KH-FAKRADK-FAKRADK-RG174-350MM FAKRA Purple D-Code Female-to-Female RF Cable Explained

In automotive electronics, in-vehicle communications, antenna feeder systems, positioning and navigation, cameras, T-Box systems, in-vehicle infotainment connectivity, and RF testing, RF cable assemblies may appear to be only a small component of a wiring harness system. However, they directly affect signal transmission stability, interference resistance, and installation efficiency.

The KH-FAKRADK-FAKRADK-RG174-350MM from Kinghelm is an RF cable assembly featuring FAKRA purple D-code female connectors on both ends, using RG174 coaxial cable with a total cable length of 350 mm. It is suitable for compact installation spaces and applications requiring short-distance RF interconnection, extension, or signal routing. It is a common connection solution for automotive RF and wireless communication wiring systems.

Kinghelm KH-FAKRADK-FAKRADK-RG174-350MM Product Image

1. Product Overview and Basic Positioning

This product belongs to the RF cable assembly category. The brand is Kinghelm, and the product model is KH-FAKRADK-FAKRADK-RG174-350MM.

According to the product specifications, it is a FAKRA purple D-code female-to-female RF cable assembly using RG174 coaxial cable, with a cable length of 350 mm. Both ends are equipped with FAKRA female connectors with female center contacts. The connector housings are purple or purplish-red and use D-code mechanical keying.

The product is packaged in bags, with a gross weight of approximately 12.95 g. For customers requiring volume purchasing, maintenance replacement, or sample testing, clearly defined specifications such as these make product selection and identification more convenient.

2. Structure and Appearance Design

Both ends of this cable assembly use FAKRA female connectors with female center contacts. The connector housings are purple or purplish-red and feature D-code keying.

FAKRA connectors are widely used in automotive RF applications. One of their key advantages is their color coding and mechanical keying system. Different codes correspond to different colors and mechanical key positions, helping to prevent incorrect connections.

D-code connectors are commonly identified by a purple or purplish-red housing. Therefore, users can quickly identify the connector coding type through the color of the housing.

The female connector design allows the cable assembly to mate with corresponding FAKRA male connectors, making it suitable for connecting, extending, or routing RF signals between two male-ended interfaces.

The cable itself uses RG174 coaxial cable with a black outer jacket and an outer diameter of approximately 2.8 mm. RG174 coaxial cable is flexible, compact in diameter, and easy to bend and route. It is particularly suitable for installation in confined spaces inside vehicles, test fixtures, or internal equipment modules.

Compared with thicker coaxial cables, RG174 offers greater flexibility and weight advantages.

Black heat-shrink tubing is also used at the cable-to-connector transition areas. The tubing specification is OD: 3.5 × 15 mm. The heat-shrink tubing provides insulation, dust protection, resistance to light pulling forces, and additional bend protection, improving the mechanical reliability of the connection area.

3. Key Specification Analysis

According to the available specifications, the cable length is 350 mm, and the rated voltage is 300 V.

A 350 mm cable is considered a relatively short RF connection length and is suitable for interconnecting devices located close to each other. Typical examples include connections between vehicle head units and antenna modules, RF modules and interface panels, or test equipment and fixtures.

A shorter cable length can help reduce signal attenuation while making cable management easier in compact installation spaces.

The 300 V rated voltage indicates that the insulation capability of the cable assembly can meet the general requirements of low-voltage electronic equipment and automotive RF systems.

RG174 coaxial cable typically has a characteristic impedance of 50 ohms, which is a common impedance standard in RF systems.

In actual applications, electrical performance parameters such as insertion loss, voltage standing wave ratio (VSWR), and operating frequency range may be affected by connector manufacturing quality, cable material, assembly accuracy, and the operating environment. Therefore, for high-frequency or high-reliability applications, users are recommended to refer to the actual product datasheet or factory test data.

The gross weight of the product is approximately 12.95 g, and it is supplied in bag packaging, making it lightweight and convenient for storage, distribution, and individual use.

4. FAKRA D-Code Keying and the Importance of Mis-Mating Prevention

The coding system of FAKRA connectors is one of the major reasons they are widely used in automotive applications.

Through different colors and mechanical keying structures, FAKRA connectors can be used to distinguish different RF signal systems, such as:

• Radio antennas
• GPS and navigation systems
• Cellular communications
• Automotive cameras
• Wi-Fi
• Bluetooth
• Other automotive RF communication systems

The purple or purplish-red D-code housing not only provides easy visual identification but also helps reduce the risk of incorrect connections during installation.

For maintenance personnel and installers, once the equipment-side connector is confirmed to use D-code keying, a corresponding FAKRA cable assembly can be selected to improve installation efficiency and reduce connection errors.

FAKRA connectors typically use a locking mechanism. Users can usually feel a clear locking engagement after the connector is properly inserted.

When disconnecting the connector, the release latch should be pressed before removal. Excessive pulling on the cable should be avoided.

Although the female connector and female center-contact design is suitable for repeated mating cycles, users should still keep the connector interfaces clean and avoid contamination by dust, oil, moisture, or metal particles.

5. Advantages and Application Limits of RG174 Coaxial Cable

RG174 is a commonly used flexible coaxial cable featuring a small diameter, low weight, and a relatively small bending radius, making it suitable for high-density cable routing.

Its black outer jacket provides a certain degree of resistance to wear and contamination. With an outer diameter of approximately 2.8 mm, it can also be routed through narrow openings, cable channels, and compact installation spaces.

The relatively short 350 mm cable length makes this product practical for applications such as automotive antennas, RF modules, test fixtures, and laboratory module interconnections.

However, because RG174 has a relatively small cable diameter, its high-frequency attenuation is generally higher than that of thicker and lower-loss coaxial cables.

Therefore, when the application involves very high operating frequencies, long transmission distances, or strict signal-loss requirements, users should evaluate whether a lower-loss coaxial cable is more suitable.

For short-distance connections such as 350 mm, RG174 can still provide practical and stable performance in many automotive RF, navigation, radio, camera, and general wireless communication applications.

6. Heat-Shrink Tubing and Connection Reliability

The cable assembly uses black heat-shrink tubing at the connector tail, with a specification of OD: 3.5 × 15 mm.

After heating, the tubing tightly covers the cable-to-connector transition area. This helps reduce cable damage caused by repeated bending or pulling and can also provide a certain degree of dust protection, moisture resistance, and electrical insulation.

For automotive environments involving vibration and movement, this protective design can help improve the service life and mechanical reliability of the cable assembly.

During installation, excessive heating of the heat-shrink tubing should be avoided to prevent damage to the cable jacket or internal connector structure.

7. Typical Application Scenarios

The Kinghelm KH-FAKRADK-FAKRADK-RG174-350MM can be used in a variety of RF interconnection applications, including:

• Automotive radio antenna extensions
• GPS/BeiDou antenna connections
• T-Box communication modules
• Vehicle infotainment head units
• Automotive camera signal connections
• V2X communication modules
• Wireless communication equipment
• RF test fixtures
• Laboratory module interconnections

Because both ends use FAKRA female connectors, the cable assembly is typically used to connect two FAKRA male interfaces or to provide short-distance signal extension and interconnection.

If the equipment interface itself uses a female connector, a suitable male adapter or an alternative connector configuration may be required.

8. Selection and Installation Recommendations

When selecting this product, users should confirm the following key points:

1. Whether the interface requires a FAKRA female connector with a female center contact.
2. Whether the required mechanical coding is D-code with a purple or purplish-red housing.
3. Whether RG174 coaxial cable is suitable for the application.
4. Whether a cable length of 350 mm meets the installation requirements.
5. Whether the 300 V rated voltage meets the system requirements.
6. Whether the installation space is suitable for the approximately 2.8 mm cable diameter and the 3.5 × 15 mm heat-shrink protection area.

During installation, sharp bends should be avoided and an appropriate bending radius should be maintained.

When mating or disconnecting the connectors, users should align the mechanical keying correctly and operate the locking mechanism properly. Forced rotation, excessive side loading, or pulling directly on the cable should be avoided.

Kinghelm KH-FAKRADK-FAKRADK-RG174-350MM Datasheet

9. Brand and Packaging Information

Kinghelm is well known in the fields of RF connectors, antennas, and cable assemblies.

The product model is KH-FAKRADK-FAKRADK-RG174-350MM. It is supplied in bag packaging and has a gross weight of approximately 12.95 g.

Clear product model identification and numbering facilitate purchasing, inventory management, and maintenance replacement.

For customers requiring stable supply and consistent product specifications, selecting standardized product models can help reduce selection errors and installation risks.

Conclusion

Overall, the Kinghelm KH-FAKRADK-FAKRADK-RG174-350MM is a compact and flexible FAKRA purple D-code female-to-female RF cable assembly with clearly defined specifications.

It uses RG174 coaxial cable with a black outer jacket, an outer diameter of approximately 2.8 mm, and a cable length of 350 mm. The rated voltage is 300 V, and both ends feature FAKRA female connectors with female center contacts. The connector transition areas are protected by black heat-shrink tubing with a specification of OD: 3.5 × 15 mm. The product is supplied in bag packaging and has a gross weight of approximately 12.95 g.

It is suitable for short-distance RF interconnection applications involving automotive electronics, antennas, navigation systems, cameras, communication modules, and RF testing and measurement equipment.

With correct product selection, proper installation, and appropriate maintenance, this cable assembly can provide stable and reliable performance for RF signal transmission.

About Kinghelm

Kinghelm (www.kinghelm.net), a national high-tech enterprise with more than a decade of experience in the RF and interconnection industry, specializes in the design, manufacturing, sales, and technical services of wireless signal transmission and reception products, electronic signal connectors, and interconnection systems.

Its comprehensive product portfolio covers Type-C, SMA, IPEX, MCX, HDMI connectors, automotive wiring harnesses, adapter cables, RF connectors, electronic components, millimeter-wave sensors, and a complete range of tactile switches, detection switches, slide switches, push-button switches, micro switches, and multifunction switches.

With more than 8,000 SKUs, Kinghelm's products are developed and manufactured in accordance with standards and certification requirements such as ISO 9001, ISO 14001, RoHS, and REACH.

Supported by the research and development expertise of technical teams associated with Tsinghua University and the University of Electronic Science and Technology of China, Kinghelm products are widely used in communications, automotive electronics, industrial control, and IoT applications.

Combining high reliability, broad compatibility, and strong cost performance, Kinghelm provides both standardized mass-production products and end-to-end customized solutions, making it a trusted provider of RF and interconnection solutions for customers across multiple industries.

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