Crimped vs. Soldered Coaxial Cable Terminations

A coaxial cable assembly passes bench testing, then starts dropping signal after a few weeks of field vibration. The cable and connector check out fine. The failure sits in the termination.

Production teams often choose a termination method based on habit or available tooling. That choice affects signal stability, labor time, and field durability. A weak coaxial connector termination can cause intermittent signals, rework, and hard-to-trace returns. Comparing crimped and soldered methods side by side helps engineering and procurement teams match the termination to the application.

How Each Termination Method Works

Both methods connect the center conductor and outer conductor to the connector. Jacket retention depends on the connector design.

Crimped coaxial connectors use a calibrated tool to compress metal around the cable. In a fully crimped design, the center contact is crimped onto the conductor. In this design, a ferrule is crimped over the braided shield, securing it to the connector body. Correct compression forms a gas-tight joint that resists oxidation.

Soldered coaxial connectors bond the conductor to the contact with molten solder. Some designs also solder the outer conductor. Joint quality depends on heat control, flux, and operator technique.

Many connectors combine both methods. A common design solders the center contact and crimps the outer conductor ferrule. Engineers should follow the method the connector manufacturer specifies.

Actual results depend on connector design, cable type, and process control.

Comparing Signal Performance and Repeatability

At RF frequencies, small geometry changes alter impedance. Excess solder, a tilted pin, or a deformed dielectric can create a mismatch. That mismatch increases reflected energy and can increase insertion loss.

Crimping relies on tooling to control geometry. Matched tooling helps control compression. Cable preparation and contact seating also affect consistency.

Soldering can deliver strong signal performance with skilled operators. Manual soldering requires consistent heat application, solder quantity, and inspection. Heat also poses a risk. PTFE dielectrics tolerate soldering heat better than polyethylene, which softens quickly.

Both methods depend on operator training and process control. Build volume and connector design often decide which one fits.

Comparing Strength Under Vibration

This criterion covers the electrical joint itself under cyclic stress.

On stranded conductors and braid, molten solder can wick up between strands. The transition between stiffened and flexible strands can concentrate bending stress. Repeated flexing at this transition can cause fatigue cracks when cable support is inadequate. The result can be an intermittent connection that is hard to reproduce on the bench.

Crimping does not introduce solder wicking at the joint. For soldered designs, control solder wicking according to the applicable workmanship standard and required cable flexibility.

For both methods, vibration performance still depends on connector design, cable support, and qualification testing.

Comparing Mechanical Strength Under Vibration

This criterion covers how well the connector holds onto the cable.

A crimped ferrule grips the outer conductor and, in many designs, the jacket. That grip resists pull out and shares load with the connector body. Teams verify it through crimp dimension checks and pull testing.

Cable retention in soldered designs depends on the connector body, shield attachment, and strain relief. Overheating can also stiffen a braided shield near the connector.

Verify cable retention against the specified pull requirements. Both methods need suitable strain relief for the application, since missing strain relief is one of the routing mistakes that damage coaxial assemblies.

Suitability for Prototype and Volume Builds

Prototypes favor flexibility. Soldering may reduce the need for dedicated crimp tooling. Some connectors still require fixtures, and rework must follow approved instructions. Dedicated crimp dies are hard to justify when the cable or connector may change next revision.

Volume builds often favor crimping. Crimping can shorten termination time, and tooling cost spreads across more units.

One caution applies. If production will use crimped terminations, prototype with them too. Otherwise, qualification data may not reflect production performance.

Method Selection in Regulated Industries

Regulated programs add documentation and validation to the decision.

• Aerospace and defense: Vibration exposure and traceability requirements favor documented, repeatable processes. Customer drawings often specify the termination method as part of how OEMs specify custom coaxial cable assemblies.
• Medical devices: Consistency and change control matter most. Switching termination methods after validation can trigger revalidation.
• Automotive: For coaxial cable assemblies in automotive sensor systems, high production volumes and vibration exposure often favor crimping where the connector design permits it.

In every case, follow the drawing, the connector instructions, and the applicable workmanship standard. Procurement teams should also confirm an assembly partner’s operator training, inspection scope, and first article documentation.

Choosing a suitable coaxial connector termination helps preserve signal integrity and reduce termination-related failures. Contact Star Engineering Inc. to discuss RF coaxial cable assembly requirements, including military and medical cable assemblies tested to customer specifications.

Frequently Asked Questions