mount or drilled NMO mount (if the surface allows).
Alternative: Trunk lid, hatchback edge, or a lip mount on the hood.

Tip: Use an antenna with a built-in or supplemental ground plane if the vehicle’s surface lacks one.

However, avoid mounting the antenna near glass panels or solar roofs—they do not offer grounding.

Step 5: Route the Coaxial and Power Cables

Run coax and power cables separately to minimize RF coupling.
Avoid routing near high-voltage orange cables or ECU lines.
Use factory grommets when passing cables through the firewall or trunk bulkhead.

As a result, you reduce the chance of noise pickup or creating RF feedback loops.

Secure cables with zip ties and sleeves to prevent abrasion or disconnection.

Step 6: Final Connections and Grounding

Connect the radio to the fused power leads.
Connect the coaxial cable to the antenna and radio.
Ensure ground continuity between antenna mount and vehicle chassis (test with a multimeter).

If grounding is weak, use braided grounding straps from antenna mount to the chassis or battery negative.

Step 7: Test for Interference

Power on the radio with the car in accessory mode.
Transmit at low power and monitor the car’s systems for anomalies.
Gradually increase transmit power while observing infotainment, backup cameras, sensors, and dashboard lights.

Should any interference appear, adjust the antenna location or add more chokes to affected cables.

Installation Schematic

Here’s a simple block schematic illustrating a clean and filtered install:

 +12V Battery
           |
    [Inline Fuse]
           |
    [DC Noise Filter]
           |
    [Power Cable]
           |                             
    [Ferrite Beads on power cables]           
           |                              
    [Transceiver] Ferrites on mic wire if needed                      
           |
    [Coaxial Cable]
           |
    [Ferrite Beads on coax cable]
           |
    [Antenna]
       (Roof Mount)
       (Ground Strap to Chassis)