HomeTips & GuidesCar Antenna Extension Cable: Types, Benefits, Factors To Consider, and More!

Car Antenna Extension Cable: Types, Benefits, Factors To Consider, and More!

Most car features that require external antennas like GPS and AM/FM radio use coaxial cables to get the signals from the antenna. A car antenna extension cable is an equivalent coaxial cable that allows you to connect the head unit and antenna over a longer distance.

You might have to use this extension cable if your head unit upgrade has a short antenna wire or if you mount the antenna further up the vehicle to improve reception. 

Here’s all you need to know about this cable, including its installation process and factors to consider.

Types of Car Antenna Extension Cables

Although most, if not all, of these car antenna extension cables are coax cables, they can have different functions. Their types match the function and include the following.

  • FM antenna extension cables
  • Satellite radio cables (such as for XM radio)
  • AM antenna extension cables
  • Wi-Fi reception cables
  • GPS antenna cable

Each coaxial RF cable has unique performance tweaks, including different connectors, to match the specific application.

A black plastic radio AM-FM antenna

A black plastic radio AM-FM antenna

Benefits of Using Car Antenna Extension Cables

  • Extended Reception Range: An extension cable lets you position the antenna in an area with a better line of sight to the transmitter, extending your signal reception range when driving.
  • Reduced Interference: Relocating the antenna from areas with other electrical devices or metal structures reduces signal interference, resulting in clearer reception.
  • Flexible Installation Option: This cable gives you the flexibility to mount the antenna at a convenient place. It could be for aesthetics or to avoid obstacles (interference).
  • Tailored Cable Length: These cables are available in different lengths, meaning you can tailor the installation to match any distance between the radio and the antenna.
  • Universal Compatibility: These extension cables feature different connectors to match the ports in various antenna systems and aftermarket radios.
  • Easy to Install: Antenna extension cables are easy to install because they have ready-to-insert connectors. You don’t need technical expertise to fix them.
  • Cost-Effective Solution: Instead of replacing the complete antenna setup, this extension solution offers a cheaper alternative while delivering similar reception quality.

Factors To Consider When Selecting Car Antenna Extension Cables

These factors are critical when selecting a car antenna extension cable for the best signal reception and audio quality (for radio).

Cable Length

The longer the car antenna extension cable’s length, the higher the signal losses along the line. Therefore, you should not install a cable that is longer than necessary.

A car radio AM/FM antenna with a short cable

A car radio AM/FM antenna with a short cable

If the cable’s length exceeds 50 feet, install an inline amplifier to maintain signal strength and integrity. 

Cable Design

Low-loss cables built using high-quality materials maintain signal integrity over long distances. Losses usually occur due to dielectric signal absorption, imperfect shielding (signal radiation), and resistive losses along the conductors.

Therefore, the type and quality of the construction materials matter. Look for features like the impedance rating, which affects transmission losses.

For instance, 30-ohm or 50-ohm impedance coaxial cables are better for Wi-Fi antennas, while 75-ohm cables can transmit video and audio with minimal losses.

The internal structure of a coaxial cable

The internal structure of a coaxial cable


Electromagnetic or radio frequency interference can significantly hamper signal transmission, making the signal impure when exiting the line.

Therefore, shielding is critical, especially if the wire passes through environments with electronic interference from other components.

Frequency Range

The extension cable should match the application by bearing a matching frequency or be within the acceptable frequency range.

FM, AM, and TV reception can work perfectly with low-frequency extension cables, but wireless internet reception requires higher-frequency cables.

Connector Type

The extension cable’s connector also plays a critical role in the signal transmission. Typical ones include SMA, DIN, FME, and Fakra, and this component should be compatible with the antenna and the head unit.

A car radio antenna adapter with Fakra connectors

A car radio antenna adapter with Fakra connectors


If the extension cable’s route passes through an area exposed to the elements, it should have a thick skin that can withstand these exterior conditions.

Vibrations can also damage the cable, and the insulation should be sturdy enough to withstand this abuse.

How To Install a Car Antenna Extension Cable

After identifying and buying the most suitable antenna extension cable, install it using these steps. You’ll need these tools.

  • Screwdriver
  • Pair of pliers
  • Wrench
  • Panel removal tool
  • Zip ties and cable clips

Step 1: Disconnect the Car Battery

Loosen and remove the negative battery terminal (black color wire) from the lug for safety.

Step 2: Find the Existing Antenna Cable

Locate the antenna cable you want to extend in your vehicle. You might have to remove the plastic dashboard panels to access this cable behind the head unit.

Step 3: Connect the Extension Cable to the Radio

Disconnect the existing antenna cable from the head unit, then attach one end of the extension cable to the head unit. Fasten the joint. For threaded connectors like SMA, apply the required torque.

The backside of a single din head unit (note the antenna port)

The backside of a single din head unit (note the antenna port)

Step 4: Route the New Cable

Channel the cable from the head unit to where you want to mount the antenna. You might have to remove more plastic panels to route this cable. Once in place, tie it to the chassis using the cable clips and zip ties.

Step 5: Mount the Antenna

Install the new antenna or move the existing one to the new location where you’ve routed the extension cable to reach.

A car antenna mounted on the roof to get better reception

Step 6: Connect the Cable to the Antenna

Attach the other end of the extension cable to the antenna connector and fasten the joint. You can weatherproof this joint if exposed to the elements. Use electrical tape or heat shrink tubing to seal the connection.

Step 7: Reconnect the Battery

Reconnect the negative battery terminal and turn on the vehicle to test the system’s reception. Make any necessary adjustments before fitting the plastic interior panels back in place.

An AM/FM roof antenna

Wrap Up

When dealing with car antenna extension cables, the most critical factor to check is the signal losses or attenuation.

Most manufacturers label the maximum length you can extend the connection because it is possible to link multiple cables or the extension to the existing one.

You are safer using the extension cable alone, which is the installation we’ve done above.

Contact us if you find picking an antenna extension cable challenging, and we’ll sort you out. 

Hey, I am Lillian Yang, Sales manager of Cloom Tech.

I am a responsible, intelligent and experienced business professional with an extensive background in the electronics industry.

Reach me at [email protected] to get a quote for your projects.

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