RG316 Coaxial Cable: Complete Specs, Applications & Assembly Guide

Published on 10/13/2026

A 300 mm antenna pigtail fits neatly inside your enclosure. Then the lid goes on, the cable folds against a bulkhead connector, and the measured return loss changes. The cable was selected by name, but the assembly was never specified as an electrical and mechanical system. That is where many RG316 problems begin.

RG316 coaxial cable is a compact, flexible 50 Ω cable with a PTFE dielectric and an FEP jacket in common constructions. Its roughly 2.5 mm outside diameter and high-temperature materials make it useful for short equipment interconnects. It is not a substitute for a low-loss feeder or a precision phase-stable test cable.

This guide puts RG316 cable specs into an assembly decision: construction, attenuation, frequency limits, RG316 vs RG174, routing, connector selection and acceptance testing. Numerical examples below are tied to particular published cable constructions or labeled design assumptions. They are not blanket guarantees for every cable sold as RG316.

RG316 construction and core specifications

The common RG316 construction uses a stranded silver-plated copper-clad steel center conductor, solid PTFE insulation, a single silver-plated copper braid and an FEP outer jacket. Copper-clad steel is not the same material as solid copper. Likewise, braid coverage is not the same measurement as shielding effectiveness in dB.

M17/113-RG316 is the 50 Ω flexible coaxial cable specification reference within MIL-DTL-17. A commercial cable can cite that reference while remaining non-QPL. If a defense or aerospace program requires a qualified product, ask for the exact manufacturer, qualified part and procurement evidence. The letters "RG316" on a reel do not settle that requirement.

RG316 attenuation: read the units first

RG316 loss rises with frequency and length. A useful first-order estimate is cable attenuation in dB/m multiplied by finished cable length in m, with connector and mismatch effects considered separately. Do not compare one datasheet in dB/100 ft with another in dB/m without converting them.

The following table converts one published commercial RG316 construction, reference part 83284. Its figures are nominal cable attenuation, not maximum finished-assembly insertion loss. The conversion is 1 dB/100 ft = 1/30.48 dB/m. Values are rounded to 3 decimal places for comparison, not to imply measurement accuracy.

At 2.4 GHz, that example is about 1.549 dB/m. A 0.3 m cable contributes roughly 0.465 dB before allowing for terminations. A 2 m cable contributes roughly 3.097 dB. That is the difference between a sensible internal jumper and a feeder that consumes a large part of the link budget.

A second published RG316 construction specifies 0.870 dB/m at 1 GHz and 1.630 dB/m at 3 GHz at 25 °C. The first reference gives approximately 0.951 dB/m and 1.759 dB/m at those frequencies. Both are real product values. Use the selected cable part, temperature conditions and nominal-versus-maximum definition; do not average the figures into a guaranteed RG316 rating.

Frequency, temperature and power limits

There is no useful universal answer to "What is the maximum frequency of RG316?" without naming the cable and assembled interfaces. One reference construction explicitly specifies operation up to 3 GHz; another supplies nominal attenuation and a VSWR reference through 3 GHz. Those data support decisions in that band. They do not justify a generic 6 GHz, 18 GHz or 40 GHz assembly claim.

For operation above the documented cable band, request a cable and connector combination specified for the intended frequency, together with assembly-level VSWR and insertion-loss limits. A connector capable of a higher frequency cannot extend the qualified performance of the cable behind it. The same rule applies in reverse: a suitable cable cannot fix an unsuitable connector.

Cable voltage, dielectric withstand voltage and RF power are different limits. A hipot test value is not a continuous operating voltage. The RF power limit also depends on frequency, heating, ambient temperature, altitude, VSWR and the connector. For a transmitter, obtain an agreed assembly power rating and derating basis rather than calculating power from a voltage line in a cable datasheet.

RG316 vs RG174: what actually changes

RG316 vs RG174 is often presented as "premium versus cheap." That skips the useful comparison. Both are commonly 50 Ω miniature coax choices. The deciding differences are the specific dielectric, jacket, temperature range, attenuation and approved terminations. Price and availability need a quote for the actual construction and quantity.

These are reference parts 83284 and 8216, not limits shared by every supplier. Notice how close the 100 MHz loss numbers are. At 1 GHz the difference is about 0.164 dB/m, or only 0.049 dB over 300 mm. If the problem is a short low-frequency jumper, thermal and mechanical requirements may matter more than that loss difference.

Do not reuse an RG174 crimp ferrule merely because the cable looks similar. Outer diameter, braid dimensions, dielectric diameter and conductor preparation must match the connector's approved cable group. Consult SigmaRF's cable selection guide for the broader cable-family decision; use this guide when the choice has narrowed to a compact RG316 assembly.

Where RG316 makes sense

Internal antenna jumpersRF equipment interconnectsPanel-to-module linksCompact test fixturesTemperature-constrained routing

RG316 is worth considering when the run is short, the 50 Ω interfaces are known and the routing needs a small flexible cable. Common examples include a module-to-bulkhead antenna lead, an enclosure interconnect and a compact RF fixture. It is flexible, but that word does not mean it is a continuous-flex robotics cable or a metrology-grade test lead.

For stable fixed routing at microwave frequencies, a different flexible cable, semi-rigid or semi-flexible assembly may be the better answer. Review SigmaRF's semi-rigid guides before selecting by diameter alone. For outdoor use, specify sealing, UV exposure, jacket suitability and installation conditions; an FEP jacket does not automatically make connector interfaces weatherproof.

Building a reliable RG316 cable assembly

SigmaRF VNA-sweeps every assembly for VSWR and insertion loss before shipment. Its overall RF assembly capability spans 100 MHz to 40 GHz, with an India (Vadodara) volume facility and a USA (Cleveland area) precision facility. That company-wide range does not make an RG316 assembly a 40 GHz product. The ordered cable, connectors and agreed test band set its performance.

Lead times can be as short as 2 days for suitable builds, subject to parts, quantity and the agreed specification. For repeat orders, retain the approved drawing, cable part, connector part numbers and acceptance limits. SigmaRF's RF cable assembly design guide covers the broader PCB-to-antenna reliability issues; this RG316 guide focuses on getting the small coax interconnect right.

Worked example: a 2.4 GHz pigtail

Suppose a receiver needs a 300 mm RG316 jumper at 2.4 GHz. For this worked example, use the reference 83284 nominal cable attenuation and assume 0.05 dB allowance for each connector. Those connector allowances are design assumptions, not measured SigmaRF values. Set a hypothetical assembly insertion-loss budget of 0.80 dB at 2.4 GHz.

That estimate is a reasonable first pass, not a production limit. Nominal cable attenuation has variation; connectors and bends are not ideal; fixture errors can consume margin. Confirm the finished assembly with a calibrated VNA. If a specification demands 0.80 dB maximum across a band, verify the full band rather than only the 2.4 GHz point.

Now keep the same cable but increase the length to 1 m. The estimate becomes 1.549 + 0.100 = 1.649 dB. It fails the hypothetical 0.80 dB budget before mismatch is considered. Better connector marketing will not recover that length penalty; shorten the route or select a lower-loss cable.

For delay, a 70% velocity factor gives roughly 4.77 ns/m, so 300 mm contributes about 1.43 ns. That is an estimate from the nominal velocity factor. If phase matching matters, specify electrical length and measure it; two cables cut to the same mechanical length need not have identical phase.

Common RG316 assembly mistakes

The failure that wastes the most time is a vague acceptance condition. "Good VSWR" is not a limit, and a connector rated above the cable band is not a test result. Specify what passes, at which frequencies and at which reference planes. See SigmaRF's VSWR and impedance matching guide for the relationship between VSWR, return loss and reflected power.

RG316 questions engineers and buyers ask

Bottom Line

RG316 is a useful small 50 Ω interconnect when its materials, documented band and loss fit the job. Its strongest case is a short, carefully routed jumper. It is a poor choice when length, continuous flexing, phase stability or an unsupported frequency claim is doing the hard work in the design.

Start with the exact cable construction, then select compatible connectors and a sensible route. Define the finished length and acceptance limits before the first assembly is built. That turns "RG316 coaxial cable" from a shopping term into a repeatable engineering specification.

For procurement, send SigmaRF the drawing and operating requirements rather than asking for a cable name alone. The useful result is a verified assembly that fits, survives its environment and meets the agreed RF limits, not the highest number on a connector datasheet.